Edwards Signaling ReadySet - Manual (Page 26)

Chapter 3: Installation and configuration
18 ReadySET Aspirating Smoke Detection System Installers Handbook
• If the sampling pipe system and ReadySET detector is used as the primary smoke
detection system, methods should be employed to notify stoppage of airflow in the
duct(s).
• The exhaust air from the detector must be returned back to the duct using an
exhaust-port adapter and associated piping. This requirement assures positive
airflow through the detector.
• Locate sampling pipe in the main supply duct return side, downstream of the filters
and a minimum of six duct widths from any source of turbulence (such as bends,
inlets, or deflection plates) to reduce the effects of stratification. In installations
where the filter is capable of removing smoke, install the sampling tube upstream of
the filter.
Note: Where it is physically impossible to locate the sampling pipe in accordance
with this guideline, the sampling pipe may be positioned closer than six duct widths,
but as far as possible from inlets, bends, or deflection plates.
• Locate the sampling pipe such that dampers do not restrict airflow at the sampling
pipe.
• The sampling pipe should be located before air exhausts from the building or before
diluting return air with outside air.
• For accurate identification of the source of an alarm, locate sampling pipe as close
as possible to the protected area's air entry into the duct system.
• Locate sampling pipe on the downstream side of the filter to sense fire in the filters.
Note: If filters are blocked, sufficient airflow may no longer be present for proper
operation.
• Do not locate sampling pipe near outside air inlets except to monitor smoke entry to
the handling system for adjacent areas.
• Whenever possible, locate sampling pipe upstream of air humidifiers and
downstream of dehumidifiers.
Return air grill sampling method
Return air grill sampling systems are designed with sampling pipes centered in the front
of the return air grill. Sampling holes should be spaced so that a minimum of three holes
are used for each grill. Larger grills require more sampling holes. The sampling holes
should be in the direction of the airflow with an end cap.
When using the air grill sampling without another sampling method, the smoke-
detection system will be ineffective when the ventilation system is inoperative. If this
method is being used as the primary smoke detection system, the grill should be
monitored for stoppage of airflow.