If your metal halide,and mercury lights have a glass outer bulb-UV is not a problem.Now if the outer glass bulb is broken and the arc tube is still running-then the short wave UV is a problem.Just about any maker of metal halide and mercury bulb make "fail safe" versions-that if the outer glass bulb breaks,or is punctured-the arc tube will go out.You can run your bulbs if you are present-as long as the outer glass envelope is intact the bulbs are completely safe for people and plants.a lens-glass-is good between the bulbs and the plants or whatever you are lighting is an excellent precaution.Protection from hot glass or quartz particles if a mercury or metal halide arc tube ruptures and bursts the outer bulb.On very rare occasions this can happen-usually from bulbs that are really old.That would be if the bulb has weak or very off color light output-and the arc tube looks very blackened when the bulb is off.Those should be replaced.And run the bulb in the position as stated on the package or the glass envelope.Some HID bulbs are position sensitive.Yes,with open fixtures-no lens or other barrier-a broken outer bulb can make the mercury or halide bulb a "sunlamp" and a powerful one.Can damage eyes,too.Sounds like your grow light fixture must have dual ballasts one for sodium bulbs and the other for metal halide.A switch or some other means selects the proper ballast for the bulb you want to use.Digital electronic ballasts select automatically!Just put in the bulb,turn the light on and the ballast "self adjusts" to the bulb.
Another obscure laundry model memory
- Thread starter arbilab
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Oh yes-digital ballasts are very lightweight,and have heat sinks or even a tiny fan in them.They usually run very cool for the bulb wattage.And they do not hum or buzz.You may hear a whining noise as the bulb heats up.
But for grow lights, you have to have the full spectrum of light including UV. I never looked at it if it was on and if I had to enter the plant room, I turned my back if I was near it. There were all kinds of warnings that came with the light. One bulb was for foliage and one for blooms. I think it was the one for blooms that put out the really dangerous rays. I don't raise the flowers anymore so I mostly get by with fluorescent tubes. They use less juice anyway.
Grow lights do not generate the harmful UV rays-they are filtered out by the outer glass bulb and if the fixture has a lens or diffuser-an additional filter.Plants do not need SW UV(the harmful rays)to grow.Most of the photosynthsesis in plants comes from standard visible light spectrum.SW UV are not visible to people.some insects,birds can see the rays.You can work in complete safety under your Halide or sodium grow lamps.the warnings on the bulb packages refer to bulbs that are broken or punctured.The "grow lamps" sold by most garden suppliers are enhanced commercial soduim or halide bulbs.the grow light sodiums have more blue spectrum than standard sodium bulbs and the halides have more red spectrum.Standard bulbs of both types are used too.I have used halide and sodium bulbs for lighting and have had no problems.no sunburn or blindness.I have a large collection of halide and sodium fixture that were surplused by electrical contractors in my area.They sell the old fixtures when the install new ones for a client.Most I have are very nice-I wouldn't have replaced them.The contractor even asked if I was going to use the lights for growing-many are used by tobacco plant growers to start tobacco seedlings before planting in the feild.
arbilab
Well-known member
Tobacco eh? Wink wink. (JK)
Yes,Tobacco-the stuff folks smoke in cigarettes and such.The market for it here is less than before.there used to be a plastic glazed greenhouse in my neighborhood here-the plastic is long blown off the roof and you just see the end walls and roof support hoops.Weeds now grow in the former "greenhouse."the tobacco crop here isn't what it used to be.the tobbacco is auctioned from the growers to the cigarette companies in Richmond.That greenhouse used to be lit at night with grow lamps-years ago.It was used to grow the tobacco seedlings.
Ozone bulbs in dryers.
The ozone bulbs that were used in dryers are arc lamps. They have a filament only to warm and vaporize the mercury so the arc will start.
The ozone bulbs that were used in dryers are arc lamps. They have a filament only to warm and vaporize the mercury so the arc will start.
arbilab
Well-known member
Saw a docu on tobacco once. Two actually. One on growing, and (shudder) one on what they do to it in the factory. I only started cigarettes in the first place to have something legal to smoke in public. Now I'm stuck with them, they've septupled in price, and they're only legal out in the alley with the winos.
I don't use tobacco in any form-just live in an area where most of it is grown.Its a long established industry in this area.And yes the crop is now currently being grown.the old style ozone bulbs used the filament for starting as and as one of the electrodes.The bulb is quartz so it will pass the SW UV radiation.Its not really an ozone bulb-but the reaction of SW UV to the oxygen in the air turns some of the oxygen to ozone.You will get this with any SW UV lamp.
