PSA: UV box fire hazard

[Steve Voigt]

Yesterday morning, I went out to the shop to check some samples that were curing in my UV box (constructed a couple months ago). As I lifted off the lid, smoke started to stream out of one of the fixtures! I quickly unplugged and took the stuff outside, and it quit smoking after a couple minutes. 

I did some research and found that the supplier, Spirit Halloween, recalled their 48" black lights this summer because of fire reports. Mine were 18", which have not been recalled (yet), but it's reasonable to suspect they suffer the same defect.

I am pretty shaken about how close I was to losing my livelihood. The smoke started while I was holding the fixture--what if it had started in the middle of the night? I'd be f@*$ ed, that's what.

So, a safety overhaul is up next. I'm thinking of replacing the cheapo fluorescent black lights with LEDs. Reports are mixed, but several people here have reported good results curing varnish with LEDs in the 390-405 range. And from what I've read, the fire risk is much less. It also seems a good idea to make the box as fireproof as possible. Plywood lined with foil-faced rigid foam works great, but maybe it's not safe enough? I am not sure. The box should be plugged into a surge protector (it was not). And I'm long overdue to get a smoke detector that links to my phone, so I'll know if a fire starts overnight.

I would greatly appreciate any thoughts on fire safety of bulbs, UV boxes, and any related fire safety ideas that any of you might have. Thanks in advance.

[Michael_Molnar]

Did the UV box get too hot which contributed to the failure? I had a thermometer on mine and a vent fan to circulate air. IIRC it was 85 F.

You are one lucky fellow.

[Steve Voigt]

Hi Mike,

I don't think so. I kept a temp/RH meter in the box; winter temps didn't exceed low 60s (F°).

And yes, I am feeling pretty lucky.

[David Burgess]

Mine has a high-temperature cutoff switch which cuts the electricity if the temperature exceeds 90 F. I don't have a smoke cutoff switch though. Maybe I should, along with an automatic halon fire suppression system?

[duane88]

I have the ballast on the outside of the box and a smoke alarm placed adjacent to the ballast. 

[Steve Voigt]

2 hours ago, David Burgess said:

Mine has a high-temperature cutoff switch which cuts the electricity if the temperature exceeds 90 F.

 

2 hours ago, duane88 said:

I have the ballast on the outside of the box and a smoke alarm placed adjacent to the ballast. 

Excellent ideas. Thanks to both of you.