All, We need to shut down one of the chemical exhaust fans for the EAST lab wing for this coming Thursday (3-22-07) from 5:30 AM to 8:30 AM. Something slipped on chemical fan EF 2B and belts are very loose. During this time we plan to complete the 6 month PM on the makeup air unit and the other exhaust fan. One chemical exhaust fan will remain running during the PM down time for safety. During the PM you will experience negative pressure in all the labs in the east lab wing making it difficult to open doors and possibly notice low exhaust alarms on the hoods. Lab staff will close all fume hood by sliding doors closed and posting do not use signs on the hoods during the PM time. Thank you, Mark