Hydrotest Water quality

[PaulTheMechGuy]

I need to meet a 20 ppm max chloride content for water used for hydrotesting a pressure vessel we are manufacturing. The customers requirement says potable water is required. We've had the water coming into our plant tested and the chlorides are consistantly around 70 ppm. Does anyone else have this problem? Where do you get your water from to meet low chloride requirements? We have another job coming through requiring less than 2 ppm.

 

[BUTCHCWIQAM]

They need to build a DI water skid there is some tank Manufactures that use this to keep chlorides down.
70 sounded high I have inspected some tanks in upstate NY and water, there were 35 ppm and I though that was high, I believe that the DI water was below 15ppm, and I will check if needed.

 

[vesselfab]

70 is high

our city water is typically around 25 ppm

 

[gr2vessels]

Paul,
You might need to transport the vessel to a place where you can access potable water. Perhaps transfer the tap water first to an open top tank, to allow evaporation of chlorine, then measure the actual chlorides content. If is marginally higher, like say 25 ppm, you could ask the Client for approval, once you proved the good intent of complying. The higher limit of 35 ppm should be tolerated at ambient temperature even by SS 304/316, provided that you flush with demin water the vessel after the hydrotest and dry it quickly without hot air input.
cheers,
gr2vessels

 

[racookpe1978]

Recheck with your customer: He may NEED "pure" water for his process -> so DI water is essential, regardless of cost. If so, ask if you can FILL and FLUSH with your "dirty" Cl water several times, hydro with it, HTEN drain and flush with "pure" DI water before delivery to him (ship empty of course).

Or fill and flush and hydro with your potable water at your site, drain and "wipe down" the internals if he's really picky, ship empty, and let HIM fill it with HIS expensive DI water on site.

Or he may only want potable water because of cleanliness and sanitaiton concerns - regardless of Cl levels - because the chloride levels are really irrelevent. But he didn't think about the cost of DI water.

Regardless, you MUST fill and flush (several times probably) before the tank is clean enough for the "final" DI water hydro.

 

[GenB]

on ss and other exotic metals you need low chlorides in the water for hydro.talk to a water conditioning specialist,
depending on the size of the vesel,
you may be able to install a soft water system will provide resin and carbon to take the chemicals out.
you can rent a system.-

rather than test with tap water and ruin the vessel by shorten its life span or even destroy it.
check with its the Code and good eng practice to do what we suppose to do...

check with NACE WEB SITE OR OTHER ENG-TIPS FORUMS RE CORROSSION

 

[MTPipeliner]

In the past when confronted with the potable, non-chlorinated water issue I've used untreated well water that is considered potable. Depending on where in the world you are this may be pretty difficult to find. Might be worth checking in to.