Pressure Vessel Standards 3

[swertel]

I am looking for the ASTM (or other) standard for pressure vessel design and safety considerations. Specifically, I want to know if there is a recommended factor of safety for pressure vessels -- I remember it to be 3, but I can't recall from where. -- and proof testing methods, including frequency. In other words, before I put the pressure vessel in use, to what pressure must I test it for leaks? Once the vessel is in use, how often do I have to inspect it: 90 days, 180 days, yearly?

I searched the ASTM web sight by title ("pressure vessels&quot and came up with 112 possible standards. I could really use some help in narrowing my search.

The vessel will be made of stainless steel, hold a volume of 19 in^3, and be used in a hydrostatic test fixture as an accumulator that can see 40 ksi.

Thanks in advance,

--Scott

 

[designengg]

Please source ASME-section-VIII code, which is applicable unfired pressure vessel design.
This code requires one to consider allowable stress to be 25 % of the ultimate tensile stress, thus giving safety factor of 4.
Equipments designed as per ASME Section VIII are hydraulically or pneumatically tested to 1.5 tims the design presure for at least half an hour.

 

[prex]

ASME VIII Div.1 is your reference.
However your vessel is so small that will likely be outside the scope of any pressure vessel standard, so that you can design and test it to whatever criteria you want.
Keep also in mind that the first usage of ASME VIII (as any other pressure vessel standard) is quite difficult for a non experienced user: I strongly suggest you to consult first one of the available books on pressure vessel design.
prex
motori@xcalcsREMOVE.com

http://www.xcalcs.com

Online tools for structural design

 

[MJCronin]

All of the above information is correct, good and useful.

You may want to contract an individual or firm with more experience and then get a preliminary cost quote from an ASME cetrified fabricator.

With regard to testing, the first hydro test of the vessel is done as an initial certification and must be available to the certifying inspector. Any subsquent pressure tests are doe on a periodic basis and are usually part of an OSHA required "Mechanical Integrity" program. Rather than viewing and searching ASTM sites, I suggest the following:

http://www.asme.org

http://www.nationalboard.org

http://www.osha-slc.gov/SLTC/pressurevessels/index.html

and there are many others....

Good Luck


MJC

 

[butelja]

With a design pressure of 40 ksi, this sounds beyond ASME Sec VIII, Div.1 and Sec VIII, Div. 2. The methodology in ASME Sec VIII, Div. 3 may be most applicable. In my understanding, Div 1 is usually used up to 3000 psi, Div 2 between 3000-10,000 psi, and Div 3 above 10,000 PSI.

 

[doofleydangar]

The two standards worked to in the UK are BS 5500 and ASME IIIV Division. I do not know the latest editions, but bot refer to "Unfired Fusion Welded Pressure Vessels"

 

[doofleydangar]

The two standards worked to in the UK are BS 5500 and ASME VIII Division 1. I do not know the latest editions, but both refer to "Unfired Fusion Welded Pressure Vessels"

 

[welding1]

You may find the European Pressure Equipment Directive useful when considering the design of any pressure vessel. It's European law and states how design stresses must be derived for European application. It is also a very good reference; it covers hazard analysis, the basis for experimental design and a lot of other useful information on the design of pressure equipment. It does not include detail design, such as calculation rules for thickness etc.

If you come to my site;

http://www.gowelding.com

and follow the link for PED Directive, you will find a link to the Directive in pdf format on the UK DTI site. It's FREE to down load.

Have Fun

 

[akmal]

I would like to know where (in which clause) in ASME Section VIII is it stated that "the duration of hydro/pneumatic testing would be for at least half an hour" as stated by designengg on Sep 29 2001. Thanks in advance for your help.

Cheers,
akmal

 

[prex]

To akmal
Why don't you start a new thread for a new question, possibly in the Boiler and PV Eng. forum?
To come to your question there is no such provision, as far as I can remember, in the ASME VIII. I suppose there is one in some of the piping B31 codes, but cannot check at the moment.
I know also that is customary to find such a requirement in many pressure vessel supply specifications.
I think this comes from the confusion between proof (structural) testing (the only one required by ASME VIII) and leak testing.
In the former the duration is unimportant, as a structural failure would occur almost istantaneously, in the latter it is, as leaks might develop over time.
prex
motori@xcalcsREMOVE.com

http://www.xcalcs.com

Online tools for structural design

 

[swertel]

Have you also looked through the NBIC? (National Board Inspection Code -- ANSI/NB-23) There may be something in there about duration of tests, but in the context of prex's comments I believe.

--Scott

 

[rocco]

Dear SIr,

you can you advise on the BS for units at 0.95cc and how my company make obtain EU stamping of unit to sell in UK?

Regards
RE

 

[engrdon]

swertel,

There is no required duration of the hydrotest given in the ASME Code. The duration is something agreed upon by the client and the fabricator. However, we have used a duration of one hour for the hydrotest. We have used this approach for many years. If the vessel is going to leak it always happens within that time.

engrdon

 

We are hydrotesting for air compressor & gas compressor components
hydrotest pressure is 1.5 times the working pressure
burst pressure is 3.5 to 6 times
hydro test time is 30 minutes
menon1946@hotmail.com

 

[colinlove]

The Pressure Systems Regulations specify that all pressure vessels should be subject to a working and a through examination. The period betweeen examinations is specified on the Written System of Work.

 

[235zzzo]

Hello Forum

You can use also the AD MERKBLATT Code, from Germany, I think it is a very efficient one for pressure vessel mechanical calculations. It gives smaller thickness for the same work conditions, compared to the ASME, Section VIII. I use it in first place, unless the ASME is initially required.
Cheers
zzzo