What is deemed an explosive location?

[Dave A]

class I – dusts that ignite and propagate flame readily;

Well, that's where flour gets interesting. Ordinarily it wouldn't qualify - you have to get a pretty specific air/dust mix before the magic happens.

The risk areas will generally be where it's being milled or moved and you end up with a suspension of fine flour in the air.

As it turned out in this instance, the flour is stored in bags in the storeroom (so we're not in a silo situation) and the only area where flour is poured dry is into the dough maker - and that certainly isn't producing the type of flour saturated atmosphere that would be cause for concern.

Now if we were talking gunpowder, different story.

[murdock]

as an installation electrician you are not required to know about regulations like a master elctrician...different spray booths spray booths would have diffrent areas classified...

as an example a closed spray booth with extraction sufficient to move the air at a certain quantity with safety valves on equipment etc would be different to a spray booth which is not entirely sealed...

some spray booths have flame proof fitting and othere have sealed glass and an outside cabinet which houses the fitting so the fitting is not always required to be a flame proof one....the motor for the extrctor fan might not be mounted inside the exhaust...so there is nothing stopping you as an installtion electrician signing off the installtion...you get the idea


my point is you need to understand the application and have the area classified by a certified person...which would not be your responsibilty.

my rule of thuimb is if you can smell it or see a haze or see signs indicating no smoking zones then beware.

if you are not a master electrician and you see a db which you need an allen key to remove the cover which has 30 bolts in it becareful...or long glnds which make the installtion just look like it was over speced becareful...

i would be interested to know what would happen in a case like this because much like a plumber connecting a geyser who doesnt have the correct qualification...he doesnt know any better...what if someone is hurt...

most people dont know the dangers of dust...nor do they know the dangers of the kitchen cupboard with all the different chemicals...so back to the customer if he runs a plant he should know the status and classifications of various areas.

something else i have just thought of is what happens if the paint is non flamable like a factory i worked in a little while ago...the spray booth is harmless because all the paints are water based...so back to the custmer again...how are you suppose to know...

i had another situation a while back where all standard fittings...plugs DBs etc where installed then along came the new tenant...he was using highly flamable solvents exposed...its not the electrician who did the installtions fault that nothing was rated...how was he suppose to know what they wer going to use the factory for...back to the customer or tenant in that case...we cant be held responsible for the negligence of other people.

i never put any specific specs because i am not aware of the application as a whole...something else i learnt from a very wise man

[Master Electrician]

Hi Dave,
Having worked in the milling and baking industry, I hope the following pointers will help.
Establish what is on the premises. Sectionalise it.
Flammable store. (Oil, paint, etc.) Hazardous Area
Fuel dispensing. Hazardous Area
Bulk offloading of flour from a tanker to a silo. Hazardous Area.
Bag store. Hazardous Area. In this case, all fittings need to be dust ignition proof.
A bakery is unlikely to generate sufficient quantities of dust to produce an explosive atmosphere.
However, be aware that the ovens operate at high temperatures.
Cables and equipment need to cope with this.
Adequate ventilation is required.
My 2c

[garthu]

At home......

When you have asked your wife sarcastically if the vacuum cleaner is working or not?