NuAire LabGard D NU-543-400, Manual

Page: 50 / 70

OM0283 Page 50 of 70
Rev 2 July/2021
7.7 Airflow Smoke Pattern Test
The airflow smoke pattern test is performed using a smoke source (i.e. smoke tubes) in and around the cabinet workzone
and access opening to determine a visual representation of the cabinet’s containment performance. To perform the test,
the smoke source should be passed through the following areas:
A smoke source shall be passed:
1. From one end of the cabinet to the other, along the center line of the work surface, at a height of 4 inches
(102mm) above the top of the access opening.
2. From one end of the cabinet to the other, 1 inch (25mm) just inside the view screen, at a height 6 inches
(152mm) above the top of the access opening.
3. Along the edges of the entire perimeter of the work opening approximately 1.5 inches (38mm) outside the
cabinet, with particular attention paid to corners and vertical edges.
4. 2 inches (51mm) from the sides up inside of the window at the side channel seals, and along inside of the
cabinet along the top of the work area or immediately below the wiper gasket.
The criteria used to evaluate the smoke patterns is the following:
1. The smoke inside the cabinet shall show smooth downward flow with no dead spots or reflux.
2. No smoke shall escape from inside the cabinet.
3. No smoke refluxes out of the cabinet once drawn in, nor does smoke billow over the worksurface or penetrate
onto it.
4. No smoke shall escape from the cabinet.
7.8 Site Installation Assessment Tests
These tests are performed to verify the sash position, airflow or pressure setpoint where an audible and/or visual alarm will
activate to signify unfavorable operating conditions within the Biosafety cabinet and/or the remote exhaust blower, and
canopy connection performance.
7.8.1 Sash Alarm
Step 1: With sash alarm switch enabled, raise the sliding sash 1” (2.5cm) above the manufacturer’s
designated sash height for normal operation. Verify that the audible/visual alarm activates/sounds.
Step 2: Return the sash to its normal operating height.
7.8.2 Airflow or Pressure Alarm (when installed)
Step 1: Measure and record the speed control operating voltage at the speed control test points using a
voltmeter.
Step 2: Using the primary or secondary inflow test method, lower the speed control voltage to reduce the
inflow by 20% from the certified testing value.
Step 3: Verify that the alarm activates when the inflow is dropped to this point.
Step 4: Adjust alarm setpoint as necessary as instructed by the alarm manufacturer procedures.
Step 5: Return the speed control to its certified operating voltage as measured by the voltmeter.
7.8.3 Exhaust System Performance
Canopy Exhaust Transitions
Step 1: Introduce a visible medium source into the canopy air intake(s) while slowly reducing the exhaust
volume until there is a loss of capture of the visible medium into the canopy air intake(s).
The audible and visual canopy alarms shall respond within 15 seconds, and the cabinet fan(s) will
continue to operate.
Step 2: Return exhaust volume to original value.
NOTE: Positive pressure ductwork conditions are strongly discouraged. Positive pressure ductwork conditions
should be reviewed and evaluated by a cognizant Safety Officer of Industrial Hygienist as part of their
Laboratory Ventilation Management Program and Chemical Hygiene Plan.
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