I am not well versed on this section of the code, especially the 20th edition. What would be the classification of a room with a 40, 000 litre tank storing # 2 fuel oil be? IE this is diesel, so I dont know if with the flash point of diesel, the area isnt a hazardous location.
It seems that a room with a diesel genset is not a hazardous location either, and you are pretty much certain fuel is being stored there.

#2 heating oil is not considered a volatile substance as its flash point is very high, 52 degrees C. Locations where it is stored is not considered a hazardous location for the requirements of sections 18 and 20 of the CEC.

Thanks Rick, are you referencing a rule on flash point? I checked sections 18 and 20 and also the appendix, and did not find diesel/#2 heaing oil mentioned, so I assume it is not part of those sections.

Hi Jay.
If section 18 applies to diesel, it would have to be a Class 1 location as per 18-004 (a)---"Class 1 locations are those in which flammable gases or vapours are or may be present in the air in quantities sufficient to produce explosive gas atmospheres"

So I guess the question is whether diesel produces flammable gases "in quantities sufficient to produce explosive gas atmospheres".

Looking at the table in appendix B (18-066), I see that diesel is not listed. However, looking at fuel oil #2 msds sheets (section 5), it would appear that diesel does indeed give off explosive vapours.

I would think that 18-006-(c)-(ii) would apply, as you have "flammable volatile liquids...normally confined within closed containers...can escape only as a result of accidental rupture or breakdown..."

Just my $0.02


Shawn.

Not technical.. well maybe. Mythe Busters, Did a show on a leaking gas tank catching up to a speeding away vehicle and blowing up. That didn't happen, The gas stayed up to speed at about 3 MPH.
Then the diesel test: Even slower and they had a difficult time even getting the vapors to ignite.

For what it's worth. (Just a lighter momment)

NFPA 497 - "Recommended Practice for the Classification of Flammable Liquids, Gases, or Vapors and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas". Defines a "Flammable Liquid" as one that has a flash point lower then 100 degF.

This means Diesel or #2 heating oils, with a flash point of 152 degF, is a "combustible liquid" and not a "flammable" one. And as such, CEC sections 18 & 20 clearly do not apply to a combustible liquid, only a flamable one.

Here is a link with some reading on the subject... While this is a link that is based on the NEC, the situation is the same.

http://www.mikeholt.com/codeforum/ultimatebb.php?ubb=get_topic;f=22;t=000043

Again thanks. You have to do a bit of digging for it, but it appears section 18 and 20 do refer to flammable liquids and combustible dusts, I dont see combustible liquids.