Adequate Face Velocity for Laboratory Hoods

Multiple organizations have adopted laboratory hood safety standards to determine the effectiveness of a hood in limiting occupational exposure.  One such measure of determining the effectiveness of the hood is by measuring the speed of air entering the hood (i.e. the face velocity).  While face velocity is not the only test method for determining if a hood has the ability to adequately contain the contaminants (see ANSI/ASHRAE 110-1995 Method of Testing Performance of Laboratory Fume Hoods), it is the only performance standard cited by the following organizations.

  • OSHA – General air flow should not be turbulent and should be relatively uniform throughout the laboratory, with no high velocity or static areas (194, 195); airflow into and within the hood should not be excessively turbulent (200); hood face velocity should be adequate (typically 60-100 lfm)
  • NIOSH – The current consensus of the literature is that the average face velocity for a laboratory chemical hood should be in the range of 80–120 ft/min
  • Cal OSHA – The exhaust system shall provide an average face velocity of at least 100 feet per minute with a minimum of 70 fpm at any point, except where more stringent special requirements are prescribed
  • ANSI/AIHA Z9.5-2003 – Design face velocities for laboratory chemical hoods in the range of 80-100 fpm (0.41-0.51m/s) will provide adequate face velocity for a majority of chemical hoods. Hoods with excellent containment characteristics may operate adequately below 80 fpm (0.41 m/s) while others may require higher face velocities. (more…)

ACGIH and AIHA Continue Alliance Discussions for OELs

The American Conference of Governmental Industrial Hygienists (ACGIH) and the American Industrial Hygiene Association (AIHA) announced that they continue dialogue regarding the proposed strategic alliance announced in May 2009 to develop occupational exposure guidelines. With the originally proposed alliance, AIHA would be an industrial hygiene member professional organization, and ACGIH would be a non-member scientific organization. This would most effectively leverage our efforts and resources to protect worker health, while ensuring that all professionals have an opportunity to be involved in supporting and developing the science and practice of industrial hygiene.

Late last year, ACGIH introduced an alternative alliance approach in which ACGIH receives funding from each of several professional occupational health and safety associations whose members have an interest and stake in the development and use of occupational exposure guidelines. More recently AIHA participated in ACGIH®’s direct discussions with key professional associations to gauge interest. These discussions are expected to continue over the next few months.

Source: Thomasnet, AIHA, ACGIH