Discussion in 'Indoor Growing' started by PicklesRus, Jan 8, 2017.
Not if I stack 539 lettuce plants with 3 315s stacked vertically in a coliseum.
I would like to see a picture of that!! i bet it fn boss looking...
ULTRAVIOLET RADIATION HAZARDS FROM GROW LAMPS
Aerobiological Engineering Report 10-15-15
Grow lamps are seeing increasing use in the expanding medical marijuana industry but growers may be unaware of
hazards from grow lamps due to low levels of ultraviolet radiation emitted from certain types of grow lamps. Two
of the most common types of grow lamps are Metal Halide (MH) lamps and High Pressure Sodium (HPS) lamps. In
general, lamps that generate UVC radiation (200-280 nm) include a glass outer shell or a blocking plate intended to
filter out the UVC light. Fluorescent lamps generate UVC internally but are coated with phosphors to absorb the UV
Little detailed information is being provided by manufacturers on the exact amount of UVA, UVB, and UVC
radiation emitted by their lamps. Anecdotal sources from the Internet have provided some information. For
example, one 315 W Ceramic Metal Halide (CMH) lamp is specified as producing 3.45 mW/cm2
of UVA, 0.01
of UVB, and 0.03 mW/cm2
of UVC. The latter irradiance value is equivalent to 0.3 W/m2
and according to
the NIOSH/ACGIH limits of exposure this would limit the time of exposure to 100 seconds. Obviously there is a
potential hazard for any lamp that emits this level of UVC radiation and growers need to be made aware of the
Another Internet source quotes the UVC output of a 1000W Metal Halide lamp as 0.02 mW/cm2
, which has an exposure time limit of about 180 seconds. Growers need to take precautions around grow
lamps and it is recommended that full-body coverage and protective glasses be worn in grow rooms when the
lights are on.
There is also a concern that some growers are removing the UV light blocking plates that are included
with some lamp fixtures. The removal of these glass or plastic plates can cause severe eye damage and skin burns.
According to one source that measured the UVC coming from an uncovered 70 W Metal Halide lamp, the levels
were 0.57 W/m2
at 8 inches distance, and 0.08 W/m2
at 24 inches distance from the lamp surface. The former time
exposure limit would be about 52 seconds while the latter would limit exposure to about 8 minutes. Clearly these
blocking plates should not be removed.
Fluorescent grow lamps can also present a UV hazard if the phospors contain a gap and UV radiation leaks
out. This is a hazard that has been noted by a number of groups for compact fluorescent lamps and one that poses
a skin cancer risk due to long term exposure.
I have personally measured UVC levels from two types of lamps, a Hortilux 1000 W grow lamp and a 100
W fluorescent grow lamp and detected no measurable UVC radiation. If anyone has actual measurements of the
UVC output of Metal Halide lamps, or manufacturer’s specifications on UVC output, please forward them to the
so i have been looking at CMH bulbs, wanting to know if they make one that will work in my existing 400w MH magnetic ballast.
The ballast is totally different. They are low frequent square wave units and they're the main reason why the 315W lights are more efficient.
UVC will fuck you AND your plants up.
Use UV supplemental lighting on a separate circuit so you can shut it off when working around the plants.
I've been saying this for awhile now. Macular degeneration is real and irreversible.
So the Philips are dipped in a filter type solution to reduce it. However; there's a dude out there can't find the link off hand but he makes a 315 without the UvA uvb coating. I've never ran it but I'll endever to find it and show you guys some of the field trials with it...
T5. A better way to go
So if these CMH bulbs can be used from seed to harvest and and 315 watts will cover a 4x4 tent? Why are they not used more? Its not like they are crazy expensive. What is the down side here?
You'll likely want two lamps to do that space justice. They're great for HID but LED is better, more efficient, longer lasting and getting more affordable all the time.
As an led man, I built a 180w at the wall fixture for less than a China led. I used cree 3070 and meanwell drivers.
Damn thing burned my plants at 14 inches. Next time I'm diy'ing with dimmers.
Post a pic. Would like to see your setup
super simple diy build.
im all about the easy cyberpunk/rat rod styling, so skeleton builds like this are both easy and imo good looking. something about zip ties also makes me happy.
I prefer a chunky, heavy duty industrial design language; four KB 80 degree glass lenses over CXB3590 3500K chips driven at 54W each, total of 225W at the wall with the driver. 2"x4"x 3/16" thick square section aluminum structural material. Water cooled.
uhuhuhuh, sooooo sexy.
i considered building a diy pc watercooled setup that would let me run single fan radiators between heat sinks. i will do it for fun, but again, im waiting to do it in the 5X5 tent build. when $$$ and skillz allow.
.very nice, you should put together something on water cooling. I am sure there would be a lot of interest in that.
Fun fact; I can run water through it at any temperature between freezing and 140F, or just fill it, cap it and it acts as its own heat sink given some airflow.
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