Zoning for Methanol 1

[Elec17]

I'm an electrical engineer and have been asked a question because I've had some involvement with explosive atmospheres (ie vapours and dusts possibly igniting because of a spark or other heat source). Somone is importing and storing about 12 by 5 litre (About 60 Litre total or about 16 US Gallons) plastic containers of methanol in a warehouse. Should warehouse be zoned as a potntially explosive atmosphere (probably Zone 2 in European terminology) I'd be interested in anyones thoughts.

 

[JLSeagull]

Is this pure methanol or a mixture (perhaps diluted with water), what is the percentage of the methanol in the mixture and what other significant components exist?

 

[moltenmetal]

Absolutely not. Storage of small quantities of properly stored flammable materials does not require a Div 2 area classification. Think about your hardware store- how many cans of lacquer thinner do they store in there at a time, much less in their warehouse?

 

[bchoate]

Elec17
I am going to give you basic information for methanol and you can decide what to do about methanol.
Methanol is extremely flammable and toxic. The flash point is 60.1 F (closed cup). The NFPA class is 1B flammable liquid. Explosive limits are 6% v/v in air (lower) and 36% v/v in air (upper). An ignitable or explosive mixture in air exists over methanol at temperatures of 60 F to 106 F. One needs to consider that an ignitable mixture in air exists in a small region over a spill. A large volume such as a warehouse will have several air exchanges and the methanol will disperse into non-ignitable mixtures.

The fire triangle requires the coincidence of fuel -- oxygen -- heat for ignition or explosion. Storage safety is based upon mitigating the potential for ignition sources.

More detailed information about good storage practices can be found at

http://www.methanol.org.

There is a good video and safety handbook for methanol usage. The Methanex corporate website has valuable information as well.

 

[unclesyd]

Check with your insurance and the local fire Marshall for local ordinances for storage of flammable liquids. You can run into situations where one or the other will require a special area or sprinklers etc. for such storage.
Our insurance require special rooms for such storage of any quantity of flammable liquids in any quantity than that deemed for everyday use,

 

[zaigrata]

Dear Elec17,

Your three considerations should be:
1. the bottles are tightly closed
2. kept at room temperature - kept away from heated equipment, etc.
3. the room is relatively well ventilated
there should be no worries - it's flammable, but not so dangerous if these basic safety measures are taken into consideration

 

[moltenmetal]

My hardware store happens to also have plenty of 1 litre and 4-litre plastic containers of methanol on its shelves, since it is used as a thinner for shellac amongst other things. They also have acetone, PVC glue and primer (MEK and THF), lacquer thinner (various aromatic and oxygenated solvents) and numerous other HIGHLY flammable materials- and all the same in spray cans as well.

Storage safety isn't just about mitigating ignition sources. That's the focus of the electrical codes because ignition is the only part of the triangle they have anything to do with.

If this is a filling or dispensing operation, that's a very different story!

If this is simply storage, a flame-resistant cabinet bonded and vented in accordance with the manufacturers' instructions will provide sufficient protection in most jurisdictions. That also presumes typical low-firespread construction (i.e. this is not an old wooden buildng), and the normal protections against fire are also in place (sprinklers, smoke/fire detection and alarming etc.). Div 2 electrical area classification for these circumstances would be equivalent to swatting a fly with a sledgehammer.

 

[MJCronin]

To all,

Warehouses have thier own classification system for storing combustable and flammable liquids.

NFPA and the insurance companies know all about this.

It's all a question of quantity and fire protection systems.

I think that you want OSHA rules: "Flammable and combustible liquids. - 1910.106 "

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_id=9752&p_table=STANDARDS

Just my opinion....

-MJC

 

[Elec17]

Cheers all. yea my feeling was that ex fitting would be overkill in the situation in question.