normas texaco gems j-1d22 piping design

DEC 97 PIPING - DESIGN GEMS J-1D22

PAGE 1 OF 52©TEXACO GENERAL ENGINEERING DEPARTMENT

TABLE OF CONTENTSPAGE

1. SCOPE .............................................................. 3

2. REFERENCES ......................................................... 3

2.1 Purchaser Specifications ..................................... 32.2 Purchaser Drawings ........................................... 42.3 Industry Codes and Standards ................................. 5

3. DESIGN ............................................................. 6

3.1 Design Pressure .............................................. 63.2 Design Temperature ........................................... 73.3 Design Minimum Temperature ................................... 93.4 Occasional Variations (Short Term Conditions) Rating ......... 93.5 Steam-out Philosophy ......................................... 93.6 Line Designation Tables ...................................... 9

4. LINE SIZING ........................................................ 10

4.1 General ...................................................... 104.2 Sizing Criteria .............................................. 104.3 Specific Services ............................................ 114.4 Minimum Line Size ............................................ 12

5. EQUIPMENT LOCATION AND ACCESSIBILITY ............................... 13

5.1 Definitions .................................................. 135.2 Accessibility of Valves ...................................... 145.3 Instrument Location and Accessibility ........................ 155.4 Platforms .................................................... 16

6. PIPING DESIGN AND ARRANGEMENT - GENERAL ............................ 16

6.1 General ...................................................... 166.2 Elevations ................................................... 176.3 Change in Direction .......................................... 176.4 Injection Points ............................................. 176.5 Pockets and Dead Ends ........................................ 186.6 Unit Blocks .................................................. 186.7 Unit Pumpout/Off Test System ................................. 186.8 Precommissioning ............................................. 196.9 Break Joints ................................................. 196.10 Winterproofing and Line Heating .............................. 196.11 Insulation Support Rings ..................................... 196.12 Insulating Pipe Flanges (Electrical) ......................... 196.13 Vents in Piping .............................................. 196.14 Drains in Piping ............................................. 206.15 Drain Piping (Aboveground) ................................... 206.16 Blinds ....................................................... 226.17 Utility Station Piping ....................................... 246.18 Instrument Piping Connections ................................ 25



6.19 Safety Showers and Eyewash Fountains ......................... 266.20 Sample Connections ........................................... 266.21 Clearances ................................................... 266.22 Block Valves ................................................. 276.23 Check Valves ................................................. 286.24 Pipe Plugs ................................................... 29

7. PIPING DESIGN AND ARRANGEMENT - SPECIFIC SERVICES .................. 29

7.1 Vessel Piping ................................................ 297.2 Heat Exchanger Piping ........................................ 307.3 Pump Piping .................................................. 317.4 Compressor Piping ............................................ 337.5 Fired Heater Piping .......................................... 357.6 Relief System Piping ......................................... 367.7 Steam and Condensate Piping .................................. 377.8 Air Piping ................................................... 397.9 Water Piping ................................................. 397.10 Oxygen Service Piping ........................................ 407.11 Underground Piping ........................................... 407.12 Offsite Interconnecting Piping ............................... 427.13 Tankage Piping ............................................... 437.14 Truck and Tank Car Loading Facilities ........................ 447.15 Fluid Catalytic Cracking Units (FCCU) ........................ 447.16 Acid and Caustic Lines ....................................... 44

8. PIPING EXPANSION, FLEXIBILITY, AND SUPPORT ......................... 45

8.1 Thermal Expansion of Piping .................................. 458.2 Pipe Supports and Anchors .................................... 468.3 Piping Flexibility Analysis .................................. 49



1. SCOPE

1. This specification, together with referenced specifications, definesrequirements for design of piping systems.

2. This specification shall apply to piping systems covered by ASMEB31.3.

3. Piping that is within the scope of Section I, ASME Boiler andPressure Vessel Code, or ASME B31.1 shall be governed by those codesand applicable parts of this specification that do not conflict withthose codes.

4. Unless specified otherwise, piping specified in accordance with thefollowing specifications shall not be bound to this specification:

a. ASME B31.4.

b. ASME B31.8.

2. REFERENCES

2.1 Purchaser Specifications

This specification contains references to the following Purchaserspecifications:

1. GEMS F-1M, “Pressure Vessels - Carbon Steel and Alloy - MaterialPurchase”.

2. GEMS G-1D, “Winterproofing and Weather Protection”.

3. GEMS G-2D, “Refinery Process Unit Layout”.

4. GEMS G-3D, “Climatic Design Data”.

5. GEMS G-4D, “Noise Control”.

6. GEMS G-5D, “Design of Flare Systems”.

7. GEMS H-1M, “Design and Fabrication of Fired Heaters (API 560)”.

8. GEMS I-3M, “Cold Insulation”.

9. GEMS J-2D, “Selection and Limitation of Piping Materials”.

10. GEMS J-3D, “Sewers, Drains, and Paving Arrangement”.

11. GEMS J-6D, “Steam Traps”.

12. GEMS J-8D, “Steam Tracing Systems - Design”.

13. GEMS J-3M, “Piping Fabrication and Erection”.

14. GEMS J-6M, “Exterior Coal-Tar Coating for Buried Steel Pipe”.

15. GEMS J-1P, “Field Pressure Testing of Piping, Sewers, Fired HeaterTube Assemblies, and Exchangers”.

16. GEMS J-2P, “Internal Pipe Cleaning”.

17. GEMS K-2D, “Sizing, Selection, and Installation of Pressure ReliefDevices”.

18. GEMS K-3D, “Overpressure Protection”.

19. GEMS K-19D, “Instrument Utilities - Electrical and Air”.

20. GEMS L-2D, “Cathodic Protection Systems”.

21. GEMS L-3D, “Electric Heat Trace Systems”.



22. GEMS M-3D, “Design of Water Systems for Fire Protection”.

23. GEMS S-1M, “Fabrication and Erection of Structural Steel”.

24. GEMS U-1M, “Induced Draft Cooling Towers”.

25. DP 70, “Emergency Isolation and Depressuring Valves”.

26. “Liquefied Petroleum Gas (LPG) Storage and Handling Guidelines”.

2.2 Purchaser Drawings

This specification contains references to the following Purchaserdrawings:

1. 1S-1781, “Flow Diagram, Typical Arrangement, Refinery Flare GasSystems (2 Sheets)”.

2. 1S-1784, “Utility Instrument Requirements at Unit Limits”.

3. 1S-1856, “Heater Natural Draft Fuel Gas Combustion Control”.

4. 1S-1857, “Heater Forced Draft Fuel Gas Combustion Control”.

5. 1S-1858, “Heater Forced Draft Fuel Gas Combustion Control Lead/Lag”.

6. 1S-1859, “Heater Forced Draft Combustion FO/FG Combustion Control”.

7. 1S-1860, “Heater Liquid Inlet Control”.

8. 1S-1861, “Heater Gas Inlet Control”.

9. 1S-1862, “Heater Mixed Inlet”.

10. 1S-1863, “Heater Shutdowns”.

11. 3S-2468, “Typical Fittings for Spheres”.

12. 3S-2470, “Typical Fittings for LPG Horizontal Storage Vessels”.

13. 3S-2471, “Details - Fittings for LPG Vessels(Sheet 1)”.

14. 3S-2472, “Details - Fittings for LPG Vessels(Sheet 2)”.

15. 6S-6892, “General Platform Requirements - Vertical and HorizontalVessels”.

16. 6S-7257, “Clearances for Top Tray Removal Platform and Typical PSVArrangement for Vessels Greater Than 3 Feet 0 Inch I.D.”.

17. 9S-7165, “Typical Steam Connections and Piping to Vessels andEquipment”.

18. 9S-7412, “Standard Sample Condenser Assembly and Details”.

19. 9S-7413, “Typical Details for Utility Steam, Water, and Air HoseStations”.

20. 9S-7581, “Vent and Drain Nozzles for Shell and Tube Exchangers”.

21. 9S-7651, “Standard Bossed and Tapped Connections for Valves in FCCUCatalyst Service”.

22. 9S-7686, “Clearance at Exchangers Supported from Grade”.

23. 9S-7690, “Detail of Steam Tracer Piping”.

24. 9S-8124, “Control Valve Piping Arrangement, Block Valve Size, andBypass Requirements”.

25. 9S-8125, “Piping Details for Cage Type Displacement LevelInstruments”.

26. 9S-8161, “Typical Valve Boxes for Underground Valves”.



27. 9S-8168, “Field Test Blinds for ANSI Raised Face and Ring JointFlanges”.

28. 9S-8200, “Cooling Water Piping Manifold for Pumps and Turbines”.

29. 9S-8261, “Typical Steam Piping - Pumps and Turbines”.

30. 9S-8262, “Typical Piping - Liquid End of Pumps”.

31. 9S-9166, “Requirements and Piping for Direct Connected GaugeGlasses”.

32. 9S-9172, “Typical Reboiler Condensate Piping”.

33. 9S-9173, “Typical Sample Piping Hookup”.

34. 9S-9175, “Typical Backwash Piping”.

35. 9S-9258, “Typical Instrument Air Supply Piping Showing Main Header,Sub-Header, and Individual Take-offs”.

36. 9S-9344, “Typical Piping for Fired Hydrocarbon Heaters - Sheet 1”.

37. 9S-9345, “Typical Piping for Fired Hydrocarbon Heaters - Sheet 2”.

38. 9S-9346, “Piping for Exchangers that may be Removed from Serviceduring Operation”.

39. 9S-9347, “Typical Manifold and Quench Drum for Heater Decoking”.

40. 9S-9357, “Typical Arrangements at Process Unit Limits”.

41. 9S-9367, “Continuous Air Injection into HC Lines - Reverse FlowProtection”.

42. 13S-378, “Details - Thermal Insulation, Supports, and Metal Jacketfor Piping”.

43. 13S-381, “Details - Cold Insulation, Supports, and Metal Jacket forPiping”.

2.3 Industry Codes and Standards

This specification contains references to the following industry codesand standards:

2. 3 .1 American Petroleum Institute (API)

1. Std 600, “Steel Gate Valves - Flanged and Butt-WeldingEnds”.

2. Std 602, “Compact Steel Gate Valves”.

3. Std 610, “Centrifugal Pumps for General Refinery Service”.

2. 3 .2 American Society of Mechanical Engineers (ASME)

1. B31.1, “Power Piping”.

2. B31.3, “Chemical Plant and Petroleum Refinery Piping”.

3. B31.4, “Liquid Transportation Systems for Hydrocarbons,Liquid Petroleum Gas, Anhydrous Ammonia, and Alcohols”.

4. B31.8, “Gas Transmission and Distribution Piping Systems”

5. “Boiler and Pressure Vessel Code”.

a. Section I, “Power Boilers”.

b. Section VIII, “Pressure Vessels”, Division 2, “AlternateRules”.



2. 3 .3 Compressed Gas Association (CGA)

G-4.4, “Industrial Practices for Gaseous Oxygen Transmissionand Distribution Piping Systems”.

2. 3 .4 National Electrical Manufacturers Association (NEMA)

“Publication SM 23, Part 8 (Steam Piping Systems)”.

2. 3 .5 Other

“Cameron Hydraulic Data Book”.

3. DESIGN

3.1 Design Pressure

Design pressure of piping shall be determined on the following basis:

1. Design pressure generally shall not be less than maximum sustainedoperating pressure plus the following allowance:

Maximum Sustained Operating Pressure AllowanceLess than 14.7 psia (vacuum) 10%0-100 psig 10 psi100-500 psig 10%Greater than 500 psig 50 psi

Allowances less than the above shall require individualconsideration and written Purchaser approval. Allowance shall not berequired for conditions described in paragraphs 2. through 5. below.

2. Discharge piping of centrifugal pumps and centrifugal compressorsshall have a design pressure that is not less than maximum dischargepressure of all conditions. Design pressure shall includeconsideration individually of the following type of single jeopardyconditions, if they are appropriate, and combinations of theseconditions that are expected to occur simultaneously. Normally,multiples of these, and sometimes all, conditions may occursimultaneously and therefore should be considered in combination.

a. Maximum pressure at suction flange. If appropriate, the followingshall be considered:

(1) Suction pressure safety valve at its set pressure.

(2) Maximum liquid level in pump suction system.

(3) Maximum shutoff supply pressure from suction booster pump.

b. Maximum head at low or no flow. Purchased pump curve shall beused for pumps, or it shall be assumed that maximum pump head is130% of pump design head.

c. Maximum liquid density, such as lowest °API and/or coldestpumpage anticipated.

d. Maximum molecular weight gas anticipated.

e. Maximum driver speed. Speeds above constant speed or speedcontrol range, such as overspeed trip setting, shall beconsidered, if appropriate, but associated discharge pressureshall only be within occasional (short term) pressure rating ofpiping in accordance with Section 3.4.

3. Design pressure of piping protected by a pressure relief valve (PRV)on an interconnected equipment system shall not be less than pipingpressure expected when pressure relief valve reaches set pressure.



As outlined in GEMS K-3D, protected piping upstream of the PRVlocation shall have a design pressure sufficiently higher than PRVset pressure to account for maximum system pressure drop betweenprotected piping and PRV location. Protected piping downstream ofPRV location shall have a design pressure at least equal to PRV setpressure to account for minimum pressure drop of zero for no flow.

4. Design pressure of piping shall not be less than maximum pressurethat may occur for any of the following type conditions:

a. Starting up operations, including any start-up procedure,operation, or routing.

b. Shutting down operations, including shutdown procedures,operations, and pumpout.

c. Switching operations, including any cyclic regeneration, sparepump switching, and coke drum switching.

d. Regeneration procedures.

e. Equipment bypassing.

f. Turndown operations.

g. Pump shutoff.

h. Control valves in fully open or fully closed position.

i. Block valves in fully open or fully closed position, except forlocked valves.

j. Blocked exits.

k. Equipment trip or shutdown.

l. Misoperation.

m. Maintenance, repair, or neutralization procedures.

n. On-stream testing procedures.

o. Steam-out (see Section 3.5) or purging operations.

p. Other causes of increased pressure.

5. Design pressure of flare system piping and other PRV dischargepiping shall be:

a. At least 50 psig.

b. Not less than maximum back pressure during any relief.

6. Design pressure shall be considered coincident with piping designtemperature determined per Section 3.2, except if a more economicaldesign is used by giving piping two or more sets of designpressure/temperature combinations. For example, hydrotreater reactorpiping may have separate design combinations for hydrotreating (highpressure) and regeneration (high temperature). Design shall includefeatures to prevent inadvertent combinations of high pressure andtemperature.

3.2 Design Temperature

Design temperature of piping shall be determined on the following basis:

1. Design temperature shall not be less than maximum sustained fluidoperating temperature plus an allowance that is normally 50°F. Anallowance less than 50°F shall require individual consideration andwritten Purchaser approval. Allowance shall not be required forconditions described in paragraphs 2. through 4. below.



2. Design temperature of piping shall not be less than maximum fluidtemperature that may occur for any of the following type conditions:

a. Starting up operations, including any start-up procedure,operation, or routing.

b. Shutting down operations, including shutdown procedures,operations, and pumpout.

c. Switching operations, including any cyclic regeneration or cokedrum switching.

d. Regeneration procedures.

e. Equipment bypassing.

f. Turndown operations.

g. Control valves in fully open or fully closed position.

h. Block valves in fully open or fully closed position, except forlocked valves.

i. Equipment trip or shutdown.

j. Misoperation.

k. Maintenance, repair, or neutralization procedures.

l. Steam-out (see Section 3.5) or purging operations.

m. Other causes of increased temperature.

3. Flare system piping and other PSV discharge piping shall have adesign temperature that is determined from temperature of fluidbeing relieved, taking into account temperature change across PSVand thermal effects in discharge piping.

4. Design temperature of heat traced and insulated piping shall not beless than maximum metal temperature expected for no flow conditions.For steam tracing, steam saturation temperature at steam supplypressure shall be used.

5. Design temperature of internally insulated piping shall be based onheat transfer calculations or tests.

6. Thermal expansion stress calculations for piping shall be based onthe higher of:

a. Piping design temperature.

b. Occasional (short term) temperature rating of piping, ifapplicable, per Section 3.4.

Thermal expansion stress calculations shall also consider pipingdesign minimum temperature per Section 3.3.

7. Piping metallurgy for corrosion resistance shall be selected inaccordance with maximum sustained operating temperature withoutadding 50°F allowance of paragraph 1. If appropriate for corrosionresistant/time duration, higher temperature basis of paragraph 2.shall be used.

8. Except if multiple design pressure/temperature combinations are usedas described in Section 3.1, paragraph 6., piping design temperatureshall be considered to be coincident with piping design pressure.



3.3 Design Minimum Temperature

Design minimum temperature of piping shall be determined on the basis ofthe following:

1. Design minimum temperature of piping shall not exceed winter drybulb design temperature for location per GEMS G-3D, except for anyof the following:

a. Piping that is located inside a heated building.

b. Piping that is heat traced and insulated.

c. Piping that is underground.

2. Design minimum temperature of piping subject to autorefrigerationcaused by low pressure vaporization of a volatile liquid, such aspropane, shall not be greater than atmospheric pressure boilingtemperature of liquid. If liquid is a mixture, bubble pointtemperature of mixture at atmospheric pressure shall be used. (NoteASME B31.3 provision for exempting impact testing at lowertemperatures if pressure and longitudinal stresses are low.)

3.4 Occasional Variations (Short Term Conditions) Rating

1. Occasional variations refer to occasional, short duration variationsof pressure, temperature, or both above piping design pressure andtemperature.

2. Occasional variations (short term pressure and/or temperature)ratings may be used for conditions other than those outlined inSections 3.1 and 3.2, but they shall conform to requirements of ASMEB31.3.

3.5 Steam-out Philosophy

1. In steaming out equipment and piping systems, during a shutdown orin preparation for start-up, steam (normally medium pressure) isbled into system toward a large piece of equipment where sufficientvents and drains are open to prevent appreciable pressure buildup.

2. Steam-out design shall be based on premise that piping and equipmentare at no time subject to steam pressures above 50 psig or to metaltemperatures above 300°F.

3.6 Line Designation Tables

A tabulation of the following information shall be provided for eachline:

1. Line number.

2. Nominal pipe size.

3. Service symbol per GEMS J-2D, Table 6.

4. Piping Material Service Specification (PMSS) per GEMS J-2D, Table 7.

5. Insulation type, thickness, and heat tracing.

6. Line service or fluid handled.

7. Line origin.

8. Line termination.

9. Process design flow rate.

10. Maximum sustained operating pressure.

11. Maximum sustained operating temperature.



12. Line design pressure.

13. Line design temperature.

14. Line design minimum temperature.

15. Occasional (short term) pressure rating, if used.

16. Occasional (short term) temperature rating, if used.

17. Pipe material.

18. Pipe wall thickness or schedule.

19. Corrosion allowance.

20. Pressure test fluid and test pressure.

21. Remarks.

4. LINE SIZING

4.1 General

1. Lines shall be sized for the most economical overall design.

2. Effects of line loss, pump characteristics, and heat exchanger andcontrol valve pressure drops shall be considered. Final design shallbe based on largest total pressure drop consistent with economy,ease of operation, and noise abatement.

4.2 Sizing Criteria

1. Unless otherwise limited, maximum line velocity shall be governed bysuch factors as erosion and noise.

2. Apparent velocities of vapor-liquid mixtures shall not exceed:

V = 100/ E

V = Velocity (fps) at flowing conditions

E = Density (lb/cf) at flowing conditions

3. Velocities of process fired heater tubes shall not exceed:

V = 200/ E

V = Velocity (fps) at flowing conditions

E = Density (lb/cf) at flowing conditions

4. Velocities of streams, such as hydroprocessing reactor effluentdownstream of water injection point(s), identified to be corrosiveand/or erosive shall not exceed 20 fps.

5. Steam and water line limiting conditions shall conform to Sections4.3.1 and 4.3.3.

6. Surging in two phase mixture (e.g., vapor-liquid) lines shall beprevented. Vertical risers shall be avoided or minimized and shallnot be pocketed.

7. Heater transfer lines shall have a minimum apparent velocity asfollows:



V = 60/ E

V = Apparent velocity (fps) at flowing conditions

E = Apparent density (lb/cf) at flowing conditions

8. If there is a possibility of vapor entrainment in a liquid draw-offline, line be sized for liquid-vapor mixture. Volume and density ofmixture shall be assumed to be equal to that resulting from a volumeof vapor equal to volume of liquid.

9. Solid-liquid and solid-vapor lines shall be sized to preventstratification. If specific data regarding such mixtures is criticalto design, such information will be furnished by Purchaser uponrequest.

4.3 Specific Services

4. 3 .1 Steam Lines

1. Continuously operating steam lines shall be designed for areasonable total pressure drop.

2. Except for very short branch lines (such as lines from piperack to turbines), total pressure drop of continuouslyoperating steam lines shall not exceed the limits listedbelow:

Steam Pressure Velocity Pressure Drop

50 psig and under 10,000 fpm 0.4 psi/100 ft

Greater than 50 psig

(Sat. Stm.) 7,000 fpm 1.0 psi/100 ft

Greater than 50 psig

(Supht. Stm.) 10,000 fpm 1.0 psi/100 ft

3. Size and number of snuffing steam nozzles to heatercombustion chamber shall be calculated by heater Supplierin accordance with GEMS H-1M. Cross sectional area of steamsupply line from main steam header to nozzles shall beequal to sum of cross sectional area of all nozzles.

4. 3 .2 Steam Pressure Reducing Stations

1. Steam reducing and desuperheater station piping arrangement,location, control valve type, and size shall:

a. Be optimized for control requirements.

b. Not cause excessive noise or vibration under minimum,normal, or maximum design operating conditions.

2. Noise levels shall conform to GEMS G-4D.

3. Single or dual reducing stations, as specified, shall beprovided between each main steam pressure level system. Amanual bypass arrangement shall be provided on singlestation arrangements only.

4. Control valves shall be rigidly supported.

5. Steam velocities for pressure reducing station piping shallbe less than those shown in Section 4.3.1 and shall notexceed 7,000 feet per minute at maximum design flow rates.

6. Control valves and associated piping shall be designed suchthat approach and exit velocities are kept low.



4. 3 .3 Water Lines

1. Pressure drop in water lines may be computed on the basisof “Cameron Hydraulic Data Book”, with total pressure dropconsistent with available head.

2. Velocity of Suction Lines

a. Service conditions below 150°F and below 5000 gpm shallconform to general criteria in Section 4.1.

b. Boiler feedwater, all steam condensate, and waterexceeding 150°F shall not exceed 3 fps.

c. For flow rates of 5000 to 30,000 gpm, individual pump orbranch suction shall be limited to 5 fps. Common suctionheader shall be limited to 3 fps.

d. For flow rates greater than 30,000 gpm, appropriatevelocity shall be determined by engineering analysis.

3. Velocity of Discharge Lines

a. Lines less NPS 18, except firewater and otherintermittent service, shall be limited to 7 fps.

b. Lines greater than or equal to NPS 18, all firewater,and intermittent service shall be limited to 9 fps.

4. 3 .4 Pressure Relief Lines

Pressure relief valve inlet and outlet lines shall be sized inaccordance with GEMS K-2D and K-3D.

4. 3 .5 Instrument Air Supply Systems

Instrument air supply systems shall be sized in accordance withGEMS K-19D.

4. 3 .6 Sewer Systems

Sewer systems shall be designed in accordance with GEMS J-3D.

4. 3 .7 Acid Lines

To minimize corrosion, maximum velocity in concentrated acidlines shall not exceed 2 fps.

4.4 Minimum Line Size

4. 4 .1 Underground Lines - Outside Unit Limits

1. Category D (ASME B31.3) fluid service lines shall as aminimum be NPS 1.

2. Other lines shall as a minimum be NPS 3. Lines that runbetween adjacent units may be a minimum NPS 1 1/2.

4. 4 .2 Underground Lines - Inside Unit Limits

1. Unless specified otherwise, lines that handle chemicals orhydrocarbons shall not be run underground.

2. Utility lines shall as a minimum be NPS 1.

3. Sewer lines shall be sized in accordance with GEMS J-3D.

4. 4 .3 Overhead Lines

Except for lines for instrument leads, steam tracer supply andcondensate piping, and piping indicated on standard drawings



for special applications, overhead lines shall as a minimum beNPS 1.

4. 4 .4 Minimum Small Size Connections

Minimum size of small connections between header attachment andfirst block valve shall conform to applicable PMSS or GEMS J-2D.

5. EQUIPMENT LOCATION AND ACCESSIBILITY

5.1 Definitions

5. 1 .1 General

1. The limits described in this sections shall be observed iflocation and accessibility are specified, unless either:

a. More restrictive limits are specified (in this or otherspecifications) for individual pieces of equipment.

b. Engineering warrants special consideration for abnormalconditions, such as equipment located in pits orcongested areas.

2. “Grade” in this specification means the high point in pavedareas and actual elevation at the point involved forunpaved areas.

5. 1 .2 At Grade

1. Mechanism or part to be operated, serviced, or maintainedshall be neither less than 6 inches nor more than 7 feetabove grade.

2. An elevation of 4 feet above grade is a convenient workingelevation and shall be maintained as closely as theconfiguration of piping will permit.

5. 1 .3 Accessible for Operation from Grade

Mechanism or part to be operated shall be no more than 7 feetabove grade.

5. 1 .4 Accessible from Grade

Mechanism or part to be operated, serviced, or maintained shallbe 14 feet or less above grade without obstruction above,alongside, or below which would prohibit maintenance from aportable ladder or a scaffold.

5. 1 .5 On a Platform

Equipment or part shall be:

1. Entirely within perimeter of platform.

2. Neither less than 6 inches nor more than 7 feet aboveplatform.

5. 1 .6 Accessible from a Platform

1. Equipment or part shall be located for convenientoperation, servicing, or maintenance either on, next to, orabove a platform.

2. Where equipment or part is located next to a platform,center of operating mechanism shall be no more than 1 foot6 inches outside of handrail and neither more than 5 feet



nor less than 6 inches above platform.

3. Where equipment or part is located above a platform, top ofmechanism shall be neither more than 7 feet nor less than 6inches above platform.

5. 1 .7 Accessible from a Permanent Ladder

Mechanism or part to be operated, service, or maintained shallbe no more than 3 feet from centerline of a permanent ladder.

5. 1 .8 Accessible for Operation

Equipment shall be either:

1. Located at grade.

2. Accessible for operation from grade.

3. On a platform.

4. Accessible from a platform.

5. Accessible from a permanent ladder.

5.2 Accessibility of Valves

5. 2 .1 General

1. Convenient operation from grade shall be preferred.

2. Block valves in lines shall be located as low as possiblewithout deviating from normal piping configuration.

3. Accessibility requirements described in Section 5.2.2 shallbe met. See typical drawings for specific services.

5. 2 .2 Accessibility Requirements

1. Unless excluded by GEMS G-2D, block valves and check valvesat vessel nozzles and relief valves shall be located on aplatform.

2. Operating valves, emergency valves, and unit limit blockvalves shall be accessible for operation from grade, belocated on a platform, or be accessible from a platform.Actuated valves that are remotely operated shall beaccessible from grade or from a platform.

3. Except as otherwise noted, the following block valves orvalves associated with instruments listed below shall beaccessible for operation:

a. Displacement level instruments.

b. Gauge glasses.

c. Other instrument block valves.

4. Valves in underground lines with any of the followingcharacteristics shall be located in a valve box (Drawing9S-8161) for access:

a. Valves that require periodic blinding.

b. Valves in steam, condensate, and corrosive chemicalservice.

c. Battery limit water line block valves (all services),including their unit side drain valves and instrumentconnections (see Drawing 1S-1784).



5. If conditions other than those listed in paragraph 4.exist, valves in underground lines shall be buried in earthand made accessible as follows:

a. A hand wheel shall be located above grade with anextension stem.

b. A vertical pipe sleeve from 6 inches above grade tobonnet that is large enough in diameter to accommodateextension stem connector for valves in unpaved areas andpermit access for tightening of packing gland bolts forvalves in concrete paved areas shall be provided.

c. Pipe sleeves may be reinforced concrete, cast iron, orsteel (standard wall minimum).

d. Gear boxes for gear operated valves shall be locatedapproximately 3 feet above grade with a housed extensionstem.

5.3 Instrument Location and Accessibility

5. 3 .1 General

1. Instruments that are required to be located in relation toa platform shall be located at platforms used for otherpurposes.

2. If no platform is available at desired location, apermanent platform shall be provided.

5. 3 .2 Pressure Relief Valves

Pressure relief valves shall be accessible from grade or on aplatform.

5. 3 .3 Control Valves

1. Control valves shall be located at grade or on a platform.

2. Top of valve positioner shall not be more than 6 feet abovegrade or a platform.

3. If plug must be removed from bottom of valve, 6 inchminimum distance above grade or a platform shall beincreased to conform to valve manufacturer'srecommendation.

4. Exceptions may be made if overall dimensions of valveexceed these limitations.

5. 3 .4 Liquid Level Displacement Instruments

1. Level displacement instrument pilot mechanisms shall beaccessible from grade or a platform, except that distanceabove a platform to top of pilot mechanism case shall belimited to 5 feet.

2. Where located on a platform, necessary clearance shall beprovided in accordance with Drawing 6S-6892.

3. Where located next to a platform, center of float cageshall be no more than 1 foot outside of handrail. Face ofpilot mechanism shall be oriented such that it isaccessible and visible from platform.

5. 3 .5 Orifice Flanges (Including Block Valves)

Orifice flanges and their block valves and other flow meteringdevices shall be accessible from grade or from a platform.



Where accessible from a platform, they shall be located at anelevation that permits line mounted transmitter accessibility.

5. 3 .6 Pressure Gauges

Pressure gauges and associated valves shall be accessible fromgrade, from a platform, or from a permanent ladder or locatedon a platform.

5. 3 .7 Thermocouples, Bimetal Thermometers, and Wells

Thermocouples, bimetal thermometers, and wells shall beaccessible from grade, from a platform, or located on apermanent ladder.

5. 3 .8 Gauge Glasses and Gauge Glass Columns

Gauge glasses and gauge glass columns (and all associatedvalves) shall be accessible for operation.

5. 3 .9 Pressure Points and Block Valves In Piping

Pressure point connections and block valves in piping shall beeither:

1. Located on a platform.

2. Accessible from grade.

3. Accessible for operation from either:

a. Grade.

b. A platform.

c. A permanent ladder.

5. 3 .10 Pneumatic or Electronic Transmitters

Pneumatic or electronic transmitters for temperature, pressure,and flow shall be mounted no higher than 5 feet above grade orplatform.

5.4 Platforms

Process units shall have platforms in accordance with GEMS G-2D.

6. PIPING DESIGN AND ARRANGEMENT - GENERAL

6.1 General

1. Piping shall be fabricated and examined in accordance with GEMS J-3M.

2. Field welds in piping that passes through column lines ofstructures, foundations, platforms, or grade shall be located atleast 1 foot outside of or above such items.

3. The following bolted flanged connections shall be installed usingbolt tensioners:

a. Class 900, NPS 12 and larger, service above 500°F.b. Class 1500, NPS 8 and larger.

c. Class 2500, NPS 4 and larger.

4. Live loading (Belleville springs-washers) shall be considered forflange bolting in high temperature or cycling services that have ahistory of flange leaks.



6.2 Elevations

1. Piping within unit limits shall be located overhead, except asfollows:

a. Water lines normally non-flowing (drinking service, etc.) infreezing climates.

(1) Tops of lines NPS 20 and smaller shall be located belowfrost line.

(2) Centerline of NPS 24 and larger lines shall be located atfrost line.

b. Cooling water headers in freezing climates greater than 24 NPSshall have centerline of pipe located at frost line.

c. Drainage lines.

d. Pump suction lines that do not take suction from elevatedequipment.

e. Fire water mains.

2. Overhead lines within or adjacent to pipe racks shall be located atspecific elevations. Longitudinal and transverse lines shall belocated at different elevations. Elevations shall be selected toavoid restrictions of pipe rack space.

6.3 Change in Direction

1. Piping shall not be run diagonally except as follows:

a. For short runs close to radial equipment nozzles.

b. To simplify piping near exchanger connections.

c. To obtain substantial savings.

Long diagonal runs shall avoid elevations used for regular banks ofpiping.

2. Changes in direction shall be made with either 1 1/2 radius weldelbows, threaded or socketweld elbows (if permitted in PMSS), orpipe bends.

a. Choice of ells or bends shall be based on overall cost. However,orderly appearance of plant nor orderly spacing of pipes inpipeways shall be sacrificed to obtain savings gained by usingoccasional pipe bends.

b. If available space does not permit use of 1 1/2 radius weldelbows, short radius weld ells may be used.

3. If specified or approved by Purchaser, an overall design usinglarger radius bends (such as NPS 3 to NPS 4) may be considered if:

a. An overall savings in energy is realized.

b. It can be determined that available pipe fabrication (bending)facilities will provide competitive costs and schedules tosupport construction.

6.4 Injection Points

1. Injection of water, steam, chemicals, or other media into piping ona regular or continuous basis sometimes causes accelerated corrosionand/or erosion.

2. Selection of materials and locations and design of injection pointsshall include consideration of this phenomenon.



3. Effects shall be considered to be limited to the following:

a. Upstream limit of effects is a minimum of 1 foot or 3 pipediameters upstream of injection point, whichever is greater.

b. Downstream limit of effects is the second change in flowdirection or 25 feet beyond first change in flow direction,whichever is less.

6.5 Pockets and Dead Ends

1. Two phase lines and overhead vapor lines shall not have pockets.Pockets in other lines should be avoided. If pockets cannot beavoided, line shall have suitable drains.

2. Dead end piping shall not be used to reach a support. If necessary,dummy leg supports shall be used.

3. Dead legs shall be minimized by locating block valve close toflowing pipe for vents, drains, and other branches that are normallynot flowing.

6.6 Unit Blocks

6. 6 .1 General

1. Lines that enter or leave process unit limits shall haveblock valves.

2. Unit limit block valves in gas or vapor service, wherecondensate may freeze, shall be located in a horizontal runof line to prevent freezing of condensation during downperiods.

6. 6 .2 Air, Steam, and Water Lines

Lines from headers that service more than one unit shall haveblock valves located outside unit limits.

6. 6 .3 Overhead Process Lines

Lines crossing process unit limits shall have a block valveinside unit limits and include a drain in piping on unit sideof block.

6. 6 .4 Underground Process Lines

1. Lines crossing process unit limits shall:

a. Have a block valve located above grade at the pointwhere line enters or leaves paving.

b. Include a drain in piping on unit side of block.

Block valve provided at the pump meets this requirement forunderground suction lines to pumps located inside processunit limit.

2. Unit limit block valves shall be located in accordance withDrawing 9S-9357.

6.7 Unit Pumpout/Off Test System

1. Pumpout facilities for emergencies or normal shutdowns shall bedesigned in accordance with DP 70.

2. Product lines that must connect to off test lines shall bemanifolded inside and near unit limits.



6.8 Precommissioning

Flushing drains and break spools shall be considered forprecommissioning.

6.9 Break Joints

1. Lines connected to vessels with weld end nozzles shall have aflanged joint.

2. Flanged joint shall be used for blinding after purging and freeingline and vessel of gas to permit entry into the vessel.

3. Flanged joint may be at first flanged equipment connection away fromvessel.

4. Flanged joint shall be located to avoid high or low trapped pointsin line between joint and vessel. If possible, high point of lineshall vent back to vessel. If such venting is not possible, a valvedvent to atmosphere shall be provided.

5. Flanged joint shall be either:

a. Accessible from grade.

b. On a platform.

6.10 Winterproofing and Line Heating

1. Winterproofing shall conform to GEMS G-1D.

2. Steam tracing shall conform to GEMS J-8D.

3. Electric tracing shall conform to GEMS L-3D.

6.11 Insulation Support Rings

1. Insulated NPS 3 and larger lines that are vertical or which slope atan angle less than 60 degrees from vertical shall have insulationsupport rings.

2. Insulation support rings shall conform to Drawing 13S-378 or 13S-381.

6.12 Insulating Pipe Flanges (Electrical)

Insulating flanges for electrical isolation shall conform tomanufacturer's recommendations.

6.13 Vents in Piping

1. High points of suction lines, except those that self vent to vesselsby sloping up to towers, shall have valved vent connections to ventduring operation.

2. If air cannot be admitted to high points by other existing means,high points of lines NPS 3 and larger that must be drained shallhave valved vents.

3. High points of piping NPS 3 and larger shall have valved vents asrequired for hydrostatic testing in accordance with the following:

a. Steam lines that require hydrostatic testing shall have NPS 1threaded valves on schedule 160 nipples welded in line. Afterinitial test, nipple shall be cut to 3/4 inch in length andsealed with a weld cap.

b. Vents on other lines shall be valved, be minimum size, andconform to applicable PMSS.

4. Valved vents open to atmosphere in hydrocarbon, hydrogen, steam, or



chemical service shall have a cap, plug, or blind flange onatmospheric side of valve. Socketweld end vent valves shall have ashort pipe nipple with one end threaded and capped.

5. Where vents from equipment under pressure or piping under pressurehave extended piping downstream of block valve and more than oneturn in line and threaded fittings, line shall be supported toprevent whipping.

6. If possible, vent connections shall be located in accessiblelocations adjacent to platforms or structural members.

7. Vents located below grade on underground lines shall consist of athread-o-let, nipple, and valve. After testing is completed, nippleand valve shall be removed, and plug shall be installed and sealwelded to thread-o-let.

6.14 Drains in Piping

1. Piping systems shall have valved drains at all low points.

2. Points with no other means to drain pockets of liquid that might formabove a control or block valve shall have valved drains. Drain(bleeder) valves at control valve stations shall conform to Drawing9S-8124.

3. Unless they serve as drains for large equipment (exchangers, etc.),drains shall:

a. Be minimum size.

b. Conform to individual PMSS.

4. Drains in piping from exchangers shall be:

a. Sized in accordance with GEMS F-1M.

b. As a minimum NPS 1 1/2.

5. If a vessel requires steam-out or purging for cleaning or entry, alllines connected to vessels without a block valve at vesselconnection shall have a valved steam-out drain. To permit completepurging of line or lines with vessel, drain shall be located onvessel side of and adjacent to first block valve in the line orblock valve in each branch line.

6. Valved drains open to atmosphere in hydrocarbon, hydrogen, steam, orchemical service shall have a cap, plug, or blind flange onatmospheric side of valve. Socketweld end drain valves shall have ashort pipe nipple with one end threaded and capped.

7. Drain valves for operating drains, such as water drawoffs, or samplevalves open to atmosphere in hazardous services, such as serviceswith H2S or LPGs, shall have dead-man handles (auto close). Ifspecified drain valve is a gate valve, a ball valve shall be added.Low point piping drains shall not require dead-man handles.

8. Unit limit underground drain valves in water service shall beaccessible and terminate in accordance with GEMS G-1D.

9. Drains located below grade on underground lines shall consist of athread-o-let, nipple, and valve.

10. Unless approved by Purchaser, drain rings shall not be used.

6.15 Drain Piping (Aboveground)

6. 15 .1 General

1. Permanent piping shall be installed as described below



between drain and sewer hubs for draining:

a. Hydrocarbons C6 and heavier with temperature of 180°F orless.

b. Acids, caustics, or other chemicals for which specialsewer systems are provided.

2. Drain lines may be run to any oil sewer hub within a 15foot maximum horizontal radius of drain, provided atripping hazard is not created.

3. Piping arrangements shall not create tripping hazards orlimit access.

4. Supports for drain lines shall conform to requirements forsupports for vent lines described in Section 6.13,paragraph 5.

6. 15 .2 Vessels

1. Drains shall be valved and blinded.

2. Drains shall be piped to terminate approximately 2 inchesabove a sewer hub at grade.

3. Piping downstream of blind shall be standard weight carbonsteel (Sch. 80 for NPS 1 1/2 and smaller).

6. 15 .3 Pumps

1. Pumps in services described in Section 7.3.4 shall havecase drains piped to sewer hub located at end of pumpfoundation.

2. Construction of such piping shall conform to PMSS of pumpdischarge piping (except all welded construction as aminimum). Piping shall consist of the following:

a. Schedule 160 minimum nipple, either welded or threadedand seal welded to case.

b. Socket welded (unless PMSS specifies butt welded orflanged) valve mounted as close to pump case aspractical. API 602 extended body valve welded directlyto pump case shall be preferred.

c. Socket welded union (unless PMSS specifies flanged) forremoving drain pipe.

d. Drain pipe terminating approximately 2 inches above topof hub.

e. Threaded cap.

6. 15 .4 Compressor Cases

Drains shall be piped in accordance with Section 6.15.3 to ahub or floor drain on compressor deck or to grade.

6. 15 .5 Sample Points

Drains shall conform to Drawing 9S-9173.

6. 15 .6 Gauge Glasses, Gauge Glass Pipe Columns, and Displacement LevelInstruments

Drain piping shall conform to Drawings 9S-9166 and 9S-8125.



6. 15 .7 Elevated

1. Equipment or piping drains at elevated locations (e.g.,elevated compressor decks and condenser system structures)shall have drain piping (not directly connected to pipingor equipment drain) run from those locations to grade.

2. Drain piping shall end approximately 2 inches above sewerhub.

3. Drain piping shall be:

a. Standard weight carbon steel pipe (Sch. 80 for NPS 1 1/2).

b. NPS 1 1/2 minimum size.

4. Drain piping shall have funnels, swages, or reducers ateach level where draining is anticipated.

6. 15 .8 Unit Block Valves

1. Lines at unit limit block valves shall be drained to acollection pan or pipe trough installed and piped to asewer hub at grade.

2. Drains shall conform to Drawing 9S-9357.

6. 15 .9 Temperature Relief Valves

Temperature relief valves on process units shall have drainpiping in accordance with GEMS K-3D.

6. 15 .10 Reservoirs

Reservoirs (30 gallons or more) shall have permanent drainlines routed to sewer hubs.

6.16 Blinds

6. 16 .1 Operational Blinds

1. Operational blinds shall be supplied for the following:

a. Isolating equipment during operation of a process unit.

b. Isolating equipment for repair or inspection if wholeunit has not been gas freed.

c. Testing various sections of unit.

d. Testing equipment.

e. Preventing leakage during operations.

2. Operational blinds shall be supplied on the following:

a. Each fired heater (see Drawings 9S-9344 and 9S-9345).

(1) Fuel gas supply line to heater - line blind (Hameror Purchaser approved equal).

(2) Pilot gas supply line to heater - line blind (Hameror Purchaser approved equal).

(3) Atomizing steam to heater.

(4) Snuffing steam to heater.

(5) Fuel oil supply to heater.

(6) Fuel oil return from heater.

(7) Soot blower steam supply line.



(8) Process lines in and out of heater, including steamlines.

(9) Flue duct on each heater if duct is common to morethan one heater. These blinds shall be designed forsafe installation without entry into duct.

b. Heat Exchangers (Shell and Tube or Air Fan Coolers).

(1) Exchangers or series of exchangers in the sameservice shall have shell and tube sides blinded inand out of exchanger (or series if more than one isinvolved).

(2) Shell and tube exchangers in parallel banks shallbe blinded on shell and tube sides in and out oneach bank (see Drawing 9S-9346).

c. Compressors.

Each compressor on compressor side of suction anddischarge block valves.

d. Pumps.

Each pump, that is spared, on pump side of suction anddischarge block valves.

e. Vessels.

All lines, including steam lines, in and out of vesselat vessel nozzle. With Purchaser approval, the followingmay be excluded:

(1) Overhead vapor line from fractionator to shell andtube condenser: Blind shall be provided for alllines in and out of overhead accumulator drum suchthat fractionator-accumulator drum system can begas-freed and blinded off as a system.

(2) Overhead vapor line from fractionator to air fancondenser: Blind shall be at inlet to air fancondenser, and steam-out drain(s) shall be providedat low point in line upstream and adjacent toblind.

(3) Large FCCU catalyst lines and overhead vapor linesto fractionator.

Unless spare reboilers are provided, blinds shall not berequired on reboiler systems.

Vents and drains open to atmosphere in hydrocarbon,hydrogen, steam, or chemical service shall have a blindon atmospheric side of valve.

If a block valve or blind is not provided at vesselnozzle, a blind shall be required on vessel side offirst block valve in line. Steam-out drain at thislocation shall conform to Section 6.14.

f. Steam to hydrocarbon piping connections: Blinds shall beprovided at all points where steam lines that are notused for process or emergencies are permanentlyconnected to hydrocarbon lines. Blinds shall not berequired on steam lines that have swing ells forisolation.

g. All process lines and all lines that contain toxic or



hazardous materials which enter or leave process unitsshall be blinded as follows:

(1) Operational blinds shall be provided on unit sideof all unit limit block valves (see Section 6.6).

(2) Blinds shall be installed on pump side of blockvalve on underground suction lines to pumps, whereunit limit block valve is located at pump.

3. Figure 8 blinds shall not be installed in cold insulatedpiping systems. If piping cannot be sprung for installationof blinds, spacers shall be provided.

4. Operational blinds shall be accessible either from grade oron a platform. If access with mobile equipment is notpossible, handling davits shall be provided for all blindsor spacers weighing more than 150 pounds.

5. Exposed finished surfaces of blinds shall be greased forprotection after installation.

6. 16 .2 Piping Systems Isolation

1. A positive means of isolating interconnected piping systemsshall be provided for maintenance and testing (e.g., vents,PSV bypasses, blowdowns, and other connections betweenprocess services and flare system or utility to processpiping).

2. Isolation may be provided by double block and bleed valves,operational blinds or, for small threaded or socket weldedlines, a set of flanges.

3. If equipment of systems can be isolated without shuttingdown an entire unit, above provisions shall be provided inany interconnected lines to other equipment or systems(blowdown lines, etc.).

6. 16 .3 Construction Test Blinds

1. Blinds necessary for testing lines and equipment duringconstruction, other than those specified in Section 6.16.1shall be furnished with initial installation.

2. Such blinds need not conform to Drawing 9S-8168.

3. These blinds shall be removed from joints beforeinstallation can be accepted mechanically.

6.17 Utility Stations

6. 17 .1 General

1. Utility hose stations for steam, water, and air shall beprovided at convenient locations throughout process units.

2. Stations shall be provided at fired heaters, heat exchangergroups (including air fin coolers), tower groups, pumpgroups, at compressor, and at each main working level inelevated structures.

3. If specified, nitrogen stations shall be provided.

4. Piping shall be arranged in accordance with Drawing 9S-7413.

5. Utility stations shall be located such that no more than 50feet of hose is required to service a piece of equipment.



6. 17 .2 Air Hose Stations

1. In addition to utility hose stations, air hose stationsshall be located to permit removal of bolts from manways,exchangers, and similar large bolted connections with anair tool and not more than 50 feet of hose.

2. Manways or large bolted connections more than 20 feet abovegrade shall have a station at platform serving manway orconnection. Station shall be mounted on top of handrail.

3. Air hose stations shall not be required at remote locationswhere portable air compressors can be used for maintenance(e.g., tank farms).

6. 17 .3 Steam Hose Stations

1. Utility steam service shall have intermediate pressuresteam.

2. If normal operating pressure of steam exceeds 180 psig, a7/16 inch union mounted restriction orifice shall beinstalled immediately upstream of hose station valve.

3. Steam supply piping shall be arranged as an auxiliarybranch that can be blocked off without affectingoperations.

6. 17 .4 Hot Water Stations

1. If specified, hot water stations shall be provided.

2. Station shall have mixing devices that mix steam andservice water. Mixing devices shall manufactured by Sellersor Purchaser approved equal.

6. 17 .5 Utility Hose and Couplings

1. Hose couplings at utility stations shall conform to plantstandards.

2. Nitrogen connections shall be unique such that they cannotbe mixed with air, steam, or water.

3. Utility hose will be furnished by plant.

6.18 Instrument Piping

6. 18 .1 Connections

1. Instrument connections, including size, schedule, flangerating, and block valve specifications, shall conform toPMSS.

2. Connections not defined by PMSS or not otherwise specifiedshall conform to minimum size and schedules specified inGEMS J-2D.

6. 18 .2 Piping Details

Specific requirements for piping between instrument and itblock valve or piping associated with instruments, such asorifice runs, control valves, pressure relief valves, and gaugeglass columns, are typically defined in instrumentspecifications.

6. 18 .3 Accessibility

Accessibility shall conform to Section 5.3.



6.19 Safety Showers and Eyewash Fountains

1. Potable water safety showers and eyewash fountains shall be providedwherever hazardous chemicals, such as caustic, acid, or otherinjurious and corrosive materials, are handled. This requirementshall apply to laboratory, as well as operating areas.

2. Safety showers and eyewash fountains shall be located within 25 feetof hazardous materials area.

3. If concrete paving is not present, shower shall have 4 inch thickand 2 foot square concrete slab underneath.

4. Dimly lit areas shall have a green 25 watt electric bulb near safetyshower.

5. Shower/eyewash location shall be identified with 4 inch wide greenand white diagonal stripes painted on four sides of column or otherbackground available at that location. Striped area shall extendfrom 2 feet above grade to 6 feet above grade.

6. Eyewash fountains shall be 30 to 36 inches above grade.

6.20 Sample Connections

1. Sample connections and piping shall conform to Drawing 9S-9173.

2. Sample coolers shall be standard commercial type or, as analternate, in accordance with Drawing 9S-7412.

6.21 Clearances

6. 21 .1 General

1. Clearances shall conform to GEMS G-2D.

2. Clearances shall also conform to the following:

a. Except for special cases at manifolds and otherequipment located at grade or vessels in structures, thefollowing minimum overhead clearances shall bemaintained above high point of finished paving or aboveplatforms within process unit limits:

(1) At least 16 feet of clear headroom over areasdesignated as tube bundle handling areas forexchangers at grade, trucking areas, and roadwaysinside or adjacent to process units limits. Theminimum clearance of 12 feet x 12 feet forservicing equipment under process unit main piperacks shall be excluded.

(2) At least 6 feet 8 inches of clear headroom overplatforms and walkways. This minimum clear headroomshall also apply to piping at grade, close toequipment. The minimum of 8 feet high shall beobserved for all other horizontal piping thatcrosses process unit passage ways and workingareas.

b. For minimum lateral and vertical spacing, linessupported on sleepers at grade or on overhead pipesupports shall be assumed to have staggered flanges.Minimum line spacing shall be determined by providing atleast 1 inch of clearance between the outside of oneline flange (or flange insulation if insulated) and theoutside of adjacent line (or line insulation ifinsulated).



6. 21 .2 Exchangers

Exchanger clearances shall conform to Drawing 9S-7686.

6. 21 .3 Vessels

Vessel clearances shall conform to Drawings 6S-6892 and 6S-7257.

6. 21 .4 Pumps, Compressors, and Drivers

Sufficient space shall be provided at and around pumps,compressors, and drivers to enable maintenance and removal ofall internal and external parts.

6. 21 .5 Control Valves

1. Control valves shall be located such that front of valvemanifold as a minimum has 2 feet 6 inches of access.

2. Clearances of control valves, snuffing steam stations,etc., at fired heaters shall conform to Drawings 9S-9344and 9S-9345.

6.22 Block Valves

6. 22 .1 Emergency Block and Depressuring Valves

Emergency block valves to isolate equipment and systems or todepressure systems in emergencies shall conform to DP 70.

6. 22 .2 Branch Line Block Valves

1. Primary branch lines are branches that are connecteddirectly to main header in the pipe rack. Utility serviceprimary branch lines shall have block valves except in:

a. Services in which main header may be shut off withoutaffecting unit operation in event of failure in branchline.

b. NPS 3 and larger cooling water branches.

2. Secondary branch lines are branches that are connected toprimary branches. Utility service secondary branch lines donot require block valves except in steam service in whichsome secondary branches from a single primary branch are inintermittent service and some from the same primary branchare in continuous service. Where this occurs, intermittentservice lines shall have a branch line block valve.

3. Steam branch line block valves shall be located inhorizontal run of branch.

4. Except as specified in paragraph 5., primary branch lineblock valves shall be located at outside edge of pipe rack.Unless specified otherwise, access for operation (platformor chain wheels) shall not be provided.

5. Take-off valves shall be provided at intervals of 25 feetalong the main instrument air header in accordance withDrawing 9S-9258.

6. Steam tracer piping valves shall conform to Drawing 9S-7690.

6. 22 .3 Block Valves at Change of Specification

Block valves between lines or between lines and equipment ofdifferent services shall conform to PMSS for the most severe



service, except:

1. Valves at vessel process steam or steam-out connectionshall be of type and material required for vessel service.Resilient seats shall not be used if steam temperatureexceeds seat limitations.

2. Rating of valve shall be suitable for maximum conditiongoverned by vessel or steam conditions.

6. 22 .4 Double Blocks and Bleeder

Double block valves and bleeder shall not be used, except asfollows:

1. To prevent contamination of product. With Purchaserapproval, single positive shut-off valves with integralbleed may be substituted for double blocks and bleeder forthis service.

2. To provide back-up valve if valve on drain or vent freezesdue to vaporization of light hydrocarbon.

3. As required for pumps vents per Section 7.3.5.

4. Steam supply branches permanently connected to hydrocarbonlines.

5. If specified, vessel drain valves.

6. 22 .5 Valve Operating Devices

1. NPS 14 and larger gate valves shall have gear operators.

2. For frequently operated gate valves, gear operators forsmaller valves shall be considered as follows:

a. Class 300 - NPS 12 and larger.

b. Class 600 - NPS 10 and larger.

c. Class 900 - NPS 6 and larger.

3. Quarter turn valves shall conform to valve description.Smaller sized valves shall conform to manufacturer’sstandard or recommendations for gear operators.

4. If remote mechanical valve operating devices are required,chain operators shall be used in preference to valveextension stems on overhead valves larger than NPS 1 1/2.

5. Chain operators shall not be used on valves NPS 1 1/2 andsmaller.

6. Valves with chain operators or hand wheel extensions shallnot have threaded end connections.

7. Valve extension stems, chain wheels, and associatedsupports shall be galvanized in accordance with GEMS S-1M.

8. Valves that are required to be locked open or closed shallhave chain or bar devices for use with padlocks. Padlocksto suit master lock system will be furnished by plant.

6.23 Check Valves

1. If specified on Drawing 9S-8262, a check valve shall be providedbetween block valve and pump in discharge line of centrifugal pumps.

2. Lines which connect lines or equipment of different service withpotential of back flow of fluid or other source of backpressure that



could create a hazardous condition shall have a check valve.

3. Steam supply lines to heat exchangers shall have check valves ifmaximum operating pressure of fluid being heated is the same orhigher than steam line pressure.

4. Check valves on a line flowing into a pressure vessel shall belocated in a horizontal position, such that downstream side will beself draining into vessel.

5. Steam supply branches permanently connected to hydrocarbon linesshall have a check valve.

6. Two check valves in series shall be provided in the followingsituations:

a. Pressure differential is 750 psi or above.

b. A single check valve failure would result in a relief case.

c. A single check valve failure could destroy mechanical equipmentthrough unrestricted reverse flow.

6.24 Pipe Plugs

Pipe plugs in tapped connections in piping and equipment that are notrequired to be removed during operation and maintenance shall be sealwelded in hydrocarbon, hydrogen, chemical, and steam services.

7. PIPING DESIGN AND ARRANGEMENT - SPECIFIC SERVICES

7.1 Vessel Piping

7. 1 .1 General

Vessel piping shall conform to Drawings 6S-6892 and 6S-7257.

7. 1 .2 Block Valves at Vessel Nozzles

1. Except for pressure relief valve nozzles, block valvesshall be installed adjacent to vessel on all nozzles NPS1 1/2 and smaller and on all steam, air, water, vent,drain, and instrument connections, regardless of size.

2. Block valve requirements at pressure relief valves aredefined in GEMS K-2D.

3. Pressure relief valves bolted directly to vessel blockvalves shall be readily removable without need for removalof block valves from vessel. Otherwise, a spool piece shallbe furnished between pressure relief valve and block valve.

4. Double block valves, with intermediate bleed for checkingleakage or blowing out clogged drain nozzle, may bespecified for towers.

5. Unless specified otherwise in paragraph 1., block valvesshall not be required in lines or at vessel nozzles for thefollowing lines:

a. Vapor lines to condensers.

b. Liquid and vapor lines to and from shell and tubereboilers.

c. Lines from condensers to accumulator drums.

d. Large special FCCU catalyst lines.

e. Block valve requirements in fired heater outlet transfer



lines to vessels are defined in Drawing 9S-9344.

f. Block valves in pump suction lines are defined inSection 7.3.2.

6. Valves or flanges shall not be located inside a vesselskirt.

7. Valves at vessel nozzles shall be flanged valves, except inservices that permit threaded couplings for vesselconnections defined by GEMS F-1M.

7. 1 .3 Steam-out Connections

1. A separate steam-out connection shall be provided tointroduce steam for purging at down periods, except:

a. Vessels in air, steam, and water service.

b. Vessels provided with process steam. For this case,minimum size of vessel connection shall conform toDrawing 9S-7165.

c. Special vessels with process considerations that requireother means of purging or prohibit use of steam.

2. Steam-out connections shall be sized and installed inaccordance with Drawing 9S-7165.

3. Type and rating of valves at steam-out connections shall bein accordance with Section 6.22.3.

4. Snuffing steam requirements for pressure relief valvesdischarging to atmosphere shall conform to GEMS K-2D.

7. 1 .4 Process Steam Connections

Process steam connections shall conform to Drawing 9S-7165.

7.2 Heat Exchanger Piping

7. 2 .1 General

1. Piping for shell and tube exchangers shall be arranged inaccordance with Drawing 9S-7686.

2. If necessary for bundle puller clearance, a removablesection of piping shall be provided at bottom of shell andtube channel connections.

3. Dimensional design requirements for standard plant bundlepuller shall be provided to engineering contractor.

7. 2 .2 Shell and Tube Coolers and Condensers

1. Cooling water and backwash piping shall conform to Drawing9S-9175.

2. Backwash piping shall not be required for cooling watersystems, such as closed tempered water and closed jacketwater systems.

7. 2 .3 Shell and Tube Heaters (Steam)

Steam and condensate piping for shell and tube heaters shallconform to Drawing 9S-9172.

7. 2 .4 Parallel and Spare Exchanger Systems

Piping for air coolers and shell and tube exchangers thatrequired isolation during operations shall conform to Drawing



9S-9346.

7. 2 .5 Vents and Drains

1. Except for vents and drains in shell and tube exchangersper Drawing 9S-7581, venting and draining shall beaccomplished in associated piping.

2. Exchanger operating vents and shell cover drains open toatmosphere shall be valved and blinded. Non operatingnozzles that were provided in channel, shell, and headerbox shall be blinded for testing.

7.3 Pump Piping

7. 3 .1 General

1. Piping arrangements at liquid end of pumps shall conform toDrawing 9S-8262.

2. Sufficient space shall be provided at and around pumps toenable maintenance and removal of all internal and externalparts.

3. In hydrocarbon or other flammable fluid service, threadedconstruction shall not be used for piping connected topump, including branch piping within 6 feet of pump suctionor discharge flanges or through suction or discharge blockvalves, whichever is greater. Socketweld unions areacceptable.

4. Except for check valve drains specified on Drawing 9S-8262,all NPS 1 1/2 and smaller connections in piping within 6feet of pump shall be made with self-reinforced fittings(sock-o-lets, weld-o-lets, or equal).

5. If high differential pressure may cause reverse flow anddamage to rotary equipment, two check valves in series maybe considered.

6. Precautions in Section 7.4.2 shall apply.

7. 3 .2 Suction Piping

1. Centrifugal pump suction lines from tankage shall bearranged to be self venting to tank, pump, or both.

2. Pump suction lines shall have a block valve as close aspractical to pump nozzle or swage at pump nozzle. UnlessNPSH calculations show a smaller valve is suitable, valveshall be full line size.

3. If suction side can be subjected to discharge pressure byleakage through discharge check valve, pump suction blockvalves and piping to pump shall have a pressure class orrating equal to discharge piping. This can occur if two ormore pumps discharge into a common header.

7. 3 .3 Discharge Piping

If block valve is located at pump nozzle in discharge linesfrom single service pumps, valve may be same size as pumpdischarge nozzle, provided velocity through valve does notexceed 11 fps.



7. 3 .4 Pump Case and Cylinder Drains

Case drains shall be provided in accordance with Section 6.15.3for liquids toxic or injurious to personnel and liquids subjectto freezing or set up at or above minimum ambient temperatures.

7. 3 .5 Pump Vents

1. All pumps shall have a valved vent.

2. Vent connection for pumps with top discharge nozzles shallbe in pump discharge piping between pump and first valve. Other pumps shall have valved vent connected to top of pumpcase.

3. Valved vents shall be piped as follows:

a. If vapor pressure of pumped hydrocarbon is greater thanatmospheric pressure at pumping temperature, vents shallbe piped to a closed system as follows:

(1) Vent piping shall be connected to flare system.Purchaser shall be consulted regarding disposal ofhighly viscous materials that could foul flaresystem in cold climates.

(2) In absence of flare system, Purchaser shall beconsulted regarding disposal.

(3) Vents to closed systems shall have double blockvalves and intermediate bleeder at pump connection.

(4) Vent piping shall be connected into top of closedsystem header.

b. If vapor pressure of pump hydrocarbon is less thanatmospheric pressure at pumping temperature or for pumpshandling non-hydrocarbon materials, vents shall be pipedto drain hub of appropriate sewer. Toxic, valuable, orhazardous materials or materials pumped at high pressureor temperature shall receive special consideration.

c. If suction pressure is below atmospheric pressure, suchas vacuum residuum service, vents shall be piped tovessel from which liquid is being pumped, unless pumpnozzles are arranged such that pump case will vent backto vessel through suction piping. If necessary vent lineshall be steam traced for viscous liquids.

7. 3 .6 Suction Strainers

1. Temporary Strainers

a. Suction of all pumps shall have temporary line strainersbetween pump suction flange and block valve.

b. Design shall allow removal of spool piece if pump isblocked in.

c. If a flanged spool piece exists in piping configurationthat will contain and/or permit removal of a basketwithout additional pipe fittings, basket type strainersshall be provided.

d. Temporary strainers shall be installed before start-upand shall be removed following start-up.

e. Basket type temporary strainers shall as a minimumprovide an open area that is 150% of cross sectional



area of suction line (not pump connection).

f. Temporary strainers shall be carbon steel unless carbonsteel is not expected to serve satisfactorily for ashort time (start-up).

2. Permanent Strainers

a. If permanent pump suction strainers are necessary, suchas in oil-catalyst slurry lines and coking service,strainers that can be cleaned in place shall bedesigned.

b. If required, permanent strainers shall be installedbetween pump suction block valve and pump.

c. Material for permanent strainers shall meet or exceedapplicable service conditions and be at least equal incorrosion resistance to pipe material.

7. 3 .7 Cooling Water

Cooling water piping manifold for pumps, gears, and turbinesshall conform to Drawing 9S-8200.

7. 3 .8 Product Recirculation

Pumps with minimum flow less than that allowed by pump designrange shall have recirculation piping from pump discharge tosuction vessel for heat dissipation.

7.4 Compressor Piping

7. 4 .1 General

1. Sufficient space shall be provided at and aroundcompressors to enable maintenance and removal of allinternal and external parts.

2. In hydrocarbon or other flammable fluid service, threadedconstruction shall not be used for piping connected tocompressor, including branch piping within 6 feet ofcompressor suction or discharge flanges or through suctionor discharge block valves, whichever is greater. Socketweldunions are acceptable.

3. NPS 1 1/2 and smaller connections in suction and dischargelines within 6 feet of compressor shall be made with self-reinforced fittings (sock-o-lets, weld-o-lets, or equal).

4. Distance between suction knockout drums from each stage andcompressor shall be minimized.

5. Low spots in piping between knockout drum(s) and compressorshall be avoided. Piping shall be sloped such that itdrains condensation back to drums. Deviations shall besubject to Purchaser approval. To collect and dispose ofliquid that may be present in the line, a vane-typeseparator or coalescer shall be installed at all lowpoints.

7. 4 .2 Thermal Expansion and Vibration

1. Gas compressor headers shall be suitably arranged andproperly anchored for thermal expansion and vibrationabsorption.

2. Minimum natural frequency of separate structures or anchorsshall be 10 times maximum rpm of compressors.



3. Suction and Discharge Lines and Their Support Systems

a. Design shall be such that natural frequency of pipingsystem does not respond to forcing frequency ofequipment under all modes of operation up to andincluding fourth harmonic of piping system's naturalfrequency.

b. Particular attention shall be given if using shortradius fittings or other restrictions that may causevibration of piping system due to acoustics of pipingand its contents.

7. 4 .3 Strainers

1. Except for compressors that take suction through a filterlocated close to compressor, suction line of allcompressors shall have a temporary line strainer.

2. Strainer shall be located between block valve andcompressor.

3. Strainer shall have a free flow area not less than 150% ofpipe area. Pressure drop shall not exceed amountpermissible in compressor design.

4. Strainer support ring and/or stiffeners shall be carbonsteel. Strainer mesh shall be 304 stainless, 10 x 10 with1/32 inch wire.

5. A removable flanged spool piece or other suitable meansshall be provided for easy installation and removal ofstrainer.

6. Suction piping immediately upstream and downstream ofstrainer shall have valved pressure taps. Taps shall bemanifolded to a pressure gauge such that either pressurecan be read.

7. Strainer shall be installed in new installations and shallbe reinstalled after subsequent maintenance or changes tocompressor suction line.

8. Strainers shall be retained in line for minimum timerequired to ensure a clean suction line. This period shallnot normally exceed time required for first run.

7. 4 .4 Snubbers

Snubbers (bottles or dampeners), if required in compressor,shall be designed in accordance with ASME B31.3.

7. 4 .5 Internal Pipe Cleaning

1. Field internal pipe cleaning procedures shall conform toGEMS J-2P.

2. If cleaning of compressor suction piping is necessary,particularly for non-lubricated type reciprocatingcompressors, the following shall be considered:

a. Pickling in fabricator’s shop may require fabrication inflanged spools to avoid field welding after pickling.Other cleaning methods, such as mechanical cleaning ofwelds and weld spatter, hydroblasting, or grit blasting,shall be considered.

b. Pickling after erection in field shall require extracare to ensure that all low points are completely



drained of pickling agent.

c. Piping shall be tested prior to cleaning or aftercleaning with suitable, non-rusting liquid.

d. After cleaning, piping shall be protected from rustingprior to start-up of compressor.

3. Lube, seal, flushing, and hydraulic oil piping systemsshall be designed and purchased to maximize internalcleaning prior to delivery to job site.

4. Interconnected piping between skids, consoles, and machinesshall be designed for separate cleaning prior to assemblyof system.

7. 4 .6 Check Valves

1. Discharge check valves for reciprocating compressors shallbe non-slam type.

2. Discharge check valves, including those in spillback andbypass lines, shall be sized in accordance with all designcases, especially low flow cases.

7. 4 .7 Blower Discharge Piping

1. Centrifugal air blowers that manifold into a commondischarge line shall have an atmospheric, silenced vent ineach blower discharge line.

2. Each line shall also have a check valve.

7.5 Fired Heater Piping

7. 5 .1 General

Fuel systems, process control, and heater shutdowns shall bedesigned in accordance with Drawings 1S-1856 through 1S-1863.

7. 5 .2 Fuel Gas and Fuel Oil Piping

1. Fuel gas and fuel oil piping shall conform to Drawing 9S-9345.

2. Unless approved by Purchaser, flexible hose shall not beused in lieu of fixed pipe to fuel gas or fuel oil burners.

3. If rigid piping will place undue strain on burner,Purchaser will consider approval of flexible hose. Ifapproved, flexible metal hose shall be 316 SS with externalsingle woven wire braid.

7. 5 .3 Process Piping

1. Process piping shall conform to Drawing 9S-9344.

2. If there is liquid or two-phase flow at heater outlet anddesign requires manifolding or outlet connections in acommon header, branches shall enter header at 45° or less.

7. 5 .4 Steam-out Manifolds

Steam-out manifolds shall conform to Drawing 9S-9344.

7. 5 .5 Decoking and Catalyst Regeneration

1. Heater decoking manifolds shall conform to Drawing 9S-9347.

2. Removable pieces shown on Drawing 9S-9347 shall be locatedat grade or on a platform.



3. Manifolds or other valves shall not be located near catchbasin into which effluent is discharged.

7. 5 .6 Location of Instruments

All instruments and instrument connections shall be located ata minimum distance of 50 feet from shell of fired heaters,except direct connected pressure gauges, draft gauges,thermocouples, damper operators, stack sample connections,flame scanning, and ignition systems.

7.6 Relief System Piping

7. 6 .1 General

1. Relief system shall be designed in accordance with GEMS G-5D and Drawing 1S-1781 (two sheets).

2. Piping for relief valve inlet and discharge shall bedesigned in accordance with GEMS K-3D.

7. 6 .2 Connections to Header

1. Connections shall be to top of flare header, normally at90°.

2. If problems, such as layout limitations or velocity, exist,connections at 45° may be considered.

7. 6 .3 Isolation

Isolation between flare header and connecting piping shallconform to Section 6.16.2.

7. 6 .4 Relief Valve Piping

1. Relief valve discharge piping shall be self draining (nopockets) from relief valve into flare header.

2. Deviations shall be subject to Purchaser approval.

3. Header shall be sloped a minimum of 1/16 inch per foot tounit knock-out drum.

4. Discharge piping open to atmosphere shall:

a. Be galvanized.

b. Have an NPS 3/4 low point drain piped to a safelocation.

5. Open end of discharge piping shall be covered by screen orhinged flap to prevent entry by birds.

7. 6 .5 Valves

1. Unless pressure drop is considered for line sizing, inletand outlet block valves for relief valves, except TSVs,shall be full port valves. API 600 valves are full port.NPS 1 and NPS 2 valves shall be specified full port orchecked.

2. Gate valves and butterfly valves shall be oriented suchthat valve stem is in a horizontal position.

3. Unless flare system will be shut down with process unit,main header at process unit limits and offsite drum shallhave flare knockout drum isolation valves. Valves shall beV-900E4 butterfly valves.



7. 6 .6 Flare Header Support

1. Supports for headers inside process unit limits to blindinglocation downstream of unit knockout drums shall bedesigned for hydrotest.

2. Supports for offsite flare headers shall be designed forpneumatic testing.

3. A blinding location shall be required at or near base offlare stack.

7.7 Steam and Condensate Piping

7. 7 .1 Headers and Branches

1. Steam piping to all units and to equipment groups locatedeither inside or outside of unit limits shall be arrangedin separate sub-header supply systems provided with blockvalves at connections into the main.

2. Branch line connections into horizontal steam lines shallbe made in top of line, except as permitted for steamtracer sub-branches per Drawing 9S-7690.

3. Steam branch lines to offsite areas, such as tank farms,cooling tower pumps, and docks, shall have block valves atpoint of takeoff from main lines to permit isolation formaintenance.

4. Additional block valves shall be installed in main linesand branch lines defined in paragraph 3., if steam line islong and has several widely spaced lines off main or branchheaders.

5. Steam trap shall be installed before each block valvedefined in paragraph 4.

6. Steam supply piping to steam tracers shall be arranged inaccordance with GEMS J-8D.

7. 7 .2 Steam Gate Valve Bypasses

1. If length of line downstream of gate valve exceeds 150feet, valved (throttling type) bypasses shall be providedas follows:

Gate Valve Size Bypass Line and Valve Size - NPSNPS 0-50 psig 51-425 psig 426-1550 psig

6 - - 1 8-10 - 1 1*12-20 - 1 1*24 4 1 1*30 and up 6 1 1

* NOTE - If downstream line length exceeds 400 feet andsteam pressure is greater than 50 psig, gate valves NPS 12and larger shall have one NPS 2 valve. Bypass for mainplant steam distributing lines that cannot be shut downwithout shutting down several process units shall have twovalves.

2. If possible, bypass connections shall be in piping adjacentto valve.

7. 7 .3 Steam Separators

1. Steam separators, where required in steam lines to steam



drivers, shall preferably be horizontal type.

2. If required by piping layout, steam separators may bevertical type.

3. Material shall conform to material shown for block valvesin individual PMSS.

7. 7 .4 Piping to Pumps and Turbines

1. Steam piping to pumps and turbines shall conform to Drawing9S-8261.

2. Sufficient space shall be provided at and around driversfor pumps and compressors to enable maintenance and removalof all internal and external parts.

3. Expansion joints, if used, shall be packless and corrugatedtype, suitable for maximum design pressure of steam system.

4. Control valves for steam turbines (except for scavengertype) shall be located as follows:

a. Control valves (regardless of size) for automatic start-up turbines shall be located at grade adjacent toturbine or pump.

b. Control valves (NPS 6 and smaller) for manual start-upturbines shall be located at grade adjacent to turbineor pump.

7. 7 .5 Steam Traps

Steam traps and associated piping shall be designed inaccordance with GEMS J-6D.

7. 7 .6 Steam Condensate Systems

1. Overhead steam condensate collecting systems shall beprovided to collect condensate from all traps withinprocess unit areas. Condensate shall be handled in thefollowing order of preference:

a. Condensate shall be discharged from individual steamheader traps to the next lower pressure steam system ifavailable in area and if sufficient differentialpressure exists between steam systems to ensure propertrap operation.

b. If a condensate collection system is provided on unit,trap condensate shall be discharged directly to thatsystem.

c. Trap condensate shall be discharged into cooling towerwater return system.

2. Separate steam condensate collecting systems are preferredto collect condensate from each different pressure steamsystem on process unit. Condensate streams with temperaturedifference greater than 40°F shall not be collected in sameheader.

3. Each separate condensate collecting system on process unitshall generally consist of a main header with connectingsubheaders running to areas in which traps are located.Steam connection shall be provided at end of condensateheader. Connection shall be used for warmup steam and asbleed steam to reduce header knocking.



4. Condensate subheaders and main header shall be routed,without pockets, to a condensate flash drum venting to nextlower pressure steam system, if sufficient pressure isavailable, or to atmosphere, if sufficient pressure is notavailable. Flash drum liquid shall be pumped back to boilerarea.

5. Condensate collecting systems shall be designed to avoidexcessive back pressure on traps. Sizing such condensatesystems shall consider the following:

a. Flashed steam produced when traps discharge.

b. Continuous blowing of traps caused by faulty operationor insufficient condensate to seal trap against steamleakage.

c. Back pressure at trap discharge.

6. Condensate shall be collected from steam traps outsideprocess unit limits, if practical.

7. Condensate loads at individual steam traps shall bedetermined in accordance with GEMS J-6D.

7. 7 .7 Steam Lines to Atmosphere

1. Steam relief valve discharge lines and blowdown lines toatmosphere shall be galvanized.

2. Low point of line shall have NPS 1 female threaded fitting.

3. Piping shall conform to GEMS K-2D.

7.8 Air Piping

1. Branch line connections from horizontal headers shall be in top ofheader.

2. Air lines permanently connected to process lines shall have apositive means of back flow prevention in addition to a check valveper Drawing 9S-9367.

3. Instrument air supply piping shall conform to GEMS K-19D.

7.9 Water Piping

7. 9 .1 General

1. Potable water connections shall be provided for:

a. Drinking.

b. Ablutionary.

c. Culinary.

d. Eyewash.

e. Safety showers.

f. Sample sinks.

g. Wash up (inside buildings).

2. Each piece of equipment connected to potable water systemshall have an isolation valve.

3. If approved by Purchaser, toilets and urinals in remotelocations may have non-potable water.



7. 9 .2 Cooling Water on Process Units

1. Offsite cooling water shall conform to Section 7.12.

2. Each branch of cooling water supply and return lines shallhave block valves to permit independent shutdown of eachpiece of equipment or bank of coolers.

3. An NPS 1 1/2 bypass shall be provided between end of supplyand return headers on overhead cooling water lines infreezing climates.

4. Details of cooling water piping to pumps and turbines shallconform to Drawing 9S-8200. Branch line takeoffs for pipingincluded in the drawing shall be made in top of coolingwater supply header.

7. 9 .3 Drains

All water lines shall have drains to drain above grade portionof lines.

7. 9 .4 Fire Water

Fire protection system shall be designed in accordance withGEMS M-3D.

7. 9 .5 Piping for Hydrostatic Test

1. After initial hydrostatic test for vessels, lines, andequipment, it shall be assumed that future fillings fortests will be by hose.

2. Supply lines used for test water shall have an NPS 2 valvedconnection not more than 50 feet from any vessel.

3. Water for testing shall conform to GEMS J-1P.

4. Valves in freezing climates shall be hydrant type.

7. 9 .6 Valve Bypass (Hot Process Water)

If hot process water exceeds 500 psig and/or 450°F, valvedbypasses around all gate and globe valves shall be provided forwarm-up circulation in accordance with Section 7.7.2.

7.10 Oxygen Service Piping

1. Oxygen service piping shall be designed in accordance with CGAPamphlet G-4.4.

2. Material shall be selected in accordance with GEMS J-2D.

3. Internal cleaning of piping shall conform to GEMS J-2P.

4. Design of piping shall consider cleaning requirements.

5. Piping shall have adequate vents, drains, and capability tocirculate chemicals.

6. Elevation changes shall be minimized.

7.11 Underground Piping

7. 11 .1 General

1. Underground lines shall be buried in well tamped earth.

2. Piping shall not be located under buildings.

3. Pipe enclosed in Gilso-Therm or similar material shall bedesigned for pressure and temperature of curing medium for



insulation, if curing is required.

4. Lines crossing roads or railroads that do require sleevesshall as a minimum have 12 inches of cover between top ofpipe and top of road and/or bottom of railroad ties.

5. Design shall consider maximum temporary construction loads.

7. 11 .2 External Coating and Cathodic Protection

1. Ungalvanized carbon steel pipe (buried in soil or sand)with normal operating temperature of 150°F or less shall beprotected by an external coating.

2. Pump out, emergency, and drain lines with indeterminatenormal operating temperature shall, for coating purposes,be considered to be 150°F or below.

3. Unless specified otherwise, lines above 150°F shall nothave external protective coating.

4. External protective coating for manual and machineapplication shall conform to GEMS J-6M.

5. Necessity, extent, and type of cathodic protection shall bedetermined for each project in accordance with location,service, and plant experience. Cathodic protection, ifrequired, shall conform to GEMS L-2D.

7. 11 .3 Sleeves

1. General

a. Sleeves shall be sized at least 2 nominal pipe sizeslarger than protected line.

b. Sleeves shall provide ample installation clearance forthe greatest outside diameter of bells, hubs,insulation, etc.

c. Sleeves shall have a minimum cover of 6 inches betweentop of sleeve and bottom of railroad ties or top ofroads not paved with concrete. On concrete paved roads,minimum cover between top of sleeve and bottom ofconcrete shall be 3 inches.

d. Pipes in sealed sleeves shall be centered with suitablecentering devices.

2. Sleeves for Bare Lines

Bare lines under temporary and permanent roads and railroadspur tracks shall have pipe sleeves as follows:

a. If required by governmental regulations or railroadeasements.

b. If size is NPS 12 or smaller and distance between top ofline (outside of bells) and bottom of railroad tiesand/or surface of road at low point is 12 inches or lessand lines are any of the following:

(1) Cast iron or concrete.

(2) Pipe of any material crossing under concrete pavedroads and main plant roads (paved or unpaved).

(3) Pipe of any material in extremely hazardouslocations where hot work is impractical.



c. All line sizes, regardless of depth below surface, iftemperature exceeds 150°F.

d. Non-metallic lines (except concrete and other non-metallic sewer lines).

e. Vital main roads, extremely hazardous locations,concrete paved roads, and special requirements shall bespecified by project.

3. Sleeves for Insulated Lines

a. Underground insulated lines (except lines insulated withGilso-Therm or similar materials) shall have pipesleeves, regardless of size and depth below surface.Sleeves shall be sealed, or other means shall beprovided to prevent entrance of water.

b. Insulated lines which pass through tank farm dikes shallhave pipe sleeves. A fire resistant seal shall beprovided between pipe and sleeve at outside face ofdike. Sleeve shall be sloped towards the inside.

7. 11 .4 Sewers

Sewers shall conform to GEMS J-3D.

7. 11 .5 Flanged and Threaded Connections

1. Except at flanged valves located in valve boxes, buriedhydrocarbon, acid, or caustic lines inside of unit limitsshall not have flanged or threaded connections.

2. Except at flanged valves located in valve boxes, buriedhydrocarbon and caustic lines outside of unit limits shallnot have flanged or threaded connections. If welding is notpermitted, hydrocarbon lines may be connected to existinglines with flanged or threaded flanged connections.

3. If PMSS permits threaded construction, piping buried underpaving shall be welded construction.

7.12 Offsite Interconnecting Piping

7. 12 .1 General

1. Offsite facility interconnecting lines (i.e., tank farm,utility facilities, loading/unloading docks, or racks) andlines between process units and offsite shall be checkedfor hydraulic transient (surge or water hammer). If thereis potential for hydraulic surge or water hammer, hydraulictransient analysis shall be performed and submitted toPurchaser for approval.

2. Slow-closing valves shall be used to control hydraulicsurge or water hammer. If hydraulic transients cannot becontrolled within reasonable valve closure times, two speedvalve operators may be used. Other surge reduction devices,such as air chambers, hydraulic accumulators, and bypasslines, may be used if approved by Purchaser.

3. Air shall be eliminated from lines through use of eccentricreducers, air eliminators, vents, etc.

4. Motor operators may be considered for all large valves thatwill be operated frequently. Motor operators shall notnormally be required on maintenance or isolation valves.Valves that are remotely operated shall have motor



operators.

5. Unless approved otherwise, interconnecting process linesshall not be run underground.

7. 12 .2 Cooling Water Piping

1. Piping with circulating water rate of 10,000 gpm or moreshall be analyzed for transient conditions caused by valveclosure, pump start, or unexpected pump shut-off (powerfailure). Analysis of hydraulic transients shall besubmitted to Purchaser for approval.

2. Cooling water circulating pump discharge piping immediatelydownstream of check valve and block valve may be locatedunderground to facilitate anchoring the line.

3. Pump discharge lines with NPS 16 or larger check valveshall be analyzed for water hammer caused by closure ofcheck valve.

7. 12 .3 Cooling Tower Return Water Piping

1. Cooling towers circulating cooling water in hydrocarbonservice shall have open vents.

2. Vents shall be located at top of each cooling water returnriser at tower to permit escape of any gases leaking intosystem.

3. Cross-sectional area of vents shall be sized to handlemaximum volume of gas resulting from an exchanger tuberupture as determined by tube rupture analysis inaccordance with GEMS K-3D.

4. Vents shall release this calculated volume of gas withoutoverpressuring cooling tower water distribution headers.

5. Height of each vent stack shall be determined by coolingtower Supplier in accordance with GEMS U-1M.

6. Vents shall not normally be required on return risers forcooling towers serving steam service condensers, or similarsystems, where escape of gases is considered remote.

7.13 Tankage Piping

7. 13 .1 Provisions for Tank Settlement

1. Tank piping shall be designed to withstand a predeterminedamount of tank settlement after initial tank hydrotest.

2. Tank settlement shall preferably be accommodated usingpiping arrangement and/or flexible supports.

3. Flexible connections in hydrocarbon service shall not beused. If flexible pipe joints are used for other services,Purchaser approval shall be required. Two Dresser CouplingStyle 38 connections spaced a minimum of 10 feet apartshall be provided. Standard Dresser harnesses shall be usedto prevent pipe from slipping out of coupling.

7. 13 .2 Piping Penetrating Tank Farm Dikes

1. Piping shall preferably be routed to avoid penetrating dikewalls.

2. Unsleeved pipes that penetrate tank farm dikes shall havepipe to dike anchor/seal.



3. Insulated pipe shall be sleeved per Section 7.11.3.

7. 13 .3 Block Valves (For Flammable Liquid Storage Tanks)

1. Except where chemical characteristics of liquid stored areincompatible with steel, steel block valves shall be usedfor each connection to an aboveground storage tank throughwhich liquid can normally flow.

2. Block valves shall be bolted directly to flanged tanknozzles.

3. Support for large block valves at tank nozzles shall beconsidered to prevent overstressing tank shell.

7. 13 .4 LPG Vessels

1. Fittings and piping on spheres and horizontal vessels shallconform to Drawings 3S-2468, 3S-2470, 3S-2471, and 3S-2472.

2. Fittings and piping shall also conform to Texaco’s“Liquefied Petroleum Gas (LPG) Storage and HandlingGuidelines”.

7.14 Truck and Tank Car Loading Facilities

Facilities that contain normal butane and lower atmospheric boilingpoint hydrocarbons shall have an excess flow valve upstream of loadingline block valve to provide hose break protection and a check valve onstorage tank in vapor return line.

7.15 Fluid Catalytic Cracking Units (FCCU)

7. 15 .1 Check System

1. To check movement of large lines and expansion or rotationof joints, a system of reference points shall be set up.

2. System shall be shown on a drawing. Theoretical designmovements to reference points and maximum allowablemovements of joints shall also be shown on drawing.

3. Measurements shall be taken before initial start-up.

7. 15 .2 Valve Taps

1. Slide valves that are normally operated during an operatingperiod shall have an NPS 1 tapped connection in stuffingbox wall opposite lantern gland for introducing emergencyplastic packing. Tapped connection shall have an NPS 1schedule 160 nipple and block valve.

2. Gate valves in catalyst lines and other services linesconnected to catalyst lines shall have bossed and tappedconnections per Drawing 9S-7651. Connections shall havepermanent piping for aeration or purge. Piping shall beshown on process and instrument flow diagrams.

7.16 Acid and Caustic Lines

7. 16 .1 Location

1. Except if working area, passage, or access to equipmentwould be obstructed, acid and caustic lines shall belocated aboveground on low supports. Acid or caustic linesshall not be located below grade without Purchaserapproval.

2. Where use of low supports is not practical on processunits, acid and caustic lines shall be located on overhead



supports.

3. Acid lines at road crossings and similar obstructions shallbe located on overhead supports.

4. Acid lines crossing earth dikes or levees shall be locatedon low aboveground supports.

5. If suction or other flow conditions make location of acidlines on aboveground or overhead supports impractical, thelines shall be installed in concrete trenches.

6. Acid and caustic piping shall be arranged to avoid closeproximity to hot process piping.

7. 16 .2 Construction

1. Use of flanged joints and valves shall be minimized.

2. Flanged joints and valves shall not be located in overheadroad crossings or passageways where leaks could injurepassing personnel.

3. Non-indicating type tie-on covers shall be provided atvalves, flanges, and other points of potential leakage,similar to Ramco “Spra-Gard” or equal.

7. 16 .3 Insulation and Winter Protection

1. Insulation shall be used as necessary to prevent gain orloss of heat.

2. Heat tracing and insulating shall be performed inaccordance with GEMS G-1D.

8. PIPING EXPANSION, FLEXIBILITY, AND SUPPORT

8.1 Thermal Expansion of Piping

8. 1 .1 General

1. Anchors, stops, and/or guides shall be provided to directthermal expansion away from pumps, turbines, and otherequipment.

2. Effects of solar radiation on exposed field lines shall beconsidered.

3. If required by analysis, lines handling flammable fluidsand hot process water shall have expansion pipe loops. Ifapproved by Purchaser, expansion joints may be used:

a. In special cases where high viscosity liquids and closehookups make loops impractical.

b. In FCCU feed risers, standpipes, spent catalyst riserand reactor and regenerator overhead lines, i.e., largecatalyst bearing lines normally used during operation.

4. If required, expansion pipe loops shall be used for mainsteam lines and headers.

5. Hot lines crossing unit limits shall have anchors insideand near unit limits.

a. Anchors shall be designed to handle forces and momentsof lines inside and outside of unit limits.

b. Forces and moments resulting from expansion of lines



outside of unit limits will be supplied by Purchaser onrequest.

6. Piping to pumps and turbines shall conform to Section7.7.4.

8. 1 .2 Thermal Expansion During Steam-out

1. Thermal expansion during steam-out of hydrocarbon piping onprocess units shall be designed on the basis of 300°F at 50psig, regardless of pressure-temperature conditions ofsteam used for steam-out.

2. Thermal expansion effects due to these design conditionsshall be applied only if they exceed thermal expansioneffects resulting from process design operating conditions.

3. Offsite field lines, dock lines, etc., shall be designedfor thermal expansion during steam-out only if such linesrequire either:

a. Purging with steam due to liquid handled and procedureof operation.

b. Steam-out maintenance.

8.2 Pipe Supports and Anchors

8. 2 .1 General

1. Supports, guides, and anchors for all piping shall beengineered and shown on project drawings.

2. NPS 3 and smaller lines with excessive distance betweensupports or guides may be supported from an adjacent largeline, if larger line meets the following:

a. Line is uninsulated and operating at a temperature of160°F or less.

b. Attachment to postweld heat treated and stainless steelline shall be by a method other than welding.

3. Top of concrete supports shall have a steel plate orstructural shape to act as a sliding surface for all lines.

4. Lines that will be hydrostatically tested for initialconstruction in accordance with GEMS J-1P shall bepermanently supported to sustain such loads during initialconstruction and at subsequent turn-around periods. Linesthat must be flushed with liquid shall also be supported tosustain such loads.

5. Vertical deflection of pipe between supports shall belimited to 1 inch.

6. Line supports that are likely to require adjustment afterinstallation (to compensate for thermal expansion orsettlement) shall have an adjustable support.

7. If slab settlement will occur, supports for low lines neargrade shall be jack screw adjustable type.

8. Supports for cold service insulated lines shall permitcontinuous insulation of lines at support beam. Supportsshall conform to GEMS I-3M.

9. Pipe anchors shall be designed for maximum forces developedunder the most severe conditions per Section 8.3.1.



10. Piping restraints to limit forces and moments on rotatingequipment shall be designed to minimize deflection underload.

11. Supports shall be such that vertical expansion of pipe willnot render supports ineffective.

12. Underground pressure bell and spigot type piping shall besecured with anchors to prevent separation of joints due tounbalanced thrusts.

8. 2 .2 Pipe Racks

1. Space on pipe racks for future lines shall conform to GEMSG-2D.

2. Cross plant overhead pipe racks (outside process units)shall be designed such that columns and foundations cansupport a future upper deck of lines with a uniformlydistributed piping load equal to 50% of the piping loadcarried on the most heavily loaded deck. Single columnsupports for one or two lines and racks from cross plantracks terminating at a process unit shall not be requiredto sustain such a load.

3. Lines located close to grade on sleepers shall have minimumclearance of 12 inches from grade to a bare line or toinsulation on steam traced and insulated lines.

4. Requirements for future space on offsite piping supportsshall be ascertained on a project by project basis.

8. 2 .3 Support Shoes

1. Insulated lines NPS 3 and larger shall have support shoes.

2. Insulated lines NPS 2 and smaller can rest on insulationjacket.

3. Lines with pipe shoes shall be designed such that pipingand piping supports adequately provide for abnormal linemovements caused by upset or emergency conditions. Thisdesign check is to eliminate possibility of pipe shoesmoving completely off structural pipe supporting members.

4. Shoes shall be designed to permit installation and sealingof insulation.

5. Pipe shoes shall have vertical 1 inch wide slots forbanding insulation jackets. Slots shall be spaced to allowbands on approximately 18 inch centers on thermalinsulation and 12 inch centers on cold insulation.

8. 2 .4 Pipe Hangers

1. If suspended type supports are necessary, either with orwithout springs, rod type shall be preferred.

2. If spring type supports are used, a tabular list shall beprepared to record calculated required movement, maximumspring travel, and cold installation measurements. Uponconclusion of project, list shall be given to Purchaser.

8. 2 .5 Auxiliary Supports

1. In addition to supports required during operation and forhydrostatic test, auxiliary supports shall be provided toadequately support piping while disconnected from the



following:

a. Exchanger channel nozzles.

b. Flanged connections at safety relief valves, if attachedpiping weighs more than 50 pounds.

c. Pumps, compressors, and drivers.

d. Locations that require removable piping spools.

e. Vessel steam-out swing ells.

2. If cribbing of the line from grade is easily achieved,supports in paragraph 1. need not be permanent.

3. Supports for high lines to exchanger channel nozzles may bebolted attachments welded to exchanger shell flange orsaddle supports. Support attachments shall not be made toexchanger shell.

4. Passageways or working space for removing flange boltingshall not be obstructed by supports.

8. 2 .6 Support Attachments to Alloy and Stress Relieved Lines

1. Attachments on lines requiring stress relief shallpreferably be welded and stress relieved in shop.

2. To minimize use of stress relieved welded attachments,shoes and hangers may be attached to alloy and stressrelieved carbon steel lines with bolted clamps.

8. 2 .7 Galvanized Pipe Supports

1. Steel pipe support elements shall be galvanized inaccordance with GEMS S-1M if either “Light StructuralFraming” or “All Structural Steel” is specified to begalvanized.

2. Galvanized steel pipe support members shall not be incontact with austenitic stainless steel piping.

3. Welding of pipe support assemblies to be galvanized shallbe done with continuous welds.

8. 2 .8 Friction Effects

1. Anchor design in piping systems shall include effect offrictional resistance to thermal movement of pipe.

2. A coefficient of friction of 0.3 shall be assumed for steelto steel contact and 0.1 for polytetrafluoroethylene (PTFE)to steel contact.

3. Frictionless unrestrained movement of piping system shallbe assumed only if entire system is supported by rods orspring hangers.

8. 2 .9 Slide Pads

PTFE slide pads shall be designed in accordance with thefollowing:

1. Upper slide surface shall be stainless steel with a smoothfinish that completely covers PTFE at all times toeliminate possibility of cold flow, ridging, or damage toPTFE surface.

2. Lower slide pad shall consist of a PTFE pad bonded to acarbon steel plate.



3. Stainless steel plate and PTFE surfaces shall not bepainted and shall be free of weld splatter.

8.3 Piping Flexibility Analysis

8. 3 .1 General

1. Practices outlined in this section are minimum requirementsfor piping flexibility analysis.

2. Flexibility analysis for piping shall conform to ASMEB31.3.

3. Temperature Conditions

a. Analysis shall consider most severe operatingtemperature sustained during start-up, normal operation,steam and/or decoking, shutdown, or regeneration.

b. Analysis shall be for maximum temperature differential.

c. Climatic effects shall be considered in determiningmaximum differential temperature.

d. Installation temperature shall be assumed to have been70°F.

e. Metal temperature from effect of solar radiation shallbe assumed to be 150°F in summer and winter dry designbulb temperature in winter.

4. Vessels

a. Vessels that may have residual vapors or liquids,creating a hazard for maintenance personnel, shall beconsidered subject to steam purge, unless linings orcatalyst dictate other methods of purging.

b. Design shall be based on the premise that, during start-up, vessels and piping are steam purged together.

c. Design shall be based on the premise that, duringroutine maintenance, all piping is blinded at vesselnozzles.

d. Flexibility analysis shall consider all possibletemperature combinations for vessel and attached piping.

e. Lines shall be designed with sufficient flexibility toaccommodate thermal displacement of vessel.

5. Pressure-temperature design conditions during steam-outshall be in accordance with Section 3.4.

6. Unless approved otherwise, use of cold spring for pipingsystems that connect to rotating equipment (compressors,turbine pumps) shall not be allowed.

8. 3 .2 External Load Limits on Equipment

1. Vertical In-Line Pumps

a. Small vertical in-line pumps (20 horsepower or less)immediately adjacent to suction and discharge flangesshall be supported by conventional pipe supports. Indetermining piping forces, pump shall be considered as arigid, but unanchored, segment of piping system.

b. Larger vertical pumps furnished with casing footmountsshall be supported on suitable foundations. Maximum



allowable forces and moments that may be applied tonozzles shall be limited to a combined stress equal toor lower than that permitted in ASME B31.3.

2. Centrifugal Pumps

a. Single stage, centerline mounted, two point support:

Allowable forces and moments published in API Standard610 shall be taken as a minimum, where applicable.

b. Multistage, centerline mounted, or barrel typehorizontal cases with four point supports:

Criteria shall be allowable forces permitted bymanufacturer.

c. Piping force and moment limitations may be increased by50% for reactions that occur only if a pump is notoperating (e.g., an idle pump [installed spare] or acondition during equipment steam-out).

d. If computations indicate that combined piping momentlimitations would be exceeded, a more rigid base plateand support assembly for horizontal pumps shall beevaluated as an alternative to revised piping layout.

e. To eliminate differential settlement between pumps andsupport for large, horizontal centrifugal pumpssupported at side or end suction nozzles, considerationshall be given to extending pump foundations.

3. General Purpose Steam Turbines

Maximum allowable forces and moments applied to turbineflanges by steam piping shall be limited to lesser valueallowed by NEMA Publication SM 23, Part 8 (Steam PipingSystems), or manufacturer's limitations.

4. Special Purpose Steam Turbines

a. Maximum allowable forces and moments applied to turbineflanges by steam piping shall be limited to values thatare acceptable to both Purchaser and manufacturer butnot larger than one-half of NEMA SM 23 value.

b. Packless expansion joint shall be used to connectturbine exhaust and surface condenser. If start-up andoperating temperatures permit, an elastomer joint shallbe preferred to isolate turbine vibration and dampennoise.

5. Centrifugal Compressors

a. Maximum allowable forces and moments applied tocentrifugal compressors shall be limited by compressordesign.

b. Compressors shall be designed to withstand externalforces and moments at least equal to values calculatedper NEMA SM23, Part 8.

6. Exchangers (Air-Cooled)

Maximum allowable forces and moments applied to air coolerflanges shall be limited to values acceptable to bothPurchaser and manufacturer.



7. Exchangers (Shell and Tube)

Allowable forces from thermal displacements of piping andequipment shall be limited to allowable stresses specifiedin ASME Boiler and Pressure Vessel Code, Section VIII, Div.2.

8. Fired Heaters and Steam Generators

a. Allowable forces and moments on heater nozzles shall bemutually agreed upon by Purchaser and manufacturer andshall conform to applicable codes and specifications.

b. Displacement of heater tubes shall be approved by heatermanufacturer. Effect of expansion and/or displacement oftubes shall be reflected in computer analysis of pipingsystem.

c. Heaters designed with a floating coil (all spring orcounterweight mounted) shall have fail-safe limit stopsin all directions.

d. Computer analysis of piping systems connected tofloating heater coils shall include heater coil or anapproximate model of coil as part of systems and effectsof internal guides and restraints.

e. If heater coils are floating, support of connectingpiping systems shall be completely and independentlybalanced such that no dead load is imposed on coil.

9. Pressure Vessels and Miscellaneous

Allowable stresses from thermal displacements of piping andequipment shall be limited per ASME Boiler and PressureVessel Code, Section VIII, Division 2.

8. 3 .3 Analysis

1. Piping stress analysis shall be performed on the followingsystems:

a. Process, regeneration, and decoking lines to and fromfired heaters and steam generators.

b. Process lines to and from centrifugal compressors andblowers.

c. Steam lines to and from turbines.

d. Lines with design temperatures over 800°F.e. NPS 16 and larger lines.

f. NPS 3 and larger lines at design temperature of lessthan -20°F. NPS 6 and larger lines at designtemperatures over 200°F.

g. Pump lines NPS 3 and larger.

h. NPS 4 and larger lines to air coolers.

i. Lines to and from reciprocating pumps and compressors.

j. Lines to vessels that cannot be disconnected forpurging, steam-out, etc.

k. NPS 3 and larger lines subject to significantdifferential settlement of tanks, vessels, equipment, orsupports.



l. Relief systems, whether closed or relieving toatmosphere, with considerations for attached or detachedtail pipes. Analysis shall also include the following:

(1) Discharge reaction force caused by relief.

(2) Piping flexibility for thermal expansion during anyhot relief or contraction during cold relief.

(3) If possibility exists, dynamic loads from worstpossible flow conditions, including liquid massesaccelerated to sonic or subsonic velocities byexpanding gases.

m. Lines subject to mixed phase flow (liquid and vapor).

n. Lines subject to external pressure (by vacuum orjacketing).

o. Nonmetallic process lines.

2. Computer analysis shall be performed on all piping systemsdescribed in paragraph 1.a. to 1.d. Based on judgment ofpipe stress analyst, computer analysis in other pipingsystems (paragraphs 1.e. to 1.o.) shall be optional.

3. A vibrational (hydraulic and acoustically induced) analysisshall be performed on lines to and from reciprocatingcompressors (see Section 7.4.3).

4. Hydraulic transient analysis on offsite lines shall conformto Section 7.12.1.

5. Large diameter thin wall lines shall be analyzed forcrushing loads at support points. Lines shall be reinforcedas necessary.

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