Mounded Bullet - Fire sizing relief valves

[kvbalu]

Pls refer to below thread.

thread794-179601

Would be interested on more suggestions from members.

 

[Latexman]

I'd say there is no credible fire case.

Good luck,
Latexman

 

[stookeyfpe]

NFPA 58 still require a pressure relief device but permits its flow rate to be derated by 70%.

 

[EGT01]

kvbalu,

I would be a little cautious about arbitrarily applying any code, standard or guideline without making sure what your project requires or allows.

Here's an example of some of the different codes, standards, practices that may apply...

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=20046

Follow the link for 1910.110 at the top of the page in the above link and look at 1910.110(d)(4)(iii) which essentially is the same as NFPA 58.

There is a difference between what API RP-521 allows and what NFPA 58 allows.

API RP-521 does not say whether it is or is not specifically for LPG installations but API Standard 2510, Design and Construction of LPG Installations and API Publication 2510A both reference API RP-520 and API RP-521 for relief system design. However, API 2510 also says it is not for underground or mounded storage tanks.

API RP-521 suggests a 0.03 environmental factor for earth-covered storage and a 0 (zero) environmental factor for below-grade storage.

NFPA 58 does not distinguish between mounded or underground installations and they suggest an "equivalent" 0.3 environmental factor in either case. In that respect NFPA 58 would require a larger relief system than API RP-521.

Again, you need to look at your project requirements to determine what codes, standards or guidelines can be applied. The ones above would apply in the US but there could be others that you need to consider, for example, the Health and Safety Commission of Great Britain have some that I'm not familiar with their details...

http://www.hse.gov.uk/lau/lacs/52-14.htm

There could be other local requirements that you must also consider.

 

[joerd]

EEMUA also has some good references, such as their publication 190: [tt]Guide for the Design, Construction and Use of Mounded Horizontal Cylindrical Bulk Storage Vessels for Pressurised LPG at Ambient Temperatures [/tt]

Cheers,
Joerd

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