FISHER HAMILTON SAFEAIRE series, Installation Instructions Manual, Page: 28 / 32

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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.
SAFEAIRE
®
LABORATORY FUME HOODS
OPERATION, MAINTENANCE AND INSTALLATION INSTRUCTIONS
FIELD TESTING
NOTE: If not in accordance with specified face velocity, refer
to Troubleshooting section on Page 31, for aid in determining
the cause of variation in air flow. If face velocity can not be
corrected to that which is specified, reclassify fume hood to
conform to actual face velocity. Shut off auxiliary air when
testing an Auxiliary Air fume hood.
Sash Operation
Check operation of the sash by moving it through its full travel.
Sash operation shall be smooth and easy. Vertical rising
sashes shall hold at any height without creeping up or down.
AIR FLOW
Fume Hoods
Turn fume hood exhaust blower on. With sash in the open
position, check air flow into the fume hood using a cotton swab
dipped in titanium tetrachloride or other smoke source. A
complete traverse of the fume hood face should verify that air
flow is into the fume hood over the entire face area. A reverse
flow of air indicates unsafe fume hood operation. Consult the
Troubleshooting section on Page 31, for possible causes and
take corrective action. Move a lighted smoke bomb throughout
the fume hood work area directing smoke across the work
surface and against the side walls and baffle.Smoke should be
contained within the fume hood and be rapidly exhausted.
Low Air Flow Monitor
On fume hoods with low flow warning devices, verify that
monitor functions properly and indicates unsafe conditions.
FUME HOOD EVALUATION IN THE FIELD
It is recommended that the user make provisions to have the
following tests performed on all laboratory fume hoods. These
tests should be performed by qualified personnel to verify
proper operation of the fume hoods before they are put to use.
The tests of the fume hoods should be performed after the
installation is complete, the building ventilation system has been
balanced, and all connections made. Any unsafe conditions
disclosed by these tests should be corrected before using the
hood.
TEST PROCEDURES
Test Conditions
Verify that building make-up air system is in operation, the
doors and windows are in normal operating position, and that
all other hoods and exhaust devices are operating at designed
conditions.
Room Conditions
Check room condition in front of the fume hood using a thermal
anemometer and a smoke source to verify that the velocity of
cross drafts does not exceed 20% of the specified average
fume hood face velocity. Any cross drafts that exceed these
values shall be eliminated before proceeding with the fume
hood test.
Equipment List
(a) A properly calibrated hot-wire thermal anemometer similar
or equal to Alnor Model No. 8500.
(b) A supply of 1/2 minute smoke bombs.
(c) A bottle of titanium tetrachloride and a supply of cotton
swabs or other recognized device for producing smoke.
CAUTION
Titanium tetrachloride fumes are toxic and corrosive.
Use sparingly, avoid inhalation and exposure to body,
clothing and equipment.
NOTE: It must be recognized that no fume hood can operate
properly if excessive cross drafts are present.
Face Velocity
Determine specified average face velocity for the fume hood
being tested. Perform the following tests to determine if fume
hood face velocities conform to specifications. With the sash in
normal operating position, turn ON the exhaust blower. The face
velocity shall be determined by averaging the velocity of six
readings taken at the fume hood face. Readings shall be taken
at the centers of a grid made up of three sections of equal area
across the top half of the fume hood face and three sections of
equal area across the bottom half of the fume hood face.