[FlowSyn]

Our lab has recently acquired a 200W med. press. Hg Ace-glass lamp/power supply to use for conducting photochemistry experiments.  The standard in the literature seems to be 450W and above.  It is my assumption that higher wattage lamps generally result in shorter conversion times providing all else remains constant.  The idea of leaving one of these lamps running for days doesn't seem like a great idea - especially without a power/safety cutoff switch.  Any comments from an experienced photochemist would be greatly appreciated. 

[discodermolide]

Our lab has recently acquired a 200W med. press. Hg Ace-glass lamp/power supply to use for conducting photochemistry experiments.  The standard in the literature seems to be 450W and above.  It is my assumption that higher wattage lamps generally result in shorter conversion times providing all else remains constant.  The idea of leaving one of these lamps running for days doesn't seem like a great idea - especially without a power/safety cutoff switch.  Any comments from an experienced photochemist would be greatly appreciated. 

You need to think about the quantum yield of the reaction/lamp. I see no problem with running it for days, you can always get a safety switch built in.

[zaphraud]

Our lab has recently acquired a 200W med. press. Hg Ace-glass lamp/power supply to use for conducting photochemistry experiments.  The standard in the literature seems to be 450W and above.  It is my assumption that higher wattage lamps generally result in shorter conversion times providing all else remains constant.  The idea of leaving one of these lamps running for days doesn't seem like a great idea - especially without a power/safety cutoff switch.  Any comments from an experienced photochemist would be greatly appreciated. 

Its just a "unfluorescent lamp" - a fluorescent with no phosphors to fluoresce, and nothing to stop the UV from getting out (fuzed silica/quartz enclosure) .. so why wouldn't you want to run it for days, weeks, or even months? That's a pretty well established technology, and the failure mode for these lamps is usually pretty mild, right?

If its well built, leaving it on shouldn't be any worse than leaving on any other lightbulb...