Previous in Forum: Axial Flow Fans   Next in Forum: VTP Thrust
Close

Comments Format:






Change Mode
Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







Add Vote
7 comments
Rate Comments: Nested
jinsonmc2004
Member

Join Date: Aug 2009
Posts: 9

Ball Valve Test Pressure

09/22/2009 8:24 AM

I have asked my supplier for ball valves 1" Size # 300 A 216 WCB Body SS Ball , the operating pressure of the line is 45 barg . The valves are now delivered and in the test and guarantee certificate it is writted hydrotest pressure 450 PSIG for body and for seat 315 PSIG. the pipe spools where the valves will be installed are tested for 1.2 X design pressure . So is it ok for the valves body and seat to be tested at low pressure ? what does the code says?
Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Good Answers:

These comments received enough positive votes to make them "good answers".
2
lyn
Guru

Join Date: Oct 2008
Posts: 42355
Good Answers: 1693
#1

Re: Ball Valves Test Pressure

09/22/2009 8:29 AM

You are operating at 45 barg but want to use valves rated for 30 barg?

You are out of your mind!!!!!!!!!!!!!!!!!
Register to Reply Good Answer (Score 2)
Go to Next Good Answer
RVZ717
Guru
United States - Member - USA! Hobbies - Musician - Sound Man Engineering Fields - Mechanical Engineering - More than a Hobby Technical Fields - Technical Writing - New Member

Join Date: Oct 2008
Location: City of Roses.
Posts: 2056
Good Answers: 101
#2
In reply to #1

Re: Ball Valves Test Pressure

09/22/2009 2:24 PM

Only 21.79 BarG rating on the seats even!

"You are out of your mind!!!!!!!!!!!!!!!!!"

I Concur.

__________________
 Don't believe everything you read on the Internet!
Register to Reply
YesMAM
Power-User

Join Date: Jun 2009
Location: Land o' Lincoln
Posts: 124
Good Answers: 7
#3

Re: Ball Valve Test Pressure

09/23/2009 12:05 AM

The valves you have specified have a nominal 300 psig (300#, or #300) rating [20.69 barg]. They are hydrotested to 1.5 x design rating. You have not specified if these are flanged, threaded, or socket welded valves. You have not specified what is in the piping (steam, water, compressed air, compressed gas). You have not specified the operating/design temperature (design rating is based on temperature as well as pressure, so if the temperature is over ambient, the design pressure is derated to a lower value). Installing these valves in your system will likely lead to very rapid failure, possible injury to anyone in the area, and, if the material in the piping is hazardous, a very serious situation. As a minimum you need to specify valves with much higher rating (perhaps 900 psig).

To echo lynlynch and RVZ717, you are out of your mind if you intend to use these valves.

__________________
 If you can't do it right the first time ... do it wrong, then let the professionals fix it.
Register to Reply
The Prof
Guru
Engineering Fields - Mechanical Engineering - New Member Hobbies - CNC - New Member

Join Date: Aug 2006
Location: Western Australia
Posts: 767
Good Answers: 58
#6
In reply to #3

Re: Ball Valve Test Pressure

09/24/2009 3:38 AM

300# classification has nothing whatsoever to do with pressure rating.

__________________
 If you can't explain it simply, you don't understand it well enough. (A.E.)
Register to Reply
jinsonmc2004
Member

Join Date: Aug 2009
Posts: 9
#4

Re: Ball Valve Test Pressure

09/23/2009 3:20 AM

i have already retured the valves as the physical quality of the valve did not pass the QC Inspection test. I have specified the supplier for Natural Gas Purpose #300 Flanged Type. The irony is that as per the Test certificate for # 150 & for #300 they have hydrotested the valves with same pressure of 450 and 315 PSIG Respectively
Register to Reply
3
Abdel Halim Galala
Guru
Engineering Fields - Piping Design Engineering - New Member Egypt - Member - Member since 02/18/2007

Join Date: Feb 2007
Location: Cairo, Egypt
Posts: 1733
Good Answers: 248
#5

Re: Ball Valve Test Pressure

09/23/2009 12:37 PM

● I'd like to declare the meaning of Class 300, Rate 300, or 300#, all bear the same meaning, but this meaning excluding the pressure which the valve can withstand as a lot of us thinking that it means a 300 psi nor 20.69 bar as derived at your thread. For more details for that meaning, please refer to CR4 Thread Pound Rating.

● Per API 6D, Para. 10.3 Hydrostatic shell test: Hydrostatic shell testing shall be performed on the fully assembled valve prior to painting Valves shall be closed off and the obturator placed in the partially open position during the test. If specified by the purchaser, the method of closing the ends shall permit the transmission of the full-pressure force acting on the end blanks to the valve body. Where present, external relief valves shall be removed and their connections plugged.

The test pressure shall be 1.5 or more times the pressure rating determined in accordance with 6.1 for material at 38°C (100°F). The duration shall not be less than that specified in Table 10.

● Per ASME B16.34: Each valve shall l be given a shell test at a gage pressure no less than 1.5 times the1 00°F rating, rounded of to the next higher 25 psi increment. The test shall be made with water, which may contain a corrosion inhibitor, with kerosene, or with other suitable fluid, provided such fluids has viscosity not greater than that of water, at a temperature not above 125°F. Visual detectable leakage through pressure boundary walls not acceptable. Test duration shall be not less than shown below.

● From ASME B16.34, Table 2-1.1 (Rating for Group 1.1 Materials such as A216 Grade WCB), at ambient temp. the valve class 300 can withstand a working pressure up to 740 psi ( 51 bar).

__________________
 It is better to be defeated on principles, than to win on lies!
Register to Reply Good Answer (Score 3)
No more Good Answers.
The Prof
Guru
Engineering Fields - Mechanical Engineering - New Member Hobbies - CNC - New Member

Join Date: Aug 2006
Location: Western Australia
Posts: 767
Good Answers: 58
#7
In reply to #5

Re: Ball Valve Test Pressure

09/24/2009 3:42 AM

GA as usual - sorry, I did not read the whole thread before commenting, but the concept that the these # ratings can be translated into PSI allowed just had to be corrected in this thread. You did it better.

__________________
 If you can't explain it simply, you don't understand it well enough. (A.E.)
Register to Reply
Register to Reply
Have a Different Question?
7 comments

Good Answers:

These comments received enough positive votes to make them "good answers".
Copy to Clipboard

Users who posted comments:

Abdel Halim Galala (1); jinsonmc2004 (1); lyn (1); RVZ717 (1); The Prof (2); YesMAM (1)

Previous in Forum: Axial Flow Fans   Next in Forum: VTP Thrust
You might be interested in: Pressure Relief Valves, Gas Valves, Industrial Valves

Advertisement

Got Something to Say?
Ask a Question
Start a Discussion

Search this Forum
Mechanical Engineering:
Go

CR4 Sections
Aerospace
BioMech & BioMed
Chemical & Material Science
Civil Engineering
Communications & Electronics
Education and Engineering Careers
Electrical Engineering
General Discussion
Instrumentation
Manufacturing
Mechanical Engineering
New Technologies & Research
Software & Programming
Sustainable Engineering
Transportation

Site Directories
Forum Directory
Blog Directory
User Group Directory
RSS Feeds

CR4 Rules of Conduct
CR4 FAQ
Site Glossary

Who's Online (92 right now)
Show Members
Advertisement