N93-601-00 Issue 1
Page 7 of 25 © Protec Fire Detection PLC 2015
3.3
Scatter Chamber Detector
The Scatter Chamber Detector (SCD) operates by measuring the light scattered by the air within the scatter
chamber.
A photo sensitive sensor element is placed in a dark chamber with a high brightness light source that
cannot be ‘seen’ by the sensor. When smoke is present the light is scattered in all directions, some of
which is detected by the sensor and relates to the amount of smoke present.
The scatter chamber detector in the Cirrus Hybrid is very sensitive, many times more than that of the point
detector and so can be used in an aspirating system which has considerable dilution from clean areas.
3.4
Hybrid
As scatter chambers are as sensitive to dust as they are to smoke, the hybrid system utilises the cloud
chamber as the primary detector which is not affected by dust with a boost signal when the scatter
chamber detects the smoke. Using the two technologies allows the Cirrus Hybrid to make the fire decision
even earlier whilst minimising the detection of false alarms.
The features of the Protec Cirrus Hybrid Aspirating Smoke Detector are:
Incipient fire detection via Cloud Chamber
Detector technology
High performance optical smoke detection
via Scatter Chamber Detectors
Up to 4 detection areas
LED status indication; to indicate supply
healthy, fault, pre-alarm and fire
Protec addressable protocol
On-board short circuit isolator
Common Fault output contact
5 Programmable output contacts
3 Programmable input contacts
Airflow monitoring per pipe channel
Variable blower speed control
7” Full colour LCD touch screen display for
fault reporting and ease of setup
Commissioning menu; access code protected
Remote network via TCP/IP