VDOT-ASD-400 Aspiration Detector
Velocity Detection
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VDOT-ASD-400 Aspirating Smoke Detector User’s Manual V1
ensure that transit times, balance of suction and individual sampling point sensitivity are
within desired limits.
l
System Sensitivity: The recommended maximum number of sampling holes on the pipework to
achieve desired relative sampling hole sensitivity is as follows
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Class A: 40 holes
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Class B: 60 holes
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Class C: 100 holes
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In Consideration of both maximum pipework and system sensitivity, the recommendation of
pipe length and number of holes to achieve different sensitivity of VDOT-ASD-400 are
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EN54-20 Class A: Maximum 40 holes totally
4x100m (4x10 holes)
3x100m (3x13 holes)
2x100m (2x20 holes)
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EN54-20 Class B: Maximum 60 holes totally
4x100m (4x15 holes)
3x80m (3x20 holes)
2x60m (2x25 holes)
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EN54-20 Class C: Maximum 100 holes totally
4x60m (4x25 holes)
