Fresh water in contact with SS tank - API 650

[Eduardo1982]

Dear Guys. According to API 650, S Annex (S.4.10.4) - For hydrotest water quality - When testing other fresh water, the exposure time shall not exceed 7 days.. what it means? Currently I am going to test a tank of 22000 m3 (Stainless Steel) with a non potable water but with the quality enough to fulfil quality of S.4.10.2 (a). However, exposure time is higher than 7 days. Should I treat this water adding chemicals? Is there any paragraph in API 650 to establish this treatment?

 

[MJCronin]

Suggest that you contact the local tank fabricator to get his experience with exposure time and water purity.

A lot depends on how you count exposure time. I would not begin the clock when the first gallon of hydrotest water goes into the tank. I would start the clock when the tank is full.

Why must you need more than 7 days to hydrotest the tank ? Are you taking a long, long time to fill the tank ? Have you considered auxiliary pumps ???

https://www.eng-tips.com/viewthread.cfm?qid=179224

https://www.eng-tips.com/viewthread.cfm?qid=352353

https://www.corrosionguru.com/wp-content/uploads/2017/02/Hydrotest-Water.pdf

Please respect us ..... Let us know what your final decision is on this important topic

MJCronin
Sr. Process Engineer

 

[Eduardo1982]

Well.. it is taking a lot time due to logistics and project distance´s of water sources.

 

[bimr]

As a minimum, you need to add a disinfectant. If the water is of potable quality, that is all that is required.