pneumatic testing presentation

7/31/2019 Pneumatic Testing Presentation

1/26

ABSAthe pressure equipment safety authority

Pneum at ic Test ing

Presented by:

Djordje Srnic, Manager of Design Survey

Code Update Seminar

Edmonton, October 05, 2010

Calgary, October 07, 2010


2/26

2

Objectives

Understand

Purpose of Pressure Testing

Regulat ion Requirem ent s

Hydrostatic vs. Pneumatic Test

Risk

Pneum at ic Testing Specific Requirem ent s

Registrat ion Requirem ent s


3/26

3

To verify

system integrity

leak tightness

What is the Purpose of Pressure

Testing?


4/26

4

Why Pressure testing is required?

The last physical quality test in thefabrication process

Performed prior to placing the system into service

Done in controlled environment

Preferred mainly due to safety

considerations


5/26

5

Regulation Requirements

Section 3 0 of PESR 4 9 / 2 0 0 6(1)All pressure piping leak tests must be conducted usingthe hydrostatic method.

(2)Despite subsection (1), the Administrator may accept,for a specific pressure piping system, alternative testmethods that are allowed in a code or standard that isdeclared in force.(3)A pressure piping system shall not be tested at atemperature that is colder than its minimum designtemperature.

(4)When conducting pressure tests, the ductile-to-brittletransition temperature and the possibility of brittle fracturemust be considered by the contractor.


6/26

6

Alternative test Methods

Pneum at ic te st

Hydrosta tic- Pneum at ic Test

I nit ial Service Lea k Test

Sensitive Leak Test

Alternative Test Methods in Lieu ofHydrostatic Leak Testing for a Closure or

Tie- I n W elds


7/26

7

Why Pneumatic Testing is

Alternative to Hydrostatic Test?

Difficulties w ith hydrostat ic te stingSupply & disposal of water, disposal of fluidadditives

Water leak can cause equipment damageFreeze susceptibilityStructural support limitationsContaminationOperational impacts - process contaminant

Affect dry-out of internal refractory liningsAvailability a ir is re adily available ,clean


8/26

8

Hydrostatic vs. Pneumatic Test

Qualitative Differences

Water is not compressibleEnergy storage is minimalPressure changes finite amount by infinitesimal

change in volumeWater filled balloon does not pop nocompressive energy

Air is compressibleEnergy storage is large

Pressure change proportional to volumechangeAir filled balloon pops large, instantaneousenergy release


9/26

9

Risk


10/26

10

Dangers Associated With

Pneumatic Testing


11/26

11

Primary concerns

Pressure wave

Flying debris


12/26

12

Damage correlation

0.04 psi Very loud noise [143 dB], sonic boom glass failure0.10 Breakage of small windows under strain0.15 Typical glass pressure induced failure0.30 10% of windows broken0.50 Windows shattered, minor damage to house structures0.70 Upper limit for reversible effects on humans1.0 Partial demolition of houses2.0 Partial collapse of walls and roofs of houses2.4 Eardrum rupture

2.5 Threshold for significant human lethality3.0 Steel frame building distorted and pulled away from

foundation


13/26

13

Flying Debris

Fragmentation Criteria

Primary fragments

Secondary fragments


14/26

14

Pneum at ic Test Procedure ( PTP)

Registration is Required

De sign Survey w ill review and register PTP if

p>315 psi oror

V>0.5m3

oror

Company does not have Standard PTP included intheir quality program and piping system p=


15/26

15

Pneumatic Test Procedure Must

Provide technical justification for not completingthe hydrostatic pressure test.

Provide a w rit te n te st procedure that w ill fullyaddress the technical and safety considerationsfor the test.

Be acceptab le to the ow ner. The ow ner of thepiping system must review the circumstancesand decide to accept the risk of nothydrostatically testing the piping system

Be review ed and accepted by ABSA.


16/26

16

Technical and Safety

Considerations

De fine test boundaries ( List of piping & Pressurevessels included in the test)

Define system volume and test fluidCalculate test pressure

Pressure re lief devices ( m ax set pressure at1 1 0 % of the te st pressure )

Safet y pre cau tions ( safe dista nce, bar ricades,

marking the test area, hours when test may beconducted, w ork ing & eva cuation procedures,etc.)


17/26

17

Technical and Safety

Considerat ions ( cont d)

Steps to minimize the chance of brittle failureduring a pneumatic test

List of all personnel allow ed w ith in test ing ar ea ,requ ired training and com petences

Precautions taken to prevent gas expansiontemperature drop and thermal stress due thermalgradients

Me thod of testing w ith details of pre ssure steps,holding time, inspection methods, depressurizing

Test accept ance criter ia and records ( creat ing andm ainta ining records)


18/26

18

Test Pressure

P t = 1 .1 x P x Sat/ SdtPt = test pressure

P = Maximum allowable working pressure

Sat = Allowable stress at the testtemperature

Sdt = Allowable stress at the design

Temperature


19/26

19

Methodologies for Defining Safe

Distance

EPC companies have their own standards& methods

End users have their own standardsNASA method

US DOD method

ASME PCC-2 Article 5.1 method


20/26

20

Common Safe Distance Analysis

for Pneumatic Test

Define system volume and test fluid

Calculate test pressure

Calculate stored energy

Define equivalent amount of TNT

Calculate the safe distance


21/26

21

Example:

Air; p= 3 1 5 psi; V= 0 .5 m 3

Stored energy = 1,677 kJ

TNT equivalent = 0.393 kgSafe distance according to:

US DOD method - R = 18.1 [m]

NASA method - R = 19.8 [m]

ASME PCC-2 method - R = 14.7 [m] ** R = 30 [m] because stored energy is

E=1,677 [kJ] < 135,500 [kJ]


22/26

22

ABSA is considering Using the

Equivalent Stored Energy

E= 1 ,6 7 7 [ kJ] for piping syste m w ithp= 3 1 5 [ psi] and V= 0 .5 [ m 3 ]

Graphed stored energy for combinationof volum e and pressure w hich w ouldcreate the same stored energy as piping

system w ith p= 3 1 5 [ psi] and V= 0 .5 [ m 3 ]


23/26

23

Graph


24/26

24

Conclusion

Knowledge of Regulation requirements

Understanding the Risk

Competency of personnel

Understanding technical and safety

considerations

Deve lopm ent and I m plem ent at ion of te st

procedure ( before , during and aft er thetest)


25/26

25


26/26

26

Questions

pneumatic testing presentation

Documents