TSI Instruments SUREFLOW 8635-M, Operation And Service Manual

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PART ONE
User Basics
Reading product manuals should not be a difficult and time consuming process. This
section provides a brief but thorough overview of the SureFlow product by maximizing
information with minimal reading. These few pages explain the purpose (The Instrument),
and the operation (Useful User Information, Digital Interface Module, Alarms) of the unit.
Technical product information is available in Part Two of the manual. The manual
focuses on laboratory spaces, but the product information is accurate for any room
pressure application.
The Instrument
SureFlow monitor
measures and reports “room pressure.” Proper room pressure can
control airborne contaminants that can adversely affect experiments, workers in the
laboratory, and people in the laboratory vicinity. For example, laboratories with fume
hoods need negative room pressure (air flowing into the room), to minimize exposure to
people outside the laboratory. The fume hood is the first level of containment, and the
laboratory itself is the second level of containment.
Room pressure, or pressure differential, is created when one space (hallway) is at a
different pressure than an adjoining space (laboratory). When a pressure differential is
created between two spaces, air is forced to flow from the higher pressure space to the
lower pressure space. The direction of air flow is one component of proper room
pressure. The second component of room pressure is the speed or how fast is the air
moving between the two spaces. The SureFlow monitor provides both pieces of
information by measuring whether the air is flowing into or out of a laboratory, and the
speed of the air.
Negative room pressure is present when air flows from a hallway into the laboratory. If air
flows from the laboratory into the hallway the room is under positive pressure. Figure 1
gives a graphic example of positive and negative room pressure.
Figure 1: Room Pressure
An example of negative pressure is a bathroom with an exhaust fan. When the fan is
turned on, air is exhausted out of the bathroom creating a slight negative pressure when