×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Hydro Water Quality

Hydro Water Quality

Hydro Water Quality

(OP)
When specifying a fab shop hydro of pressure parts, do you require a minimum level of water quality? request fabricators procedure? or use a water quality standard?  Thanx in advance

RE: Hydro Water Quality

Yes we do. We specify treated water or potable water with a maximum chloride content. Also, after hydrostatic testing we specify drying.

RE: Hydro Water Quality

In addition to metengr's comment, the max chloride content should be limited to 30ppmw max if the steel is high alloy such as austenitic S.S.  For run of the mill C.S. you have a choice to specify 100 to 150 ppmw.  Some companies specifies 50 ppmw for C.S.   I think 50 is too strict for C.S.  Frankly, I don't know on what basis those companies can spec it so strict.

Yes, your document deliverables from the vendor should always include the hydrotest proceedure to review.  Hope this helped you.

RE: Hydro Water Quality

Another addition is the correlation between the test water quality and the drying as mentioned above.
The low chloride level is not enough for hydrotesting the Austenitic S/S vessels, particularly the ones with lots of crevices and areas where water can accumulate and stand. The draining only will retain in crevices the water, which in turn will slowly evaporate, thus concentrating the chlorides in the most vulnerable locations, perhaps over days and days time. This will suffice for the start of a local chloride induced cracking.
Another bad practice is the use of hot air to dry the vessel;- the temperature increase will accelerate the evaporation process, but same time increase also the chance of chloride attack, this time at higher temperature, at a faster rate than otherwise would happen. The results are the same..If possible, a rinse or flushing with demin water could reduce the chance of chloride attack considerably.
I am also developing a vacuum drying process at normal temperature. The results so far are excellent, are independent of the day's relative humidity and far better results for long term storage than any other current procedure. Providing a proper sealing of all openings, it eliminates the need for N2 blanketing, monitoring of N2 supply, etc..

Howzat?

Cheers,
gr2vessels

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources