Xtralis XAS-2-US - Page 37

3.10.2 Duct Pipe Network Installation
Rules
1. While not mandatory, it is recommended that when possible locate probes a minimum of six duct widths
downstream from bends or inlets. Such locations ensure that air flow is non-turbulent and that smoke is
properly mixed with air in the duct for maximum detector/sensor efficiency.
Note: Installation of a duct detector/sensor to a round duct is the same as shown in Figure3-10 and
Figure3-11.
2. Position the probes so that dampers do not restrict air flow at the probe location ("Probe Placement - Location of
Dampers" below).
Figure3-9: Probe Placement - Location of Dampers
Figure3-10: Probe Placement - Bend or Inlet Locations
Figure3-11: Probe Placement - Air Return Inlet Locations
3. Position the probes on the return or supply duct of the equipment’s air handling system. However, probes
should NOT be installed in the return air damper branch (Figure3-9).
4. Position the probes on branch lines if close identification of the alarm source is required.
5. Position the probes on the downstream side of filters to sense fire in filters. However, should the filters block,
sufficient air flow may not be available for proper detector/sensor operation (Figure3-9).
6. Whenever possible, position the probes where they can be conveniently observed.
7. Position the probes in return air ducts ahead of mixing areas.
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