All advice so far seems relevant.
Is the other electrical equipment in the store rated for hazardous areas?
Ex approved etc.?
Does the store come under DSEAR zoning, if so which zone as the electrical equipment would need to meet the requirements of that zone.
NOT my area of specialism I don't do Ex equipment and systems designs and installs, yet, PI is TOO expensive at the mo!
However, I have had an overview, I have to for my business and we are moving that way to some extents.
Some zones will have maximum surface temperatures etc. for any installed equipment.
Are you sure the voltage is 100V a.c. as this is an oddball UK voltage.
Presuming here that you are UK based else all my stuff is out the window as I only look at UK work!
This is NOT a straight forward job, from a H&S standpoint, nor an engineering standpoint.
Wet heating may be the best option, what about a “plumbed in radiator”?
Chris’ lights is a good idea, tungsten lamps 10% light 90% heat, that’s why we all have to stop using them and loose all that spare heat in our homes that we will have to replace from the heating systems!!!
Also, why should the paint freeze?
Water freezes (begins) at 0 Celsius, add some other stuff and the freezing point drops lower. (salt etc loads on that at the mo!)
If the paint is solvent based as you suggest then the water content must be negligible as they are not miscible?
Water expands on freezing and is one of the few substances that does, hence the split pipes etc. they split when the water freezes but don’t leak till it thaws because the split is well sealed by the ice. Don’t I know it, I have a skating rink in my garage following a blown pipe coupling!
Most other materials shrink on freezing, polymers, metals, etc.
I would suggest the 1st place to start are your TDS & MSDS from the manuf’
Check acceptable storage temps there in.
IF the paint is water based is it actually flammable?
Think old gloss paint, oil based, clean the brushes in “turps”, flammable. Try freezing that, no chance, it thickens in cold weather same as other petroleum based substances, like diesel, hence the anti-waxing additives that are put into that for the cold weather, also, think of old automotive cellulose paints, extremely flammable.
Think new emulsion paint, water based, no flammability markings on the tin. Not sure about new automotive water based paints.
I just cant see how something that is perhaps a 50% water emulsion can burn?
It can’t technically be a solution can it as the colorants and pigments etc will not dissolve in water. Metal working cutting fluids are water/oil emulsions, the neat oil is flammable, the resultant mixture whist unpleasant in various ways will not burn (within reason).
Paul