normas texaco gems k-7d7 liquid level measurement

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DEC 96 LIQUID LEVEL MEASUREMENT GEMS K-7D7 PAGE 1 OF 27 ©TEXACO GENERAL ENGINEERING DEPARTMENT TABLE OF CONTENTS PAGE 1. SCOPE .............................................................. 4 2. REFERENCES ......................................................... 4 2.1 Purchaser Specifications ..................................... 4 2.2 Purchaser Drawings ........................................... 4 2.3 Industry Codes and Standards ................................. 5 3. DESIGN PHILOSOPHY .................................................. 5 3.1 General ...................................................... 5 3.2 Instrument Air Supply ........................................ 6 3.3 Winterproofing ............................................... 6 3.4 Electrical Requirements ...................................... 6 3.5 Transmitters ................................................. 6 3.6 Panel Mounted Level Instruments .............................. 6 3.7 Pneumatic Level Instruments .................................. 6 4. RANGES AND RESIDENCE TIMES ......................................... 6 4.1 General ...................................................... 6 4.2 Definitions .................................................. 7 4.3 Level Controllers ............................................ 7 4.4 Level Shutdown Devices (LS) .................................. 8 5. DIFFERENTIAL PRESSURE TYPE ......................................... 8 5.1 Application .................................................. 8 5.2 Materials and Construction ................................... 9 5.3 Installation ................................................. 9 5.4 Safety ....................................................... 9 6. DISPLACEMENT TYPE .................................................. 10 6.1 Application .................................................. 10 6.2 Design ....................................................... 10 6.3 Materials and Construction ................................... 10 6.4 Installation ................................................. 11 7. BALL FLOAT TYPE .................................................... 12 7.1 Application .................................................. 12 7.2 Design ....................................................... 12 7.3 Materials and Construction ................................... 12 7.4 Installation ................................................. 13 7.5 Safety ....................................................... 13 8. NUCLEAR LEVEL SYSTEMS .............................................. 13 8.1 Application .................................................. 13 8.2 Design ....................................................... 13 8.3 Materials and Construction ................................... 13

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Page 1: Normas Texaco GEMS K-7D7 Liquid Level Measurement

DEC 96 LIQUID LEVEL MEASUREMENT GEMS K-7D7

PAGE 1 OF 27©TEXACO GENERAL ENGINEERING DEPARTMENT

TABLE OF CONTENTSPAGE

1. SCOPE .............................................................. 4

2. REFERENCES......................................................... 4

2.1 Purchaser Specifications ..................................... 42.2 Purchaser Drawings ........................................... 42.3 Industry Codes and Standards ................................. 5

3. DESIGN PHILOSOPHY .................................................. 5

3.1 General ...................................................... 53.2 Instrument Air Supply ........................................ 63.3 Winterproofing ............................................... 63.4 Electrical Requirements ...................................... 63.5 Transmitters ................................................. 63.6 Panel Mounted Level Instruments .............................. 63.7 Pneumatic Level Instruments .................................. 6

4. RANGES AND RESIDENCE TIMES ......................................... 6

4.1 General ...................................................... 64.2 Definitions .................................................. 74.3 Level Controllers ............................................ 74.4 Level Shutdown Devices (LS) .................................. 8

5. DIFFERENTIAL PRESSURE TYPE ......................................... 8

5.1 Application .................................................. 85.2 Materials and Construction ................................... 95.3 Installation ................................................. 95.4 Safety ....................................................... 9

6. DISPLACEMENT TYPE .................................................. 10

6.1 Application .................................................. 106.2 Design ....................................................... 106.3 Materials and Construction ................................... 106.4 Installation ................................................. 11

7. BALL FLOAT TYPE .................................................... 12

7.1 Application .................................................. 127.2 Design ....................................................... 127.3 Materials and Construction ................................... 127.4 Installation ................................................. 137.5 Safety ....................................................... 13

8. NUCLEAR LEVEL SYSTEMS.............................................. 13

8.1 Application .................................................. 138.2 Design ....................................................... 138.3 Materials and Construction ................................... 13

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8.4 Installation ................................................. 138.5 Safety ....................................................... 13

9. ULTRASONIC CONTINUOUS LEVEL MEASUREMENT (NON-CONTACT).............. 13

9.1 Application .................................................. 139.2 Design ....................................................... 149.3 Materials and Construction ................................... 149.4 Installation ................................................. 14

10. ULTRASONIC POINT LEVEL MEASUREMENT (CONTACT) ....................... 14

10.1 Application .................................................. 1410.2 Materials and Construction ................................... 1510.3 Installation ................................................. 15

11. CAPACITANCE CONTINUOUS LEVEL MEASUREMENT........................... 15

11.1 Application .................................................. 1511.2 Design ....................................................... 1511.3 Materials and Construction ................................... 15

12. SPECIAL TYPES ...................................................... 16

13. GAGE GLASSES....................................................... 16

13.1 Application .................................................. 1613.2 Design ....................................................... 1713.3 Materials and Construction ................................... 1813.4 Installation ................................................. 18

14. TUBULAR GAGE GLASSES............................................... 19

14.1 Application .................................................. 1914.2 Design ....................................................... 1914.3 Materials and Construction ................................... 1914.4 Installation ................................................. 19

15. HYDROSTATIC TANK GAGING ............................................ 19

15.1 Application .................................................. 1915.2 Design ....................................................... 2015.3 Materials and Construction ................................... 2115.4 Installation ................................................. 2115.5 Safety ....................................................... 21

16. RADAR TANK GAGING (RTG) ............................................ 21

16.1 Application .................................................. 2116.2 Design ....................................................... 2216.3 Installation Requirements - Parabolic Antenna Gage ........... 22

17. TAPE AND FLOAT TANK GAGING ......................................... 23

17.1 Application .................................................. 2317.2 Design ....................................................... 23

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17.3 Materials and Construction ................................... 2317.4 Installation ................................................. 2417.5 Safety ....................................................... 24

18. SERVO GAGES........................................................ 24

18.1 Application .................................................. 2418.2 Design ....................................................... 2518.3 Materials and Construction ................................... 2618.4 Installation ................................................. 2618.5 Safety ....................................................... 27

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DEC 96 LIQUID LEVEL MEASUREMENT GEMS K-7D7

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1. SCOPE

This specification defines minimum requirements for selection,materials, construction, and installation of gage glasses, gage columns,liquid level transmitting instruments, nuclear level systems, ultrasoniclevel transmitters, capacitance level transmitters, hydrostatic tankgaging, radar tank gaging, tape and float tank gaging, and servo gages.

2. REFERENCES

2.1 Purchaser Specifications

This specification contains references to the following Purchaserspecifications:

1. GEMSGC, “General Conditions - General Equipment and MaterialSpecifications”.

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

3. GEMS J-1D, “Piping - Design”.

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

5. GEMS K-1D, “Instruments and Control Equipment”.

6. GEMS K-6D, “Flow Measurement”.

7. GEMS K-8D, “Pressure Measurement”.

8. GEMS K-10D, “Field Mounted Pneumatic Controllers, Recorders, andIndicators”.

9. GEMS K-13D, “Signal Transmission”.

10. GEMS K-14D, “Control Room Instrumentation - DCS, Electronic, andPneumatic”.

11. GEMS K-17D, “Alarms, Shutdowns, Logic, and Sequential SystemsDesign”.

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

13. GEMS K-101M, “Electronic Transmitters - Material Purchase”.

14. GEMS K-102M, “Current to Pneumatic Transducers - MaterialPurchase”.

15. GEMS K-701M, “Gage Glasses and Cocks”.

16. GEMS K-703M, “Float Level Switches”.

17. GEMS K-704M, “Displacement Level Instruments”.

18. GEMS K-706M, “Nuclear Level Systems”.

19. GEMS K-707M, “Ultrasonic Level Transmitters”.

20. GEMS K-708M, “Ultrasonic Point Level Transmitters”.

21. GEMS K-709M, “Capacitance Level Transmitters”.

22. GEMS L-1P, “Installation of Electrical Systems”.

2.2 Purchaser Drawings

This specification contains references to the following Purchaserdrawings:

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DEC 96 LIQUID LEVEL MEASUREMENT GEMS K-7D7

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1. 6S-6290, “Common Platform and Gaging Arrangement for Floating RoofTanks”.

2. 6S-7238, “Gage Plate for Storage Tanks”.

3. 9S-7691, “Steam Tracer Arrangement for Instrument and PipingItems”.

4. 9S-8123, “Orientation of Gage Glasses and Case on DisplacementLevel Instruments”.

5. 9S-8125, “Gage Type Displacement Level Instrument - PipingDetails”.

6. 9S-8976, “Typical Tank Gage Installation”.

7. 9S-9166, “Requirements and Piping for Direct Connected GageGlasses”.

8. 9S-9167, “Gage Glass Pipe Columns”.

9. 9S-9170, “Differential Pressure Transmitter Alloy Tubing -Instrument Piping”.

10. 9S-9191, “Differential Pressure Transmitter C.S. Pipe - HorizontalOrifice Runs - Instrument Piping”.

2. 3 Industry Codes and Standards

This specification contains references to the following industry codesand standards:

2. 3 . 1 American Petroleum Institute (API)

RP500, “Recommended Practice for Classification of Locationsfor Electrical Installation of Petroleum Facilities”.

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

1. B16.5, “Pipe Flanges and Flanged Fittings”.

2. Boiler and Pressure Vessel Code, Section I, “PowerBoilers”.

2. 3 . 3 Institute of Electronics and Electrical Engineers (IEEE)

344, “Seismic Qualifications of Class 1E Equipment for NuclearPower Generating Stations”.

2. 3 . 4 National Fire Protection Association (NFPA)

70, “National Electrical Code (NEC)”.

3. DESIG N PHILOSOPHY

3.1 General

1. Level indication, recording, and control typically shall beperformed in a distributed control system (DCS).

2. Differential pressure level transmitters shall be preferred forprocess measurement with a span of 12 inches or greater.

3. Connections to level gages and external type level instrumentsshall be self-draining into the vessel on which they are installed.

4. Level instruments shall span anticipated maximum liquid range.

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PAGE 6 OF 27©TEXACO GENERAL ENGINEERING DEPARTMENT

5. If both level transmitter and gage glass are specified, gage glasstaps shall be located such that gage glass indication includes spanof transmitter flanges.

6. Except on compressor suction vessels, connections into vesselbottoms shall include the following to detect or control liquidbuildup in a normally dry vessel:

a. Sediment pocket that conforms to details on Drawing 9S-9166.

b. Internal riser in vessel.

7. Compressor suction vessels shall have a boot to detect liquidentry. Point of take-off shall be from the side of the boot to makeinstrument self draining and prevent plugging of lower connection.

8. Level instruments used for shutdown initiation shall conform toGEMS K-17D.

3.2 Instrument Air Supply

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

3.3 Winterproofing

Winterproofing shall conform to GEMS G-1D.

3.4 Electrical Requirements

Electrical installation and classification of instruments shall conformto GEMS K-1D.

3.5 Transmitters

Transmitters shall conform to GEMS K-1D, K-101M, and K-102M.

3.6 Panel Mounted Level Instruments

Panel mounted level instruments shall conform to GEMS K-14D.

3.7 Pneumatic Level Instruments

Pneumatic level instrumentation shall conform to GEMS K-10D. (Levelindication, recording, and control shall normally be performed in adistributed control system [DCS].)

4. RANGES AND RESIDENCE TIMES

4.1 General

1. Final selection of ranges shall be subject to Purchaser approval.

2. The range for the following services shall approximately span theentire height or diameter of the vessel on which it is to be used:

a. Charge drums.

b. Surge drums.

c. Reflux accumulators.

d. Gas separators.

e. Compressor and suction drums.

f. Steam condensate drums.

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4.2 Definitions

1. Liquid residence time: time in minutes between LLL and HLL atnormal operating rate into or out of vessels.

2. The following abbreviations are used in this used (instrument tagprefixes may vary slightly, depending on site standards forinstrument numbering):

a. LAXH: high level shutdown. This is the highest position thatliquid can reach without shutting down equipment dependent onthe vessel. (Dependent equipment could be an offgascompressor.) This position usually determines the elevationfor an LX nozzle.

b. LAHH: pre-trip level alarm high for a shutdown device.

c. HLL: high liquid level. This is the highest position thatliquid can be held for either continuous or intermittentperiods without impairing intended process function of vessel.(A process function could be to disengage liquid droplets fromoutlet vapor.) This position usually determines the elevationfor an LT nozzle.

d. LX: level shutdown device.

e. LAH: level alarm high.

f. LG: level gage or glass.

g. LC: level controller.

h. LT: level transmitter. Range of an LC or LT is usually fromLLL to HLL.

i. NLL: normal liquid level.

j. LAL: level alarm low.

k. LLL: low liquid level. This is the lowest position that liquidcan be held for either continuous or intermittent periodswithout impairing intended process function of vessel. (Aprocess function could be to provide minimum NPSH to a pumpand/or provide outlet liquid through a vortex breaker.) Thisposition usually determines the elevation for a LT nozzle.

l. LALL: pre-trip level alarm low for a shutdown device.

m. LAXL: low level shutdown. This is the lowest position thatliquid can drop without shutting down equipment dependent onthe vessel. (Dependent equipment could be a high pressureseparator outlet level control valve.) This position usuallydetermines the elevation for an LX nozzle.

n. VB: vortex breaker.

4.3 Level Controllers

1. Level controller range shall span LLL to HLL.

2. The range for level control instruments on fractionator towers andstripper towers shall be based on the following:

a. If the stream leaves the unit and does not flow directly toanother operating unit or stream flows to storage, sewers, ordrains, a minimum residence time of 2 minutes LLL to HLL shallbe provided in sizing level instruments.

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b. If the bottom of one tower is the charge to another tower, aminimum residence time of 5 minutes LLL to HLL shall beprovided for level instruments.

c. If the bottom of a tower is the charge to a fired heater, aminimum residence time of 15 minutes LLL to HLL shall beprovided for level instruments. If tower bottoms transfer to apumparound fired reboiler, reboiler outlet liquid shall not beincluded in residence time calculation.

d. LAH shall be set at 0.5 to 1.0 minute below HLL.

e. LAL shall be set at 0.5 to 1.0 minute above LLL.

f. VB top inlet shall be a minimum of 6 inches above bottom ofhorizontal vessels.

3. A minimum of 1 minute LLL to HLL shall be allowed for residencetime in condensate pots for steam boilers.

4.4 Level Shutdown Devices (LS)

1. LX high range shall span from LLL or below NLL to above LAXH.

2. LX low range shall span below LAXL to HLL or above NLL.

3. LX high-low range shall span from below LAXL to above LAXH.

4. LAHH shall be set at 0.5 to 1.0 minute below LAXH.

5. LALL shall be set at 0.5 to 1.0 minute above LAXL.

5. DIFFERENTIAL PRESSURE TYPE

5.1 Application

5. 1 .1 General

Differential pressure type transmitters shall be used for thefollowing:

1. Liquid level measurements greater than 12 inches forclean, non-viscous materials that do not require flushing.

2. Coking, slurry, or high viscosity service.

a. Transmitters used in certain coking or slurryservices shall be purged with a suitable liquid andshall have proper restrictions and piping arrangement.

b. Use shall conform to Drawings 9S-9170 and 9S-9191.

3. Bubbler type level systems may be used for levelmeasurement in applications, such as the following:

a. Plant waste water reservoirs.

b. Biological sludge storage tanks.

c. Sulfur pits.

d. Cooling tower basins or wells.

e. Extremely viscous materials.

f. Sludge like materials.

4. High temperature services, such as boiler drums.

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5. 1 .2 Remote Seals

1. Remote seals shall be used as follows:

a. Standard differential pressure transmitter wouldrequire flushing.

b. Highly corrosive materials are handled that wouldattack differential pressure transmitter internals.

c. High viscosity materials that require heat tomaintain liquid state are handled and one of thefollowing applies:

(1) No heat is available.

(2) Heat required to keep material in liquid statewould damage transmitter.

d. Batch operation with multiple products.

e. Within temperature limitation of seal fluid,typically 600 °F for silicone, 200 °F for glycol andglycerin.

2. Remote seals may be considered if freeze protection wouldhave to be applied to a standard differential pressuretransmitter.

5. 1 .3 Seal Pots

1. Seal pots shall be provided on the highest vesselconnection to a meter.

2. Pots shall be sealed with liquid from the vessel.

3. If steam condensate is present or liquid from the vesselis subject to freezing, sealing medium shall be glycol orglycerin.

5.2 Materials and Construction

1. Materials and construction requirements for differential pressureinstruments shall conform to GEMS K-8D and K-101M.

2. Materials and construction requirements for seal pots shall conformto GEMS K-8D and Drawing 95-9170.

5.3 Installation

1. Differential pressure transmitters shall be installed in accordancewith GEMS K-6D, GEMS K-8D, and Drawing 9S-9170.

2. Wiring, wiring materials, and wiring support shall conform to GEMSK-13D and L-1P.

5.4 Safety

1. Electrical requirements for transmitters shall conform to GEMS K-1D.

2. Accessibility requirements for instruments shall conform to GEMS J-1D.

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6. DISPLACEMENT TYPE

6.1 Application

1. Internal type displacement level instruments shall be used inliquids that boil at atmospheric temperatures or below (e.g.,ammonia) and it is essential that the displacer be maintained atvessel temperature.

2. External type displacement level measurements shall be used onvessel boots and condensate pots.

3. Displacement type level instruments shall not be used as follows:

a. If differential transmitter meets requirements.

b. For extremely viscous materials.

c. For any services that require purging to prevent thefollowing:

(1) Plugging and/or sticking.

(2) Excessive condensation or vaporization of fluids in thechamber due to vessel-chamber temperature differences.

d. If level measurement range exceeds 32 inches.

6.2 Design

1. Internal displacement level instruments shall have NPS - class 150ANSI minimum mounting flange.

2. If Supplier standard external type displacer body does not meetrequirements for access or maintenance, consideration shall begiven to using a top entry displacer mounted on a fabricatedchamber. Chamber shall be designed integrally with and extendthrough the vessel, with external connections and block valves attop and bottom of vessel. Upper section of chamber shall extendabove a platform located immediately above chamber connections toprovide access for adjustment of pilot and removal of head. Chamberextensions shall not exceed 4 feet.

3. Displacement type level instruments operating at temperatures above400 °F shall have transmitter heat protection (e.g., heatinsulator).

4. Pneumatic displacement type level instruments used as transmittersshall have transmitter type pilots and shall be subject toPurchaser approval.

6.3 Materials and Construction

6. 3 .1 General

1. Material and construction requirements for displacementtype level instruments shall conform to GEMS K-704M.

2. Displacement and float type level instrument chambers,housings, and internal parts shall have design ratingsadequate for applicable service conditions.

3. Displacers and internal trim shall normally be 316 SS.Extremely corrosive services shall require corrosionresistant materials.

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4. Torque or flexure tube material for displacer type levelinstruments shall be the material recommended bymanufacturer for applicable service conditions.

5. Except in services that require alloy material, displacerchambers, including head mounting flange, in hydrocarbonservice shall have class 300 minimum rating. If alloymaterial is required, chamber rating shall conform toapplicable piping material service specification (PMSS).Regardless of chamber rating, chamber process connectionnozzle rating shall conform to applicable PMSS.

6. Except for services in which chloride stress crackingcould occur with stainless steel, displacer chambers inhydrocarbon services with operating temperatures above450 °F shall be 316 SS. Alternate materials shall meet orexceed applicable service conditions and be subject toPurchaser approval.

7. Carbon steel displacer chambers shall normally be used inservices with temperatures below 450 °F.

8. If the vessel has a corrosion allowance greater than 1/8inch, metallurgy of the chambers shall provide at least asmuch corrosion protection as provided to the vessel. Suchcorrosion protection shall be subject to Owner approval.Extra strong carbon steel chambers shall be acceptable.

9. Other materials and construction items shall conform toDrawing 9S-8125.

6. 3 .2 Displacer Chamber Process Connections

1. Material for piping shall conform to requirements in PMSSunder level instrument material.

2. Top chamber process connections shall not be used. Eithertwo side connections or a side and bottom connection, toenable easy removal of instrument head for servicing,shall be used.

3. If a valved connection on the top chamber cover is notprovided, top chamber covers (head) shall be drilled andtapped for NPS 3/4 pipe connection.

4. Chamber head mounting flanges shall be NPS 4 - class 150minimum.

5. Chambers shall have a flanged joint with retained gasketabove upper connection to permit removal of displacer andinstrument head.

6.4 Installation

6. 4 .1 Piping Materials and Arrangement

1. Piping arrangement, clearances, and support required shallconform to Drawings 9S-8123 and 9S-8125.

2. Piping shall be arranged such that displacer can becalibrated if it isolated from vessel.

3. Chamber materials shall conform to applicable PMSS.

4. Vertical alignment of chamber shall be such that contactbetween displacer and chamber wall is prevented.

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5. Shipping stops shall be removed prior to installation.

6. 4 .2 Accessibility

Accessibility shall conform to GEMS J-1D.

7. BALL FLOAT TYPE

7.1 Application

1. Ball float type level instruments shall be used only if thefollowing two conditions apply:

a. Level transmitters do not span required range.

b. It is necessary to measure a point level for a single liquid.

2. Ball floats may alarm, lockout, or automatically shut downequipment by operating an electrical switch as the float moves overits range. Mercury switches shall be prohibited.

3. Use of ball floats for shutdown shall conform to GEMS K-17D.

4. Use of ball float instruments shall be subject to Owner approval.

7.2 Design

If in-service maintenance or testing is required, ball float type levelinstruments shall be external chamber mounted.

7.3 Materials and Construction

1. Ball float level instrument chambers, housings, and internal partsshall have design ratings that meet or exceed applicable serviceconditions.

2. Ball floats and internal trim shall normally be 316 SS. Extremelycorrosive services shall require corrosion resistant materials.

3. Torque or flexure tube material for ball float type levelinstruments shall be material recommended by manufacturer forapplicable service conditions.

4. Except in services that require alloy material, ball floatchambers, including float mounting flange, in hydrocarbon serviceshall have class 300 minimum rating. If alloy material is required,chamber rating shall conform to applicable PMSS. Regardless ofchamber rating, chamber process connection nozzle rating shallconform to PMSS.

5. Except for services in which chloride stress cracking could occurwith stainless steel, ball float chambers in hydrocarbon serviceswith operating temperatures above 450 °F shall be 316 SS. Alternatematerials shall meet or exceed applicable service conditions andshall be subject to Purchaser approval.

6. Carbon steel ball float chambers shall be used in temperaturesbelow 450 °F.

7. If the vessel has a corrosion allowance greater than 1/8 inch,metallurgy of ball float chambers shall provide at least as muchprotection as provided to the vessel. Such corrosion protectionshall be subject to Owner approval. Extra strong carbon steelchambers shall be acceptable.

8. Other materials and construction items shall conform to Drawing 9S-8125.

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7.4 Installation

Ball float type instruments shall be installed in accordance withrequirements for displacement type level instruments.

7.5 Safety

Accessibility shall conform to GEMS J-1D.

8. NUCLEAR LEVEL SYSTEMS

8.1 Application

1. Radioactive source type level transmitters may be used on thefollowing:

a. Viscous or dirty materials that cannot be measured by othermethods.

b. Liquids subject to polymer buildup.

c. Cryogenic service.

2. Use of radioactive source type level transmitters shall be subjectto Owner approval.

8.2 Design

1. Transmitters shall provide continuous level information (not highand low level detection only).

2. Radioactive source shall conform to appropriate Nuclear RegulatoryCommission (NRC) regulations or, if in an agreement state, meetthat state's regulations.

8.3 Materials and Construction

Materials and construction requirements for nuclear level systems shallconform to GEMS K-706M.

8.4 Installation

1. Nuclear level systems shall be installed in accordance with NRCregulations, local codes, and manufacturer's recommendations.

2. Source shall be mounted with shielding to prevent inadvertentexposure to radiation beam.

8.5 Safety

Electrical requirements for transmitters shall conform to GEMS K-1D.

9. ULTRASONIC CONTINUOUS LEVEL MEASUREMENT (NON-CONTACT)

9.1 Application

1. Within temperature and accuracy limitations stated by manufacturer,ultrasonic level transmitters may be used as follows:

a. For dirty services in which other types of measurement areineffective or less reliable.

b. If liquid coating or buildup caused by instrument contact withprocess liquid impairs other measurement devices (e.g.,floats).

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c. If variations in composition, density, thermal or electricalconductivity, capacitance, or other characteristics in fluidare common or expected.

d. Tank level measurement.

e. Sump level measurement.

f. Agitated liquids (surface waves).

g. Liquid or solids level measurement and controls, alarms, andpump controls.

2. Ultrasonic level transmitters shall not be used for the following:

a. Vacuum or pressure services above 50 psig because ofmeasurement inaccuracies at elevated pressures.

b. High density vapor space or with droplets forming a heavy fog.

c. High temperature vapor space.

d. Possibility of material buildup on sensor.

9.2 Design

1. Ultrasonic transmitters shall have integral temperature/velocitycompensation.

2. Ultrasonic transmitters mounted on vessels shall have NPS - class300 mounting flange.

9.3 Materials and Construction

Materials and construction requirements for ultrasonic level measurementshall conform to GEMS K-707M.

9.4 Installation

1. Methods of wiring, wiring materials, and support shall conform toGEMS K-13D and L-1P.

2. Sensors shall be located and mounted in accordance withmanufacturer's recommendations. Sound beam path shall not bephysically obstructed.

10. ULTRASONIC POINT LEVEL MEASUREMENT (CONTACT)

10.1 Application

1. Ultrasonic point level transmitters may be used as follows:

a. For general purpose point level measurement.

b. If foam, vapor, turbulence, or coating buildup impairs othermeasurement devices.

c. If variations in composition, density, thermal or electricalconductivity, capacitance, or other characteristics in fluidare common or expected.

2. Ultrasonic point level measurement shall be used for alarms, pumpcontrols, and valve controls.

3. Ultrasonic point level transmitters may alarm, lockout, orautomatically shut down equipment by operating an electrical switchas the level moves over its range.

4. Use of ultrasonic point level transmitters for shutdown shallconform to GEMS K-17D.

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5. Use of ultrasonic point level transmitters shall be subject toOwner approval.

10.2 Materials and Construction

Materials and construction requirements for ultrasonic point levelmeasurement shall conform to GEMS K-708M.

10.3 Installation

1. Methods of wiring, wiring materials, and support shall conform toGEMS K-13D and L-1P.

2. Sensors shall be mounted and oriented in accordance withmanufacturer's recommendations.

11. CAPACITANCE CONTINUOUS LEVEL MEASUREMENT

11.1 Application

1. Capacitance level transmitters shall be considered if any of thefollowing conditions exists:

a. High temperature and pressure prevent use of other leveldevices.

b. Measuring range cannot be measured by other means.

c. Physical installation of other devices is not practical orfeasible.

2. Capacitance level transmitters may be used for liquid levelmeasurement, alarms, and control.

3. Capacitance level transmitters may be used for level measurement inthe following:

a. Vessels.

b. Tanks.

c. Sumps.

d. Wells.

4. Capacitance level transmitters shall not be used for the followingconditions:

a. Media in which conductivity may change from nonconductive(less than 10 micro Siemens [ µS]) to conductive (greater than10 µS).

b. If on-line replacement of process wetted materials isrequired.

11.2 Design

1. Capacitance sensors shall have design ratings that meet or exceedapplicable service conditions.

2. Capacitance sensors shall be mountable vertically or horizontally.

3. Process connections shall be flanged in accordance with GEMS J-2Dand ASME B16.5.

11.3 Materials and Construction

Materials and construction shall conform to GEMS K-709M.

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12. SPECIAL TYPES

Other types of level instruments, such as resistance tape, RF, thermalconductivity, and vibrating reed, may be used for special applicationswith Owner approval.

13. GAGE GLASSES

13.1 Application

13. 1 .1 Gage Glass Pipe Columns

Gage glass pipe columns shall be provided for the following:

1. To span desired range if it is necessary to exceed themaximum allowable visible glass range (52 inches) of afour section assembly rather than provide multipleindividual assemblies with overlapping direct connectionsto vessel.

2. In fractionating tower level services above 250 °F, ifcondensation of vapor in upper connection is such thatliquid runs down gage glass quickly enough to create afalse level (e.g., depropanizers, debutanizers,depentanizers, and rich oil stills).

13. 1 .2 Transparent Armored Gage Glasses

Unless specified otherwise, gage glasses shall be armoredtransparent type.

13. 1 .3 Reflex Armored Gage Glasses

1. Use of reflex armored gage glasses shall be subject toPurchaser approval.

2. Reflex armored gage glasses may be used for the followingservices:

a. Extremely dirty services in which liquids tend toobscure glass.

b. Extremely light process services that meet thefollowing criteria:

(1) Service is clear and light.

(2) Service is not steam.

(3) Service is non-corrosive.

3. Reflex armored gage glasses shall not be used for thefollowing services:

a. Interface.

b. High viscosity.

c. Steam.

d. Condensate above 300 °F.

e. Services that coat glass or leave film.

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13. 1 .4 Local Level Indication

1. If approved by Purchaser, magnetic follower type orresistive type on-off level indication may be used.

2. Levels on boilers and steam services above 1500 psig areapplications that shall require alternate means for locallevel indication.

3. Selection of suitable local level indication in highlytoxic services shall be subject to Owner approval.

13.2 Design

1. Gage glasses shall be mounted on vessel nozzles separately fromother level instruments.

2. Gage glasses shall provide a visible indication of the vessel levelover the entire range of any level instrument on the vessel. Use ofa 12 inch gage glass with a 14 inch level instrument shall bepermitted on steam condensate pots.

3. Gage glasses may be required on vessels that do not use levelinstruments to provide a visible range of vessel level over thedesired distance.

4. Armored gage glasses shall be limited to two different pressureratings (unless service conditions involved exceed these ratings)and two different lengths of visible glass per single selection.

5. Maximum allowable visible glass ranges of one assembly shallconform to Drawing 9S-9166.

6. End connected type glasses shall be used if possible. Close hook-uptype gage glasses with side connections shall be avoided but may beused if space is severely limited.

7. Gage glasses and assemblies, including accessories (such as blockvalves, drain valves, and cocks), that fall under the jurisdictionof ASME Boiler and Pressure Vessel Code, Section I, shall conformto that code.

8. Gage glasses shall be suitable for cold hydrostatic test pressureof equipment on which they are to be used, as well as operatingconditions to which they will be subjected.

9. Gage glasses in services subject to frosting shall have a non-frosting extension that spans full visible range of gage glass.

10. If liquids are viscous and do not flow readily at normaltemperatures, gage glasses shall be heated by a method appropriateto applicable service conditions. Heating shall conform to GEMS G-1D and Drawing 9S-7691.

11. Gage glass housing connections shall be NPS 3/4 female.

12. If low boiling range materials might partially vaporize at thetemperature of the surrounding atmosphere, large chamber gageglasses may be used.

13. Light fixtures shall be provided on transparent gage glasses.

14. If available, power for illuminating gage glasses shall be takenfrom lighting distribution panels backed up by emergency powersupply, not from uninterruptable power. Gage glass illuminatorsshall not be powered from photocell-controlled circuits.

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15. Gage glass columns shall have multiple gage glass assembliesmounted on NPS 1-1/2 pipe in accordance with Drawing 9S-9167.

16. Gage glass columns on horizontal vessels greater than 32 inches indiameter designed with top and bottom connections shall use 2 inchnozzles and 2 inch standpipe.

13.3 Materials and Construction

1. General materials and construction requirements for gage glassesand gage cocks shall conform to GEMS K-701M.

2. Gage glass housings in hydrocarbon services up to 450 °F shallnormally be carbon steel. If the vessel involved has a corrosionallowance greater than 1/8 inch, metallurgy of housings shallprovide at least as much protection as provided to the vessel. Suchcorrosion protection shall be subject to Purchaser approval.

3. Except for services in which chloride stress cracking could occurwith stainless steel, gage glass housings in hydrocarbon serviceswith operating temperatures above 450 °F shall be 316 SS. Alternatematerials shall meet or exceed applicable service conditions andshall be subject to Purchaser approval.

4. Materials for parts, other than housing, shall conform tomanufacturer's recommendations.

5. Materials for gage glass columns, vents, and drain piping shallconform to materials shown on Drawings 9S-9166 and 9S-9167.

6. Gage cocks shall have removable seats, sleeves, and stems and shallbe made of corrosion resistant material if such condition isencountered.

7. Highly corrosive services shall require special material forcoating or lining (e.g., steam service, which requires micashielding or lining).

8. Spring washers (Bellville or equal) may be specified in steamservices and in services in which extreme temperature transientsare expected (spring washers provide live loading to bolts,packing, etc.). Instructions shall be followed for proper settingof Bellville washers.

13.4 Installation

1. Armored gage glasses and gage glass pipe columns shall be installedin accordance with details shown on Drawings 9S-9166 and 9S-9167and requirements in this section.

2. Bottom connections shall be arranged and located to be selfdraining to equipment as service permits per Drawing 9S-9167.

3. Orientation of gage glasses with respect to vessels and platformsshall conform to Drawing 9S-8123.

4. Block valves shall be provided at the top and bottom of each vesselor equipment connection for direct connected gage glasses and gageglass pipe columns. Block valves shall be NPS 1-1/2 minimum size.

5. To prevent excess leakage in the event of gage glass breakage, gagecocks with ball check valves shall be required for gage glasses(connected to a pipe column or direct connected) used on vesselscontaining materials, such as light hydrocarbons, which willvaporize at atmospheric pressure

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a. Suitable flush shall be used in levels services that can causesticking of ball check valve.

b. Valves shall have a method to equalize pressure across theball and allow an empty gage glass to fill from a full vessel.

c. Gage glass and gage cocks shall be removed as an assembly formaintenance.

14. TUBULAR GAGE GLASSES

14.1 Application

1. Tubular gage glasses shall be limited to off site services atatmospheric pressure and below 150 °F, where release of liquid (ifglass is broken) would not endanger personnel or equipment.Examples include:

a. Water.

b. High flash point oil

2. Tubular gage glasses shall not be used on process units.

3. Use of tubular gage glasses shall be subject to Owner approval.

14.2 Design

1. Tubular gage glasses shall have suitable gage cocks, top andbottom, and metal guards, such as rods, heavy wire, or other types,surrounding the glass tube.

2. Gage cocks for tubular glasses shall meet the followingrequirements:

a. Quick closing offset type to permit cleaning of glass inplace.

b. Material and rating of cock that meet or exceed applicableservice conditions.

c. Suitable packing gland for seating the 3/4 inch glass.

d. Drain and vent connections - NPS 1/2 female minimum.

e. Equipment connection - NPS 3/4 male union type.

f. Suitable guard support for glass.

14.3 Materials and Construction

1. Materials and construction shall conform to gage glassrequirements.

2. Type of glass, material, and gage cock shall meet or exceedapplicable service conditions.

14.4 Installation

Tubular gage glasses shall be installed in accordance with installationrequirements for gage glasses.

15. HYDROSTATIC TANK GAGING

15.1 Application

1. Hydrostatic tank gaging may be used for the following:

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a. Liquid level measurement in tanks or pressure vessels iferrors of +0.5 to 1.5 inches are acceptable.

b. Liquid level measurement for materials at temperatures between-40 °F and 180 °F. Supplier shall be consulted for highertemperature applications.

c. Mass inventory and on-line density calculation.

2. If significant material layering or stratification above the regionbetween upper and lower hydrostatic pressure sensors is expected,hydrostatic tank gaging shall not be used for liquid levelmeasurement. Stratification will introduce errors into the levelcalculations.

3. On-line density measurement is not available if liquid level isbelow upper hydrostatic pressure sensor.

15.2 Design

15. 2 .1 Pressure Sensors

1. Two hydrostatic head type pressure sensors shall be usedto measure liquid level in storage tanks and provide datato tank microprocessor, which shall compute liquiddensity.

2. A third pressure sensor, located at the top of the tank,shall be employed to measure tank pressure (gas blanketpressure) on non-atmospheric tank systems and compensatehydrostatic pressure sensors for pressure due to tank gasblanketing.

15. 2 .2 Resistance Temperature Detectors (RTDs)

1. RTDs shall be utilized to measure temperature of liquidcontents of tank.

2. RTDs shall be used to measure liquid product temperatureto calculate liquid product density with respect toreference density.

15. 2 .3 Data Processing

1. A microprocessor shall be provided to monitor inputs andcalculate mass of product stored.

2. Hydrostatic tank gaging systems shall have a means totransfer tank data to plant information system.

3. Portable terminals may be used for software, factors, andprogram changes in addition to local tank monitoring.

4. Tanks shall have a means for local level readout.

15. 2 .4 Typical Instrument Monitoring Output

1. Gross mass.

2. Net Mass.

3. Gross volume.

4. Net volume.

5. Available volume.

6. Level.

7. Time to fill.

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8. Density.

9. Reference density.

10. Temperature.

11. Alarms that may occur.

15. 2 .5 Typical Alarming Functions

1. High level.

2. High-high level.

3. Low level.

4. High and low tank temperature.

5. High and low sensor temperature.

6. Mass drift.

7. High and low reference density.

8. RTD uncovered.

9. Upper transmitter uncovered.

10. Tank empty.

11. Diagnostic alarm.

15.3 Materials and Construction

1. Pressure sensors shall have minimum ANSI class 150 RF flanges.

2. Studded flanges shall be used on atmospheric and light padded tanksto allow close coupling of sensor to tank.

3. Gasket material between pressure sensors and tanks shall begraphite type packing to reduce emissions and for fire safety.

15.4 Installation

1. Pressure sensors used to measure hydrostatic head shall beinstalled on minimum ANSI class 150 RF nozzles with studded flangesfor high pressure tanks.

a. Distance between sensors shall be recommended by Supplier.

b. Center line of bottom nozzle typically shall be located 6inches above invert elevation of tank floor.

c. Sensors shall be located away from suction and discharge totank nozzles and tank mixers to avoid differential effectscaused by turbulence.

2. Supplier shall be consulted for location of RTDs.

15.5 Safety

1. Electrical requirements for transmitters shall conform to GEMS K-1D.

2. Accessibility requirements for instruments shall conform to GEMS J-1D.

16. RADAR TANK GAGING (RTG)

16.1 Application

1. RTGs shall be used if high accuracy is required, typically +1 mm.

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2. RTGs shall be used if no contact with product is required.

3. RTGs may be used to measure levels of a wide range of liquids,slurries, and sludge.

16.2 Design

16. 2 .1 General

1. RTG mounting configuration may be any of the following:

a. Parabolic antenna.

b. Still pipe connection.

c. Liquid gas gage.

2. Parabolic antenna gages shall be used on fixed roof tankswith products ranging from clean products to harshenvironments and sticky products, such as asphalt.

3. Stilling wells shall be used in services that may haveboiling liquids or turbulence. If field verification ofRTG calibration is desired, calibration pegs may beinstalled in stilling well.

4. LPG/LNG gages shall be used for liquid gas.

16. 2 .2 Parabolic Antenna Gage

Parabolic antenna gages may be mounted on existing manholecovers.

16. 2 .3 Still Pipe Gage

Radar units shall be mounted on a stand that is mounted on thestill pipe flange.

16. 2 .4 Data Acquisition Unit (DAU)

1. If local readout of level is required, a data acquisitionunit (DAU) shall be connected to RTG.

2. Provisions shall be made for interface with a specifiedplant instrument control or information system.

3. DAUs shall be mounted at grade level.

16.3 Installation Requirements - Parabolic Antenna Gage

1. Manhole covers shall have the following characteristics:

a. Diameter shall be wide enough to allow reflector to sit easilyinside manhole cover.

b. Top of cover shall have a hole with a sufficient diameterthrough which antenna can be mounted.

2. If minimum distance from bottom of reflector to product surface is32 inches or less, accuracy of measurement shall be permanufacturer's specification.

3. Minimum distance from tank wall to antenna axis shall be permanufacturer's specification.

4. Parabolic antenna gages shall be mounted as follows:

a. Gage can be affixed to manhole cover with a welding neckflange that is welded to cover.

b. Welding neck flange shall as a minimum have class 150 rating.

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c. Gage shall be easily accessible for service.

17. TAPE AND FLOAT TANK GAGING

17.1 Application

1. Tape and float tanks gages shall be considered on storage tanks forwhich an accuracy of +1/8 inch is required and the followingconditions are met:

a. Design pressures do not exceed 300 psig.

b. Design temperature is less than 300 °F.

c. Measurement range does not exceed 100 feet

2. On floating roof tanks, tapes shall be:

a. Attached to a float in a gage well in the floating roof.

b. Protected to prevent measurement errors caused by wind.

17.2 Design

1. Entry point of automatic tank gages shall be located on a splitmanway for accessibility. If split manway location is unavailable,entry point shall be as close to a manway as possible.

2. Sufficient distance shall be maintained from mechanical agitationand suction and filling lines to minimize disturbances that couldinduce errors into level measurement.

3. Stilling wells shall be considered for applications in whichturbulence caused by high emptying and filling rates or mechanicalagitators can affect float. Boiling surface services, such asliquified petroleum gas (LPG), shall usually require a stillingwell.

4. Tank gaging transmitters are available for tape and float systems.Transmitter types to meet requirements of plant tank gaging systemshall be specified by Purchaser.

5. Point level detection can be provided by installation of camoperated switches on gage head.

6. Tanks with a nitrogen blanket shall have nitrogen piped throughtank gage pipe to provide a purged atmosphere for internalcomponents of tank gaging system.

7. Electronics section of gage shall be isolated from drum housing tomaintain a product free electronics section and to be waterproof.

8. Drum housing shall have internal barrier inherent by manufacture ofdevice to prevent flow of gaseous vapors into electronics section.

17.3 Materials and Construction

1. Tank gage head, pulleys, piping, floats, wire, and internal partsshall have design ratings that meet or exceed applicable serviceconditions.

2. Tank gaging system shall have a material of construction that iscompatible with service (e.g., aluminum gage head with 316 SSfloat).

3. Process connection shall meet applicable tank specification.

4. Flanged connections shall as a minimum have class 150 rating.

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5. Mounting hardware, brackets, etc., shall be made of suitablenoncorrosive material. Unless specifically approved otherwise,plated materials shall not be used.

6. Electronic transmitters shall have the following:

a. Power supply shall be specified by Purchaser to be 120 VAC 60Hz or 24 VDC. Electrical contacts, if required, shall be ratedat 120 VAC, 3 amp minimum resistive load.

b. Transmitter output shall be specified by Purchaser.

c. Transmitter shall have fully adjustable zero and span.

d. Radio frequency immunity (RFI) protection shall be as follows:

(1) 10 V/M field strength with frequencies from 20 to 500 MHz.

(2) Maximum variation of output signal from instrument undertest shall be 0.5% of span.

e. Minimum vibration limits of components shall be capable ofunaffected operation while subjected to an acceleration of 1 gat 40 Hz.

f. Integral filter shall be effective for approximately 40 dBattenuation at 4 Hz and higher frequencies.

g. Transmitters shall be approved for electrical areaclassification in which instrument will be installed.

7. Gages shall have stainless steel name tags, permanently attachedwith stainless steel screws and engraved with tag number.

17.4 Installation

1. Tape and float gaging shall be installed in accordance withDrawings 6S-6290, 6S-7238, and 9S-8976.

2. Float guide wire shall be installed plumb, properly centered, freeof kinks or twists, and pulled taut under proper spring tension.

3. Gages shall be mounted securely to tank shell with a sufficientnumber of brackets properly attached and adequately spaced to holdgage rigidly in place and in proper alignment at all points.

17.5 Safety

1. Electrical requirements for transmitters shall conform to GEMS K-1D.

2. Accessibility requirements for instruments shall conform to GEMS J-1D.

18. SERVO GAGES

18.1 Application

1. Servo gages are designed to perform level measurement relating tovolume measurement, not mass measurement.

2. Servo gages are typically used to provide continuous levelmeasurement of a process level or level indication/measurement atan interface.

3. Servo gages may be utilized in the following services:

a. Low or medium pressure applications, such as with atmosphericconditions.

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b. High pressure applications, such as with spheres or bullets.

4. Servo gages can be used when it is feasible to have displacer incontact with the process.

5. Standard measuring range for servo gages is 0 to 80 feet. Otheroptional ranges are available, normally 0 to 120 feet. Manufacturershall be consulted for ranges exceeding 120 feet.

18.2 Design

1. Electronics section of gage shall be isolated from drum housing tomaintain a product free electronics section and to be waterproof.

2. Drum housing shall not permit flow of gaseous vapors intoelectronics section.

3. Servo gages shall be rated for appropriate electrical areaclassification in accordance with the NEC and API RP 500.

4. Servo gages shall provide, at a minimum, high and low level alarmsetpoints, two motor setpoint alarms, and two DPDT dry contacts.Setpoints and dry contacts shall be user configurable on the benchor in the field.

5. Level measurement output shall preferably be a digital signal. Aproportional 4-20 mA signal may be utilized for transmitting to anon-servo gage manufacturer device.

6. Electronics shall have:

a. Radio frequency immunity (RFI) protection as follows:

(1) V/M field strength with frequencies from 20 to 500 MHz.

(2) Maximum variation of output signal from instrument undertest 0.5% of span.

b. Minimum vibration limits that conform to IEEE-344 seismiccertification requirements (approximately 1 g at 40 Hzfrequency).

c. Integral filter that is effective for approximately 40 dBattenuation at 4 Hz and higher frequency.

7. Servo gage shall be adequately protected against power surgesand/or lightning to prevent damage to servo gage and its internals.

8. Power requirements range from 24 VAC to 240 VAC at 50/60 Hz.

9. Type of displacer configuration shall consider if:

a. Product level is turbulent.

b. Stilling well can be feasibly installed.

c. Displacer utilized will be guided or non-guided.

10. Flange connection size shall be determined by displacer size(normally 2 inches to 6 inches in diameter).

11. Displacer diameter (2 inches to 6 inches) shall be as large aspossible to enhance accuracy of gage. Density characteristics shallbe considered in design.

12. Servo gages shall be able to compensate for wire weight anddisplacer size, drum deviations, roof movement, and tankdeformation. Compensation shall be provided as follows:

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a. If deformation of either the walls or movement of roof can becalculated, deformation can be compensated. Servo gagemounting shall be firmly connected to top course of roof.

b. If deformation is not known and cannot be calculated, anexternal support bracket can be utilized to minimize movementof servo gage on roof nozzle, or a stilling well can beinstalled to provide a firm mounting location for gage.

13. Servo gages shall have a connection for temperature or RTD inputand density input.

14. Calibration procedure for servo gages, using the servo gage itselfor using the remote indicator, shall be accomplished without havingto open instrument compartment and expose internals to theenvironment.

15. A tank gaging software system package specifically designed fortank inventory tracking and control shall be available on apersonal computer based system or instrument control system.

18.3 Materials and Construction

1. Servo compartment and cover shall meet or exceed design rating forapplicable service and atmospheric conditions.

2. Displacer, measuring wire, measuring drum and drum shaft, magneticseparation cap, and other internal parts shall have design ratingsthat meet or exceed applicable service conditions based onmanufacturer's recommendations and subject to Purchaser approval.

3. Displacer and drum compartment, including internals, shall normallybe 316 SS. Extremely corrosive services shall require corrosionresistant materials that shall be subject to Purchaser approval.

4. Flanged connections shall conform to ASME B16.5.

5. Servo gages shall have a stainless steel nameplate permanentlyattached and engraved with tag number, vessel number, and service.

6. Nameplate shall be attached with machined stainless steel screws.If attachment by screws is not possible, nameplate shall beattached with stainless steel wire.

18.4 Installation

18. 4 .1 General

1. Servo gages shall be mounted on an existing roof nozzle 2inches to 6 inches in diameter.

2. Calibration chamber (in lieu of direct nozzle mount) shallbe installed to assist in future calibrations ormaintenance of servo gage displacer assembly.

3. Stilling wells shall have perforations in accordance withmanufacturer's recommendations.

4. Parts of stilling well pipe not exposed to process withintank shall be coated to prevent corrosion.

18. 4 .2 Fixed and Floating Roof Tanks

1. Servo gages shall be preferably installed using a stillingwell.

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2. Stilling well shall be supported by tank bottom (providedtank bottom is firmly supported) and by wall near bottomof tank.

3. Stilling wells that penetrate roof top shall have flexibleseal to prevent loss of vapors from tank to atmosphere. Ifflexible seals are not permitted, stilling well shall bewelded to roof top nozzle and supported by wall nearbottom of tank.

4. If a stilling well cannot be installed, a servo gage witha non-guided displacer shall be used. Largest availablediameter displacer shall be used to enhance accuracy.

18. 4 .3 Pressurized Vessels and Tanks

1. Servo gages on pressurized vessels and tanks shallpreferably be installed using a block valve between nozzleand calibration chamber. (Note: Block valve will permitisolation of contents of pressurized vessel andatmosphere, allowing re-calibration or removal of servogage while vessel remains in service.)

2. A stilling well may be used to help minimize effects ofturbulence and increase accuracy of gage.

3. Stilling wells in spheres are supported by inside bottomof sphere.

4. Stilling wells in bullets are supported by the weld tonozzle and additional support brackets in accordance withmanufacturer's recommendations.

18.5 Safety

1. Electrical and instrumentation requirements shall conform to GEMSK-1D, K-13D, and L-1P.

2. Accessibility requirements shall conform to GEMS J-1D.