AS 7240.7:2018 pdf free.Fire detection and alarm systems Part 7: Point type smoke detectors using scattered light, transmitted light or ionization (ISO 7240-7 :2018, MOD).
4.3 Individual alarm indication
Each detector shall be provided with an integral red visual indicator by which the individual detector releasing an alarm can he identified, until the alarm condition is reset. Where other conditions of the detector may be visually indicated, these shall be clearly distinguishable from the alarm indication, except when the detector is switched into a service mode. For detachable detectors, the indicator may be integral with the base or the detector head.
NOTE The alarm condition Is reset manually at the control and indicating equipment (see ISO 7240-2).
The visual indicator shall be visible from a distance of 6 m in an ambient light intensity up to 500 lx at an angle of up to:
a) 5° from the axis of the detector in any direction, and
b) 450 from the axis of the detector in at least one direction.
4.4 Connection of ancillary devices
The detector may provide for connections to ancillary devices (remote indicators, control relays, etc.), but open- or short-circuit failures of these connections shall not prevent the correct operation of the detector.
4.5 Monitoring of detachable detectors
For detachable detectors, a means shall be provided for a remote monitoring system (e.g. the control and indicating equipment) to detect the removal of the head from the base, in order to give a fault signal.
4.6 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.
4.7 On-site adjustment of response behaviour
If there is provision for on-site adjustment of the response behaviour 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 document and access to the adjustment means shall he 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 document 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 this setting or settings are used, the detector does not comply with this document.
These adjustments may be carried out at the detector or at the control and indicating equipment.
4.8 Protection against the ingress of foreign bodies
4.8.1 Closed detectors
Closed detectors shall be designed so that a sphere of diameter (1,3 ± 0,05) mm cannot pass into the sensor chamber(s).
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, however it is considered that extreme restrictions on the size of access holes can introduce the danger of clogging by dust etc. It can therefore he necessary to take other precautions against false alarms due to the entry of small insects.
4.8.2 Open detectors
The open detector shall be designed such that
a) a sphere of (1,3 ± 0,05) mm diameter cannot pass into any enclosure containing active optoelectronic components;
b) a total block of the detector surface shall not cause an alarm but shall signal a fault;
c) an object moving with minimum distance of 6 mm ± 1 mm to the nearest point of the surface of the detector shall not cause an alarm but shall signal a fault.
4.9 Response to slowly developing fires
The provision of “drift compensation” (e.g. to compensate for sensor drift due to the build-up of dirt in the detector), shall not lead to a significant reduction in the sensitivity of the detector to slowly developing fires (see Annex L).
Since it is not practical to make tests with very slow increases in smoke density, an assessment of the response of the detector to slow increases in smoke density shall be made by analysis of the circuit/software, and/or physical tests and simulations.
The detector shall be deemed to meet the requirements of this clause if this assessment shows the following:
a) that for any rate of increase in smoke density R, which is greater than 25 % of the initial uncompensated response threshold value of the detector, Athu, per hour, the time for the detector to give an alarm, does not exceed 1,6 x (Ath,:R) by more than 100 s;
b) that the total compensation c is limited such that c < 0.6 Ath,u throughout this range, and that the fully compensated response threshold value Ath,c does not exceed its initial value Ath.u by a factor greater than 1,6.
4.10 Requirements for software-controlled detectors
4.10.1 General
The requirements of 4.10.2 and 4.10.3 shall be met for detectors which rely on software control in order to fulfil the requirements of this document.AS 7240.7 pdf download.