safe operating temp for 1000w HPS bulb?

Hi all,

If I'm pulling air from outside to cool my cooltubed 1000w HPS, and it's getting mighty cold outside, how cold until it isn't safe? Will the bulb shatter if the intake air is below 0? Below 10?

Thanks!

Really cold air is just fine - it's thermal shock (extremely rapid cooling - like throwing water on it) that shatters bulbs. There is nearly always enough mixing air that any temp change is comparatively slow when dealing with air. You generally don't see street lights blow out when it gets really cold, right?
keep on growin!