I understand that linear tungsten halogen bulbs emit noticeably more UV light than general household incandescent bulbs.
Would it be safe to use a 300 Watt tunsten halogen floodlight as a good bright light in my home office?
This would be on for approx 8 hours a day. I'm wondering that maybe after that sort of exposure the extra UV could become a significant adverse effect on eyes & skin.
It's generally inadvisable to use these indoors because of fire risk.
They are not suitable.
Use high frequency tri phosphor tubes. They have the additional advantage of not using an obscene quantity of carbon dioxide emmisions for the same output.
Christian.
If there is no glass between you and the bulb then it would definitely be hazardous - this is why dichroic bulbs for table lamps have a cover glass on the front. I don't know if glass attenuates UV sufficiently to be safe for long-term exposure. For office lighting, you really don't want a single-point source, as it casts shadows too much - you would want to at least uplight it onto a white ceiling.
Fluorescents would probably be much better.
To answer your question -- yes, tungsten halogen lamps do emit substantial amounts of UV and they are perfectly capable of causing skin and eye damage if you are directly exposed to the light of an unshielded lamp. In Italy some years ago, users of small halogen task lamps reported sunburn and other UV-related problems because the lamps were not shielded.
But a piece of glass will filter the UV to minimum levels and the halogen lamps should be enclosed anyway in case of bulb rupture. You definitely don't want to experience that in a home office situation.
As others have said, however, there are much better, more efficient and safer ways to light your office using fluorescent lamps.
Terry McGowan
I agree with this. To withstand the high temperature, the envelope is made from fused silica.
In addition, if you can get it, nonex glass (trade marked by Corning) is a borosilicate glass that is ostensibly transparent but very good at blocking soft UV. There probably are similar competitive products.
Bill
-- Ferme le Bush
We had the same issue in the UK.
They can also cause polycarbonate damage if the polycarbonate is directly exposed to the light of an unshielded lamp.
DS (Yes, I'm kvetching about poor US headlamp specs again)
I had a 500 watt halogen linear fail after being dropped.
I was working on a pint job and moved the lamp to an unstable position. It fell, and continued working. I thought: these are quite sturdy, and put it in a more stable position and continued working. After that, a pretty loud bang and the house fuse blowing.
The tube had blown a hole and spewed out it's length of filament, which was quite long - it could have hit me if I was working nearby. But with the fuse blowing, at least I wouldn't have been electrocuted, I suppose.
Thomas
Would any glass hold back a reasonable amount of UV?
I would guess that the glass used in many of the cheap doemestic floodlights is probably not all that specialised..
Bitter? (sorry).
In message , JS writes
Yes. Common glass blocks UV. The problem with UV emission from some lamps is because they are made of quartz which doesn't generally block UV.
Some modern lamps have UV filtration incorporated.
Surely any lamp fitting which uses one of the linear quartz-halogen bulbs is *required* to have some sort of shield. Certainly all the ones I have used have a shield (glass in every case I've seen) and the instructions have warnings to say that if the shield is broken it must be replaced with something offering equivalent protection.
This would have protected that poster who was having a pint when the lamp exploded too! :-)
Underwriters Laboratory requires some sort of sheilding, although in some cases it is wire mesh rather than glass. (In case of "Non-passive Failure" - my favorite techno term, thanks to GE.) This covers 99% of North American instalations and equipment.
This UV scare has been going on for well over ten years. There was an experiment in Italy where they baked some hairless mice with unsheilded lamps. Gee, they developed skin problems. The press went wild....
***You get more UV walking to your car than from sitting under halogen lamps.***Note to JS: As you noticed lighting is not cut and dried, there are many options and the best solution depends on the details of your situation. Energy, quality, dimming, start-up, first costs, space, style, your age!, type of work....
Good Luck
The majority of high power fittings I've seen here (uk) had no shield of any kind. By high power I mean 500w and 1kW lamps. This includes indoor and outdoor fittings. Little 50 watters are different, with the majority having a glass shield.
NT
Chryslers, Fords, Mazdas, Subarus, Nissans, Volvos...
The DOT wrote the inferior testing standard that lets them degrade this way.
We had a case here in Oregon a year or two ago. Seems a large group of teachers was holding an institute day in the school gym under the metal halide lamps. Unknown to everyone who attended, one of the UV shields was broken and the teachers were exposed to high levels of UV exposure all day. Apparently there was a safety feature that was supposed to estinguish the light if the shield failed, but the safety feature failed instead.
At the end of the day, there were complaints of retinal burns, sunburn, severe headachces and a general sickness from just about all who attended. Lawsuits were threatened and it became a very expensive medical incident for the school district.
Prior to this, there was a general ignorance about the importance of mantaining the lamps in good repair. This event prompted a statewide review for the procedures in maintaining UV producing lamps, mainly that they need to be inspected periodically and if the shield is cracked or missing, the lamp should be removed from service.
Beachcomber
They are probably not easily-obtainable through lighting retailers. However, just go into a local hardware or glass shop and have them cut you a piece of glass to fit. Ordinary window glass is a fine UV filter. Use a thicker piece and even tempered glass if you want extra safety.
Terry McGowan
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