PerkinElmer aanalyst 200 User Manual page 57

Additional recommendations on the venting system include the following items:
•
Make sure the duct casing is installed using fireproof construction. Route ducts away from
sprinkler heads.
•
The duct casing and venting system should be made of materials suitable for temperatures
greater than 70 °C (158 °F). They should be installed to meet local building code
requirements.
•
The exhaust hood opening should be about 170 mm (6.7 inches) above the top of the burner
shield.
•
Locate the discharge outlet as close to the blower as possible. All joints on the discharge
side should be airtight, especially if toxic vapors are being vented.
•
Equip the blower with a pilot light located near the instrument to indicate to the operator
when the blower is on.
•
Equip the outlet end of the system with a back draft damper and take the necessary
precautions to keep the exhaust outlet away from open windows or inlet vents. In addition,
extend it above the roof of the building for proper dispersal of the exhaust.
•
Equip the exhaust end of the system with an exhaust stack to improve the overall efficiency
of the system.
•
Make sure the length of the duct that enters into the blower is a straight length at least ten
times the duct diameter. An elbow entrance into the blower inlet causes a loss in efficiency.
•
Position the discharge outlet away from open windows and inlet vents.
Exhaust capacity
•
The system should provide a flow rate of
feet/minute). Measure the flow rate at the inlet to the hood with a suitable air-flow meter to
ensure that the system is drawing properly.
•
Provide make-up air to the laboratory in the same quantity as is exhausted. An 'airtight'
laboratory will cause a loss in efficiency in the exhaust volume.
Blower information
The required capacity of the blower depends on the duct length and the number of elbows or
bends used to install the system. If an excessively long duct system or a system with many bends
is used, a stronger blower may be necessary to provide sufficient exhaust volume.
The blower should be located at least 4 meters (13.1 ft) and not more than 6.5 meters (21.3 ft)
from the inlet directly above the instrument, and should exhaust to the atmosphere or into a
considerably wider exhaust duct.
AAnalyst 200 User's Guide
5600-8400 liters/minute (200–300 cubic
3-13