Flammable Vapour Cloud Distance

[jdhariwal]

Hey All,

I would appreciate anyones help on this matter:

I have a release from a vessel of propane gas

How can I find the distance to the LFL / UFL from the source?

Are there any good calculations available (worked examples)?

Any help would be apprecaited on this matter

Kind Regards

J

[safetyuser]

Hey All,

I would appreciate anyones help on this matter:

I have a release from a vessel of propane gas

How can I find the distance to the LFL / UFL from the source?

Are there any good calculations available (worked examples)?

Any help would be apprecaited on this matter

Kind Regards

J

This is a "consequence analysis" for a leak and dispersion scenario. Your problem has 2 subsequent steps for its solution:
1- a theoretical model for the release of flashing propane
2- a theoretical model for the dispersion of propane vapour in air

For newbies to consequence analysis I would recommend to be supported by a software tool, there a lot on the market
but if your are fond of mathematics and analytic solutions you could try with the evergreen

CCPS "Guidelines for consequence analysis of chemical releases"
and in the book there are a number of worked examples to start

You can find somewhere in the forum

hope this helps

[jumbodumbo]

You can use ALOHA. This is a part of the CAEO group of software used for emergency planning. ALOHA has been developed by US EPA. It is free and downloaded from

[link Point to another website Only the registered members can access]

[gateaux_boy]

Thx.

[NandoEs]

There are various standards, but all are for clasificaion of area, and gives recommendations relating to electrical equipment associated with the people could not tell which are the rules that govern.
API-RP-500 - 1997/1998 “Recommended Practice for Classification of Locations for Electrical Installations at Petroleum Facilities Classified as Class 1, Division 1 and Division 2.”
ANSI/ISA – TR12.24.01 1998, (IEC –79-10) “Recommended Practice for Classification of Locations for Electrical Installations Classified as Class 1, Zone 0, Zone 1 or Zone 2.”
NFPA-30 - 1996 edition “Flamable and Combustible Liquids Code.”
NFPA-70 - 2002 edition “National Electrical Code.” NEC
NFPA –496 -1998 “Purged Pressurized Enclosures for Electrical Equipment
NFPA –497 - 1997 “Recommended Practice for the Classification of Flammable Liquids