Human-as-Mannequin Fume Hood Testing: Sample Protocol & Initial Results

Geoffrey C. Bell, Lawrence Berkeley National Laboratory
Tom Smith, Exposure Control Technologies, Inc.

ASHRAE's 110-1995 containment testing method uses a mannequin to simulate the presence of an operator at the fume hood. A detection instrument is located in the "breathing zone" of the mannequin. A test agent (tracer gas; usually sulfur-hexafluoride, SF6) is introduced inside the hood and the amount of "contaminant" that escapes the hood's sash opening, or face, is measured. This test is not performed using a human operator conducting experiments inside the hood.

So-called "Human-as-Mannequin (HAM) Dynamic Tests" are intended to be practical, dynamic challenges by simulating actual operator hand and arm movements through manipulation of objects within a fume hood that may cause loss of containment. These tests, or challenges, account for the combined ability of the hood to contain, capture internally, and remove contaminants. Tracer gas concentrations are measured at a technician's breathing zone and averaged over the test period.

A sample HAM test protocol is provided with results from a dynamic, HAM-test series. The protocol was compiled from information and points-of-view from numerous sources including: Tom Smith at Exposure Control Technologies, Inc.; Dale Hitchings at SafeLab Corporation; Mike Ratcliff at RWDI, Debbie Decker, et al, at University of California Industrial Hygienists; Geoffrey Bell and Dale Sartor with LBNL's Applications Team.

Labs21 Connection:

HAM testing is not presented in the ASHRAE 110-1995 Method or the ANSI Z9.5-2003 Ventilation Standard. There are no industry standards for Human-as-Mannequin (HAM) dynamic challenges, and no recommended threshold values for pass and fail. Therefore, thresholds may be established by testing hoods in a facility.

The Labs21 community and LEED™ accreditation can be bolstered by confirming that a fume hood is operating "safely" under actual, "as-used" conditions. LBNL researchers worked with California's Occupational Safety and Health Administration (Cal/OSHA) staff to devise an innovative HAM test protocol to evaluate hood containment performance via a "tracer gas" measured in a user's breathing zone while performing choreographed work sequence within the hood.

Biographies:

Geoffrey Bell is an Energy Engineer in the Environmental Energy Technology Division at Lawrence Berkeley National Laboratory (LBNL). He is credited with a number of publications, including serving as a principal author of the Design Guide for Energy Efficient Laboratories. This publication is intended to assist facility owners, architects, engineers, designers, facility managers, and utility energy-management specialists in identifying and applying advanced energy-efficiency features in laboratory-type environments. Mr. Bell is a Certified State Energy Auditor in New Mexico and a Registered Professional Engineer in both New Mexico and California. He has served as an investigator for the U.S. Department of Energy, a teacher at the University of New Mexico, and an energy engineer contractor to Sandia Corporation in addition to various other mechanical engineering consulting positions. Mr. Bell received his B.S. in Mechanical Engineering from Newark College of Engineering and a masters of architecture in Environmental Design from the University of Mexico.

Thomas C. Smith is the President of Exposure Control Technologies, Inc. Mr. Smith specializes in helping facilities achieve safe, dependable and energy efficient operation of laboratory ventilation systems. He holds a BS degree in Mechanical Engineering from North Carolina State University and a MS degree in Environmental Engineering from the University of North Carolina. Since 1985, Mr. Smith has participated in hundreds of laboratory ventilation projects and evaluated thousands of laboratory hood systems. He is a member of technical standards committees for ANSI/ASHRAE 110, ANSI/AIHA Z9.5, and ASHRAE TC9.10 and serves as a technical consultant to numerous companies, universities, and government agencies.

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