Ventilation rates of the labs are determined with respect to number of people occupying the lab and type of research conducted. This is done as a measure of energy conservation. Lab users should notify LS and LSS if a new researcher comes to lab and function of the room changes, so that LS and LSS will check the ventilation rate.
A properly operating fume hood creates negative pressure in the lab. It removes more air from the room than is being supplied. On the contrary, a positive pressure is where more air being supplied to the room than is being removed. When this takes place, dirty air in the laboratory, which includes chemical vapor and dust, is blown outside of the lab into the halls. This can result in chemical odors permeating the hallways and surrounding rooms and may also negatively effect fume hood performance. Lab users should routinely check the air pressure of the lab and compare it to the hallway.
Laboratory users can perform a quick check of the air pressure in their labs by using modified version of the dry ice test procedure (see Appendix 4.1). If you discover your lab to be under positive air pressure, then please contact LSS for assistance.