SAFEAIRE
®
LABORATORY FUME HOODS
OPERATION, MAINTENANCE AND INSTALLATION INSTRUCTIONS
FUME HOOD TESTING
29
Dimensions are nominal and illustrations and specifications are based
on the latest product information available at the time of publication.
The right is reserved to make changes at any time without notice.
The test sheet attached to the hood reflects hood performance
parameters. This sheet represents “AM” testing.
Fisher Hamilton strongly recommends that the ASHRAE 110-
1995 test procedure be subjected to this hood under “AU” (as
used) conditions.
Refer to the ASHRAE Standard 110-1995 or contact Fisher
Hamilton for further information.
If, for some reason, the above test cannot be performed at
the job site, Fisher Hamilton strongly suggests use of the
SEFA-1.2 1996 test procedure as minimal proof of proper hood
performance.
This test consists of a face velocity grid test and a smoke test
procedure.
Information and copies of this procedure are available from
Fisher Hamilton.
Fisher Hamilton also recommends at least semi-annual
verification that this above criteria is subjected to and met by all
hoods at your particular facility.
FUME HOOD TESTING
ANSI/ASHRAE 110-1995
The performance of a laboratory fume hood in providing
protection for the worker at the face of the hood is strongly
influenced by the laboratory room ventilation, and by other
features of the laboratory in which it is installed. Therefore,
there arises a need for a performance test which can be used
to establish an “as manufactured” and an “as used”
performance rating, including the influences of the laboratory
arrangement and it’s ventilating system.
The test presumes a conditioned environment. No test can
be devised which would, conducted once or infrequently, (viz.,
annually), reflect the results which would be obtained in a
non-conditioned laboratory with various conditions of
windows, wind velocity, etc.
This procedure is a performance test method.
It remains for the user, the hygienist, or the applications
engineer to specify what level of hood performance is desired
or required. It should be noted that the performance test does
not give a direct correlation between testing with a tracer gas
and operator exposures. Many factors, such as the physical
properties of the material, the rate and mode of evolution, the
amount of time the worker spends at the face of the hood, and
several other factors must be integrated, by a trained observer,
into a complete evaluation of worker exposure. The
performance test does, however, give a relative and quantitative
determination of the efficiency of hood capture under a set of
strict, although arbitrary, conditions. The same test can be
used to evaluate hoods in the manufacturer’s facilities under
(presumable) ideal conditions, or under some specified
condition of room air supply.
The test may be used as part of a specification once the
appropriate release rate and required control level are
determines. If so used, an “AM” (as manufactured) specification
places a responsibility on the hood manufacturer, and an “AU”
(as used) specification places responsibilities on others, viz.,
the designer of the room air supply, the designer of the room
layout, etc.
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