HYDROTEST WATER QUALITY

MOKRANI · **Joined:** Thu Sep 22, 2011 6:51 pm **Posts:** 2

Is there any limits by ASME IIIV Div 1 for the hydrotest water quality to be used in SS 316L vessel???

Javed Nasir · **Posted:** Fri Sep 23, 2011 2:46 pm

No as far as Section VIII-1 is concerned.

kotharilm · **Posted:** Tue Nov 08, 2011 1:46 am

Mokrani,
If you are holding/passing thru something in any case it should not react but
in this case of SS it should be Cl free (i.e.Less than 16ppm)

Rathnam · **Joined:** Fri Jul 09, 2010 7:57 am **Posts:** 79

I do not understand this ppm spec of chloride level for SS vessels.
Also ,this ppm level keeps varying depending on who specifies.

I suppose , potable water has to be arranged for Hydrotest.
Still , potable water may not meet this spec . Any how one tries to meet this condition.

Is it the contention that exposure to chloride for few hours during Hydrotest
will damage the vessel ? If that be so ,perhaps during operation the process
fluid is going to be restricted to this ppm level ? If that be the the case then
you are better off using Carbon steel where such concerns are not there ?

The vessel after Hydrotest would be dried and also would receive a passivation treatment .
So why should chloride level matter ?

API 650 specifies 50 ppm chloride level of test water for storage tanks.
This makes sense as complete drying is not assured for such large tanks.

niraj_kuwait · **Posted:** Sat Nov 19, 2011 8:04 am

Hydro test water quality is V Imp can't Ignore if you will do Passivation.
Reason is
Passviaton is process to create passive layer on SS surface in size of Angstrom unit which resist Oxidation .

But what about already impregnated inside during your hydro test,

Answer is Pickeling

But again by Pickeling can't be 100 % sure of removing impregnated Chlorides in may be some micrones opened cavity on surface.

IF--- It remains over there Then Best food for Crevices corrosion.

This all above are IF & BUT chances which Good engineering practice are not allowing ,
Since ASME is silent about Water quality.
Thanks

Rathnam · **Joined:** Fri Jul 09, 2010 7:57 am **Posts:** 79

Code:

Appendix S , API 650
S 4.10 Hydrostatic testing 
S.4.10.2 The materials used in the construction of stainless steel tanks may be subject to severe pitting, cracking, or rusting if they are exposed to contaminated test water for extended periods of time. The Purchaser shall specify a minimum quality of test water that conforms to the following requirements:
a. Unless otherwise specified by the Purchaser, water used for hydrostatic testing of tanks shall be potable and treated, containing at least 0.2 parts per million free chlorine.
b. Water shall be substantially clean and clear.
c. Water shall have no objectionable odor (that is, no hydrogen sulfide).
d. Water pH shall be between 6 and 8.3.
e. Water temperature shall be below 50°C (120°F).
f. The chloride content of the water shall be below 50 parts per million, unless specified other wise by the Purchaser.
S.4.10.3 When testing with potable water, the exposure time shall not exceed 21 days, unless specified otherwise by the Purchaser.
S.4.10.4 When testing with other fresh waters, the exposure time shall not exceed 7 days.
S.4.10.5 Upon completion of the hydrostatic test, water shall be completely drained. Wetted surfaces shall be washed with potable water when nonpotable water is used for the test and completely dried. Particular attention shall be given to low spots, crevices, and similar areas. Hot air drying is not permitted.

kotharilm · **Posted:** Fri Mar 23, 2012 4:59 pm

Hydro testing holding time also varies(…+++ side) and as holding time increases the parameter of hydro testing become more and more stringent if Chlorides is 30 PPM ….chlorine …etc ppm as per code and holding time is 04 hrs but if holding time is increases or pre ,stage and final hydro testing is added means vessel …,piping etc..ie ss material is exposed so many times then limit is very much stringent.
In cross country piping holding time is 24 Hrs is common but lent and dia is very huge and for only filling of takes days iin this condition water is should be chlorine free and chloride is kept ALAP and some corrosion inhibitor also added even this material not SS.
So please do complete exercise before doing any type of testing

HYDROTEST WATER QUALITY

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