AS 7240.12:2018 pdf free.Fire detection and alarm systems Part 12: Line type smoke detectors using a transmitted optical beam.
4.4.2 If there are cables connecting separate parts of the detector, then a means shall be provided for a remote monitoring system (e.g. the fire detection control and indicating equipment) to detect a short or open circuit on those cables, in order to give a fault signal.
4.4.3 If more than one detector can be connected to the transmission path of a remote monitoring system (e.g. control and indicating equipment), the removal of a head from the base shall not prevent an alarm signal from another detector connected to the same transmission path.
4.5 Manufacturer’s adjustments
It shall not be possible to change the manufacturer’s settings except by special means (e.g. the use of a special code or tool) or by breaking or removing a seal.
4.6 On-site adjustment of response threshold value
4.6.1 If there is provision for on-site adjustment of the response threshold value of the detector then
a) for all of the settings at which the manufacturer claims compliance, the detector shall comply with the requirements of this part of ISO 7240 and access to the adjustment means shall be possible only by the use of a code or special tool or by removing the detector from its base or mounting;
b) any setting or settings at which the manufacturer does not claim compliance with this part of ISO 7240 shall be accessible only by the use of a code or special tool, and it shall be clearly marked on the detector or in the associated data that if these setting or settings are used, the detector does not comply with this part of ISO 7240.
4.6.2 These adjustments may be carried out at the detector or at the fire detection control and indicating equipment.
4.7 Protection of optical components
The detector shall be so designed that a sphere of diameter greater than (1,3 ± 0,05) mm cannot pass into any enclosure containing optical components when the detector is in the operational condition.
NOTE This requirement is intended to restrict the access of insects into the sensitive parts of the detector. It is known that this requirement is not sufficient to prevent the access of all insects, therefore, it may be necessary to take other precautions against unwanted alarms due to the entry of small insects.AS 7240.12 pdf download.