Checking airflow using TR-973 Tight-fitting Air Flow Indicator
Note: The BT-60 Series Breathing Tube or the TR-973 Air Flow Indicator must be connected to the motor blower prior to powering on the blower in
order to activate tight-fitting mode. If the blower is powered on prior to connecting the BT-60 Series Breathing Tube or TR-973 Air Flow Indicator, the
blower will operate in loose-fitting mode. To activate tight-fitting mode the blower must be turned off and restarted with the BT-60 Series Breathing
Tube or TR-973 Air Flow Indicator installed. Tight-fitting mode is indicated on the motor blower when the full facepiece icon is lit (Fig. 3-6). Once the
blower is running in tight-fitting mode it will remain in tight-fitting mode, even if the breathing tube is removed, as long as the blower is not powered
down. In tight-fitting mode, the blower operates at lower preset speeds designed to be more comfortable for the tight-fitting facepiece wearer.
Airflow check
The 3M™ Versaflo™ PAPRs are pre-calibrated to ensure required airflow. However, the 3M™ Tight-fitting Air Flow Indicator TR-973 must be used to
verify minimum required airflow is attained prior to each day's use. The PAPR compensates for changes in air density, which is affected by elevation
and air temperature. During use, if you suspect the PAPR is not delivering a minimum of 4 cfm (113 lpm), exit the contaminated area, see your
supervisor, and recheck the airflow with the 3M™ Air Flow Indicator TR-973. The airflow is checked with your current filter installed.
• Ensure float ball in the TR-973 moves freely in the tube and the gasket at the bottom end of the tube is in place.
• Insert the TR-973 into the outlet of the motor blower unit outlet by aligning the two pins on the AFI to the slots on top of the blower (Fig. 2).
• Turn the motor blower unit on by pressing and holding the power button for 1 second (Fig. 3-1). Run the 3M™ Powered Air Purifying Respirator
for up to 1 minute to allow the airflow to stabilize.
• Ensure the motor blower is operating in tight-fitting mode. Tight-fitting mode is indicated on the motor blower when the full facepiece icon is lit
(Fig. 3-6). Once the blower is running in tight-fitting mode it will remain in tight-fitting mode, even if the breathing tube is removed, as long as the
blower is not powered down.
• With the airflow indicator in a vertical position, ensure that the bottom of the floating ball rests at, or above, the minimum flow mark for the 'letter'
representing your 'Zone' (Fig. 4). Air Flow Indicator must be in the vertical position for an accurate reading.
• The Air Flow Indicator is graduated into different 'zones' based on air density, which is based on elevation and ambient temperature. To determine
your zone, determine the elevation and temperature for the environment where you are conducting the airflow check. See your supervisor if you
are not certain of these values. Find the zone where your elevation and temperature intersect on the chart supplied with the airflow indicator
(Chart 1). For additional guidance on conducting an airflow check, consult 3M Technical Data Bulletin #221 - Conducting airflow check on the
TR-600, or contact 3M Technical Service.
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Fig. 3 - Motor Blower User Interface
1) On/Off button, 2) Flow control button, 3) Airflow setting indicator,
4) Battery charge status level/alarm indicator, 5) Filter loading/
alarm indicator, 6) Tight-fitting mode indicator
Fig. 1
Fig. 2
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Fig. 3
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