HID lights emit a good deal of heat. In confined spaces this heat can build up, resulting in unacceptable temperatures (greater than 85F). General venting alone may not provide enough air to maintain moderate temperatures.
This venting scheme is similar to general venting, but using a larger commercial grade blower. Its size is based not on the volume of the space but on the wattage of the lights.
Place the blower so air is drawn from the top of the space where the air is hottest and vented out. Size it by the required CFM (see application guide below). Blowers are rated by the amount of air they move in CFM (Cubic Feet per Minute). Bear in mind that with any duct attached, a blower will only move about 1/2 the rated CFM.
PHP Code:
Wattage of Lights Typical CFM Requirement
250...............................100
400...............................150
1000..............................350
.