4 replies to this topic

[tsrc8204]

What difference between API520 and API521? Which standards could be apply for sizing or calculating safety valves or thermal relief valves? Please advise and thank to all in advance.

 

tsrc8204.

[fallah]

Hi,

 

In beirf, API 521 included "Pressure Relieving and Depressuring Systems" and discucess about overpresuure scenarios and relevant relief loads determination; while API 520 included sizing and installation of the pressue relieving devices. Then, obviously API 520 is applied for sizing the pressure relieving devices...

[tsrc8204]

Dear Naser,

 

Thanks for your explanation for mu doubt. So, I need to make sure which cases or overpresuure scenarios in API521; and then sizing  relieving devices by API520 code? Is is correct for my understanding?

 

Regards,

tsrc8204.

[fallah]

tsrc8204,

 

Yes, at first you need to specify credible scenarios by process system analysis and then determine the relief load for each scenario as per the methods included in API 521. Then using API 520 by determination needed relief area for each case you can specify governing scenario which is the case with highest relief area. It is considered as preliminary sizing and it should be reflected in relevant PSV data sheet for submitting to vendor for final PSV sizing and selection... 

[tsrc8204]

Dear Fallah,

 

I got it and very appreciate your supporting.

 

tsrc8204.