Enclosing my 400w MH with no ventilation - possible? or bad idea

I have a 400w MH that I really dont like using cause the bulb can break and cause a fire. I dont know the history of this rig, but it looks kinda beat to me, so I dont wanna risk fire etc.

Anyways, my solution (i think) is to set the hood on glass thats being held up by an upsidedown table, so if the bulb does bust, itll land on the glass. My only problem with this is that there will be no airflow through the hood. Is this a problem? Or is this perfectly alright

You shouldn't really use an HID lamp in an enclosed space, for a start the heat build up would drastically shorten bulb life, not to mention creating a potential fire hazard. Is there no way of ventilating the space? Just leaving a gap round the edge with a small desk fan to circulate the air would be much better.

some kinds of glass will shatter w/too much temp difference in each side, I think maybe

When in dought, vent. Heat is your enemy in a grow room, whether it is near your plants or your equipment. Only with CO2 infusion would you need to conisder limiting the air flow through your grow room.

alrighty. Looks like ill be cutting holes in the hood. Its an old POS anyway, looks like its been handed down since the 80s or some shit. Ima place it on the glass, and put large holes in the sides and make sure my rotating fan is hitting it.

Thanks

I use a 400w with glass and no air blowing through it, but I have a fan blowing directly on the hood all the time. I do have vetilation in the room and keep temps around 80.