8 replies to this topic

[J_Leo]

Hello Friends,

 

For a horizontal drum such as LPG storage bullet, when it is more than 100 ft long, what length would you consider for fire scenario? It would be less than 80 ft per API 521 defined fire zone of 5000ft^2 if it is applicable to a single vessel.

 

Can we size the PSV considering only 80 ft of the drum length plus one head for fire scenario?

 

 

Thanks,

Leo

[Bobby Strain]

If you look carefully at the API defined fire zone, it mentions nothing about a circle.

 

Bobby

[latexman]

For a horizontal drum such as LPG storage bullet, when it is more than 100 ft long, what length would you consider for fire scenario? It would be less than 80 ft per API 521 defined fire zone of 5000ft^2 if it is applicable to a single vessel.

 

Can we size the PSV considering only 80 ft of the drum length plus one head for fire scenario?

 

No, because it is not applicable to a single vessel/source.  That guidance includes "consideration of the actual layout of facilities, the location of sources of combustibles, the provision of drainage and the effects of natural barriers".

[J_Leo]

Bobby and Latexman,

 

Thank you so much for quick responses. Great points! I am glad to see you are still here helping fellow engineers like me.

 

By the way, is API 521 the standard used for drawing fire circle in a plant? I saw those but never done one myself.

 

Regards,

Leo

[Bobby Strain]

Why do your keep talking about a "fire circle". There is no mention of "circle" in API 521.

 

Bobby

[breizh]

Hi Bobby ,

I believe he is talking about Zoning in reference to areas classification ( flammable area, explosive area ,..)

https://www.hse.gov....easareaclas.htm

 

My  understanding 

Breizh 

[Bobby Strain]

Breizh,

     I think that he believes, like most chemical engineers, that the zone is indeed a circle. That was always the thinking of most engineers with whom I worked over the years. And none, to my knowledge, ever asked for clarification. One would think that the API group would have clarified the meaning over these many years. But, maybe, they, too, believe it to be a circle!

 

Bobby

[J_Leo]

Breizh,

 

Thank you for the reference.

Hi Bobby ,

I believe he is talking about Zoning in reference to areas classification ( flammable area, explosive area ,..)

https://www.hse.gov....easareaclas.htm

 

My  understanding 

Breizh 

[J_Leo]

Of course, fire would not be a circle. However, the EPC companies make fire circles when sizing flare sub-header or headers.

 

     I think that he believes, like most chemical engineers, that the zone is indeed a circle. That was always the thinking of most engineers with whom I worked over the years. And none, to my knowledge, ever asked for clarification. One would think that the API group would have clarified the meaning over these many years. But, maybe, they, too, believe it to be a circle!

 

Bobby