Abstract
Research facilities at the university where this program was developed currently occupy about 3200 laboratories containing 900 chemical laboratory hoods. A program of annual surveys of hood performance has been in place for 30 years. In addition to chemical laboratory hoods, university laboratories also contain more than 1300 specialty local exhaust ventilation (SLEV) systems for laboratory instrumentation, engineering pilot plant operations, semiconductor fabrication clean rooms, and physical plant shops. To comply with the Occupational Safety and Health Administration Laboratory Standard 1910.1450, which requires verification that engineering controls are performing adequately, we developed a program to monitor performance of SLEV systems. Program development included: (1) survey of all laboratory spaces and identification of SLEV systems; (2) classification of systems and uses; (3) evaluation of design criteria by comparison with existing American Conference of Governmental Industrial Hyggenists (ACGIH) criteria (where available) or development of new criteria; (4) selection of appropriate methods for performance evaluation; (5) performance measurement; (6) development of a computerized database to track performance; and (7) development of a reinspection program. Of the 1340 SLEV systems surveyed, 35.5 percent were complete enclosures such as chemical storage or gas cylinder cabinets; 8.5 percent were partial enclosures of operations such as machining operations; 15.3 percent were exterior slot hoods; 6.7 percent were exterior canopy hoods; 29.1 percent were drops or snorkel exhaust hoses; and the remaining 4.9 percent served miscellaneous operations. About 40 percent of these systems were not covered by existing ACGIH ventilation criteria. Several case studies of development of design criteria or measurement protocols for different systems are presented.