BS 54-7:2001 pdf download – Fire detection and fire alarm systems — Part 7: Smoke detectors — Point detectors using scattered light, transmitted light or ionization
4.4 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.
4.5 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 behaviour If there is provision for on-site adjustment of the response behaviour of the detector then:
1) for each setting at which the manufacturer claims compliance with this standard, the detector shall comply with the requirements of this standard, and access to the adjustment means shall only be possible by the use of a code or special tool or by removing the detector from its base or mounting;
2) any setting(s) at which the manufacturer does not claim compliance with this standard shall only be accessible 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(s) are used, the detector does not comply with the standard. NOTE: These adjustments may be carried out at the detector or at the control and indicating equipment.
4.7 Protection against the ingress of foreign bodies The detector shall be so designed 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 may introduce the danger of clogging by dust etc. It may therefore be necessary to take other precautions against false alarms due to the entry of small insects.
4.8 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 detector’s sensitivity to slowly developing fires. Since it is not practical to make tests with very slow increases in smoke density, an assessment of the detector’s response 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 that:
a) for any rate of increase in smoke density R, which is greater than A/4 per hour (where A is the detector’s initial uncompensated response threshold value), the time for the detector to give an alarm does not exceed 1,6 × A/R by more than 100 s; and
b) the range of compensation is limited such that, throughout this range, the compensation does not cause the response threshold value of the detector to exceed its initial value by a factor greater than 1,6.
4.9 Marking
Each detector shall be clearly marked with the following information:
a) the number of this standard (i.e. EN 54-7);
b) the name or trademark of the manufacturer or supplier;
c) the model designation (type or number);
d) the wiring terminal designations;
e) some mark(s) or code(s) (e.g. serial number or batch code), by which the manufacturer can identify, at least, the date or batch and place of manufacture, and the version number(s) of any software contained within the detector.
For detachable detectors, the detector head shall be marked with a), b), c) and e), and the base shall be marked with at least c) (i.e. its own model designation) and d).