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2000 Fire Door-Fan Manual updated 2002-05-28 Page 31 of 58
Deluxe Wind Damping System to Stop Gauge Needles Moving
If the room pressure gauge fluctuates more than 1 Pa due to the wind and the standard two
tube damping system does not reduce them sufficiently then the optional wind damping system
may be more effective. The time constant of the system is designed to decrease swings due to
wind.
If swings are due to other causes the wind damping system may not help.
Place the Deluxe Wind Damping System case on the ground/floor outside the room or building
to be tested. If it has not been stored at the ambient outside temperature, leave it for half an
hour to acclimatise before starting the test. DO NOT let the sun or any other heat source beat
on the capacity tank.
Plug the RED tube coming from the panel into the smallest connector (of the five) on the back
of the capacity tank.
Place the wind damping system in a box and close it up. The box must be on the opposite side
of the doorway from the pressure gauges and away from the air blast of the door fan and the
wind. This is very quick and often sufficient to stop fluctuations.
Observe the gauges. If still fluctuating more than 1 Pa, attach CLEAR tubes (in any
combination of lengths) to each of the four 90
0
connectors on the back of the capacity tank.
Lead the CLEAR tubes to areas around the enclosure as far away from the walls as possible.
Lay the tube flat on the ground and cover the ends with cardboard to stop air movement at the
end of the tube. DO NOT seal the tube ends.
Observe the gauge needle for at least 30 seconds with the blowers off to ensure wind effects
are understood then turn on the blower to establish the required pressure. Again, observe for
at least 30 seconds. Some experimentation may be necessary to get the best gauge readings.
CAUTION: Do not allow tube ends to dip into water because this will seal them off.
If the wind fluctuations are still too great.
Increase test pressure so the wind fluctuations are no more than 20% of measured pressure.
Do not try to measure the static pressure at time of door fan test. Call it zero.
Take the room to the same positive and negative test pressure.
Observe the readings for 60 seconds and take the average.
This procedure will give a slightly (5 to 20%) greater leakage area than a no wind test which
will reduce the retention time by 5 to 20% making the test failsafe.