Quantcast Rolling Shutters

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8.3.9 Speed Test
On moving walks with DC driving machine motors, or where the speed appears to have been
changed, a speed test should be performed. With no load on the treadway, measure and record
the "no load" speed in feet per minute. This speed should not exceed the rated speed by any
significant amount. Use a tachometer to measure the speed direct or determine the speed by
carefully noting the time, in seconds, for a given step to travel from one combplate to the other.
Then compute the speed using the following formula: S = 60 d/t where S is the speed in feet per
minute, "d" is the distance between the units of the tooth points of the opposing thresholds
measured along the treadway in feet, and "it" is time for the selected pallet or chalk mark to move
from one threshold to the other in seconds.
8.3.10 Rolling Shutters
Where rolling shutters are used to protect floor openings, test the operation of the shutter both
manually and automatically (sensing devices should be checked as outlined in Item 117.1a(7),
Note 2.) Check the manual means, such as a hand crank, and determine that is readily accessible
and visible. If power operated, test the operation of the sensitive leading edge of the shutter to
determine that application of a force not exceeding 20 lbs will stop the shutter and cause it to
reverse for a distance of approximately 6 in.; and that following the removal of the force the
shutter will resume its closing motion until the opening is fully closed. on this test, the initial
movement of the shutter should cause the power circuit to the moving walk driving motor and
brake to open and stop the moving walk and prevent its further operation until the shutter is fully
retracted.
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