Securiton ASD 531, Technical Description, Page: 27 / 105

Design
ASD 531, Technical description, T 140 416 en 27 / 105
3 Design
3.1 Mechanical
The ASD 531 aspirating smoke detector consists of the detector housing and a sampling pipe tube network. The sampling pipe
is made of hard PVC or ABS tubes with an external diameter of 25 mm and an internal diameter of 20 mm (see also Sec. 5.3).
In special applications – e.g. in extremely corrosive environments – other tube materials can also be used, subject to the
specifications set out in Sec. 5.3. The sampling pipe has several sampling holes whose size is such that each hole extracts the
same amount of air. The sampling pipe may be I-, U-, T-, H-, or E-shaped. The sampling pipe is symmetrically designed in
principle. Asymmetrical sampling pipe tube networks can also be implemented with the help of the “ASD PipeFlow” calculation
software.
The housing cover on the detector housing is opened by means of four rotary snap locks.
Integrated in the detector housing is a fan which, in conjunction with the sampling pipe, ensures an uninterrupted supply of air
to the detector housing. Airflow monitoring detects any pipe blockages and pipe breakages in the sampling pipe.
There is one chamber for the smoke sensor in the detector housing. The air channel through the smoke sensor and fan are
separated from the other parts inside the detector housing; this means the ASD 531 is able to remain fully operational during
commissioning and maintenance work even when the housing cover is open.
The AMB 31 Main Board contains the processor-controlled evaluation electronics and the connection technology. There are
two slots in the detector housing for installing optional additional modules (XLM 35, RIM 36).
Pre-defined labelling strips are used for labelling the control unit in the housing cover. If the device is mounted in a position ro-
tated by 180°, the labelling strip can be turned accordingly.
Notice
The XLM 35 and RIM 36 additional modules are optionally available and are built into the ASD 531 when setting
up the system. A maximum of two modules can be fitted.