2 replies to this topic

[Falalo]

Hi all,
Just recently i have received a request to validate id UV ASME stamp on a psv is required or if this can be waived.

Is my understanding that the PSV can be design by API 520 and /or BPVC (ASME code), at same time that when you design them under BPVC, ASME stamp is required (following the rule that if is under the code has to be stamped).

But this case (common) really make me hesitate and make me post these questions:,
1.) How come a PSV that is installed on a pump, compressor or other rotative equipment not being installed or directly connected is design under BPVC?
2.) Shouldn't be design under API 520?
3.) Being these designed under BPVC, is required UV stamp in all cases without exeptions?
4.) Should this UV stamp be waived due the original vendor is not able to provide the certification?

Really appreciate your feed back in this matter

Eduardo

[ankur2061]

Falalo,

A brief but interesting discussion related to API vs UV stamped ASME PSVs can be read at the following link:

http://instrumentation.web.id/?p=676

Another link describing a UV stamped PSV according to ASME Section VIII (see "Type") is provided below:

http://en.wikipedia....ki/Safety_valve

Regards,
Ankur.

Edited by ankur2061, 20 November 2012 - 10:18 AM.

[kkala]

I am not quite aware of above queries, local Process does not deal with them. Following concerns views, supporting documents / examples are presented. Comments would be welcomed for a more precise picture.
1) Suppose a major piece of equipment follows ASME. Location of PSVs and their capacity should follow any requirements by ASME, PSV themselves can be designed and made either by ASME or another code (e.g. DIN). However the latter could create some issues, e.g. adapters on the interconnecting flanges. First option can be more convenient from technical viewpoint.
Examples: Offered DIN boiler was to be connected to ANSI piping at a distance ~0.5 m from drums (adaptors). BFW pump code changed from API 610 to DIN XXXX for lower cost. Electrical equipment per NEC could be installed per IEC (minor issues would be solved, e.g. on cables).
2) API RP 520 / 521 are widely applied internationally (API 526 unfamiliar to me). There are other standards on same subject (e.g. BS 6759, EN 1268), I do not know whether they are really different.
3) Not in all cases is stamp required on PSVs, see http://www.eng-tips....cfm?qid=265864.
Also useful http://instrumentation.web.id/?p=676 .
It seems cases of mandatory stamping are increasing with time (depending on state, use, etc). Look at http://www.absa.ca/f...ts document.pdf - search for "stamp".
Example: In ~2000 a locally installed ASME boiler was not stamped to avoid incurring cost, http://www.cheresources.com/invision/topic/12841-double-wall-pipe-pressure-vessel/ - post No 4.
4) I think Vendor has to provide the necessary certificates for ASME, whether PSV is to be stamped or not. Then "stamping" has be by a third inspector (that's why it incurs expenses). Vendor is accountable, if it delays the certificates.

Edited by kkala, 20 November 2012 - 12:03 PM.