This is a shot inside the lamp compartment with the lens removed. It's a little crusty looking inside. The lamp is a Westinghouse 175 watt deluxe white lifeguard cleartop lamp made in April of 1972. It only has a little bit of whitening on the ends of the arc tube.
You found out the date eh? I know that those fixtures were actually made as late as the early 80s and was offered in HPS according to Rick Delair who told me this when I was asking him if he had one of those fixtures or know where to get one.
I found the date. Initially I couldn't get the lens off due to a seized screw, so I could see the top of the lamp, but couldn't see the date code. Once I got the lens off, I was able to read it.
It would be interesting to see one in HPS. I bet the lens would be in much better shape. I typically see MV/MH Hubbell wall packs with badly yellowed lenses, while the HPS ones aren't very yellowed at all.
You wouldn't happen to know what wattages these were available in?
I know they were only 100 and 175 watt in MV, not 250 that is for sure! for HPS I have NEVER seen ones that were HPS in the first place, and I believe the ones in NYC got retrofitted....unless it is possible they were HPS first place, but the lens ARE yellowed. I do have picture of those somewhere.
HPS does still yellow polycarbonate over time. Especially in a small optical space like this. Did these coem in glass or acrylic lenses? It seems glass and polycarbonate were the only two options way back when...
it takes a LOT longer for HPS yellow the polycarbonate.....I have a 1986 50 watt HPS wall/ceiling pack that is kinda yellowed but not as bad as it would be in MV....where I live, the posttops....i notice MV ones has slightly more yellowed panels than the HPS ones.
And for the fixture above...ALL of the ones I have seen myself in person were plastic in matter of fact!
I haven't seen many of these, and the only ones I have seen either had a badly yellowed/browned polycarbonate lens, or the lens was missing.
The yellowing is caused by heat. The heat can either be convective heat from the lamp, radiative heat from the lamp, or UV from the lamp, which is converted to heat when it strikes the plastic. UV from HPS lamps isn't much of an issue, since they emit very little, if any, and most of that would be blocked by the glass bulb. MV/MH on the otherhand, generate lots of UV, and though most is blocked by the bulb or absorbed by the phosphor (if any), UV does still escape and effect the plastic. Also, since MV/MH lamps tend to use larger bulbs, such as BT/ED28, the heat from the bulb is much closer to the lens than with an ED23.5 or T-type HPS lamp.
I saw a 100 watt version in Illinois and it had partly broken refractor it showed a fully coated BT-25 lamp! The place had 2 of them...the other was fully intact...
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It would be interesting to see one in HPS. I bet the lens would be in much better shape. I typically see MV/MH Hubbell wall packs with badly yellowed lenses, while the HPS ones aren't very yellowed at all.
You wouldn't happen to know what wattages these were available in?
And for the fixture above...ALL of the ones I have seen myself in person were plastic in matter of fact!
The yellowing is caused by heat. The heat can either be convective heat from the lamp, radiative heat from the lamp, or UV from the lamp, which is converted to heat when it strikes the plastic. UV from HPS lamps isn't much of an issue, since they emit very little, if any, and most of that would be blocked by the glass bulb. MV/MH on the otherhand, generate lots of UV, and though most is blocked by the bulb or absorbed by the phosphor (if any), UV does still escape and effect the plastic. Also, since MV/MH lamps tend to use larger bulbs, such as BT/ED28, the heat from the bulb is much closer to the lens than with an ED23.5 or T-type HPS lamp.
I saw a 100 watt version in Illinois and it had partly broken refractor it showed a fully coated BT-25 lamp! The place had 2 of them...the other was fully intact...