×
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

OPERATING AND DESIGN PRESSURE/TEMPRATURE

OPERATING AND DESIGN PRESSURE/TEMPRATURE

OPERATING AND DESIGN PRESSURE/TEMPRATURE

(OP)
hellow,
in our project in blowdown line the operating temprature
is more than design temprature.
some body how is it possible.

RE: OPERATING AND DESIGN PRESSURE/TEMPRATURE

Poor design?

Best regards

Morten

RE: OPERATING AND DESIGN PRESSURE/TEMPRATURE

(OP)
Dear MortenA
we cannot say:poor design I think it is related to firecase
relief study because maximum operating temp. will be happend
in this case.but actually I dont have any information about that.
Regards
sadra

RE: OPERATING AND DESIGN PRESSURE/TEMPRATURE

Normally, the PSV and its piping system are not designed for fire case but at the maximum operating Pressure and Temperature plus margin.  When the system exposes to fire, the temperature in the pipe may exceed the specified design temperature.  However, this can not be considered as normal operating temperature but upset conditions.  The piping is derated at high temperature.  However, ANSI B31.8 (if I recall it right) allows the piping to expose to an upset pressure of 20% or even 33% of its design pressure for a certain times and hours in a year.  If the pressure associated with the upset temperature falls below the allowance above, the piping design is still OK.
Cheers,
TAD123

RE: OPERATING AND DESIGN PRESSURE/TEMPRATURE

I agree with tad - you should then print Operating case: Fire relief

Remember that if you are in europe theres a new pressure vesselv directive that overrules the old api 520 "fire case" 21% - now it alway (no exceptions) max 10%

Best regards

Morten

RE: OPERATING AND DESIGN PRESSURE/TEMPRATURE

B31.3 allows short term excursions to 120% and 133%.  B31.8 is limited to 10% I believe, definitely not 20% or 33%.

RE: OPERATING AND DESIGN PRESSURE/TEMPRATURE

Sadra,

Do you think it may be possible that the design case temperature for your blow-down system is a minimum temperature chosen to account for the JT effect of the relieving gas?  It might have an effect on the materials and welding procedures selected for this service.

Regards,

Gunnar  

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