×
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

Acid number progression during TOST test

Acid number progression during TOST test

Acid number progression during TOST test

(OP)
I am preparing a specification for turbine oil for use in our hydroelectric generators. Our guide specification calls for a maximum acid number of 0.5 mg KOH/g after 1000 hours TOST. Most literature lists the the total TOST time or time to reach 2.0mg KOH/g. Does anybody know what the acid number vs. time graph looks like for high quality R&O inhibited turbine oil? I would expect to see something like a slow increase for about 2/3 of the total time followed by a rapid increase in the acid number. I'm trying to get an idea of where the 0.5 mg KOH/g point would fall on the time scale in percent total time. This would allow me to estimate if the product being considered would meet or exceed our oxidation resistance specifications.

Thanks,

Tom Moritz
Mechanical Engineer
US Bureau of Reclamation

RE: Acid number progression during TOST test

Does the TOST ASTM standard (D-943) say anything about it?

=====================================
Eng-tips forums: The best place on the web for engineering discussions.

RE: Acid number progression during TOST test

(OP)
D-943 requires the analyst test the acid number starting at 500 hours then at least once every 168 hours (one week) thereafter until 3000 hours.  After 3000 hours the analyst can reduce the frequency of AN testing to once every 500 hours.  There is a formula to calculate the TOST duration if the AN exceeds 2.0mg KOH/g inbetween AN tests.

I posted this question because all I've seen are the end results, the total duration to the 2.0mg KOH/g acidity level.  I assume a certified lab would record the intermediate test results to document their testing procedure.  I'm wondering if anybody else has seen a chart of AN vs. TOST time.  If so, what does the curve look like.

Thanks,

Tom Moritz
Mechanical Engineer
US Bureau of Reclamation

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