Función “Curvas Hidrostáticas”

This is a very important section of the code, which follows on naturally from the section concerned with design, as the code places the primary responsibility on avoidance of false alarms on the designer of the system. However, the majority of Section 3 should be read by all parties involved in the system, from the person who first specifies that a system should be provided through to the system designer, the installer (to a much lesser extent), the commissioning engineer, the maintenance organization and the actual user of the system. It is intended that this ‘cradle-to-grave’ approach to limitation of false alarms, within the current code, will, over time, make a major impact on what remains, at the time of writing, an unacceptable rate of false alarms from automatic fire detection and alarm systems.

Contents of the code 30 Responsibility for limitation of false alarms

It is this clause that places the various responsibilities on all the relevant parties, as described above. In the case of those responsible for servicing the system, a responsibility to carry out a preliminary investigation arises if, on inspection of records, it is determined that the rate of false alarms exceeds a level specified within the clause.

31 Categories of false alarms

This clause acknowledges that false alarms do not emanate solely (or even primarily) from equipment faults. Four categories of false alarm are defined, only one of which relates to faults in equipment.

If the matter of false alarms is to be tackled successfully, on a global basis or specific installation basis, it is necessary for a universal language to be adopted in respect of the nature of false alarms; this is the significance of clause 31 of the code.

The only recommendation within this clause relates to recording of the category of false alarm by users.

32 Acceptable rate of false alarms

This is a very important clause within Section 3 of the code. It acknowledges the fact that no installation will be entirely immune from false alarms. Having done so, it then offers benchmarks against which the rate of false alarms generated by any particular system can be judged as acceptable or not.

Since the number of false alarms is likely to be directly proportional to the number of automatic fire detectors, the benchmark rates are expressed in units of one false alarm per specified number of detectors per annum. An in-depth investigation is recommended if specified benchmarks are exceeded.

It should also be noted, at this stage, that, within a previous clause (clause 30), the commentary asserts that systems that produce unacceptably high rates of false alarms need to be regarded as not complying with BS 5839-1; such non-compliance could have implications, of course, in respect of legal liability, insurance and civil liability. It is clause 32 that, no doubt, would be used as the basis for any associated assertion that the rate of false alarms was unacceptable.

Such an assertion might conceivably be regarded by an enforcing

authority as a breach of the Regulatory Reform (Fire Safety) Order in England and Wales.*

33 Causes of false alarms

The commentary within this clause provides information on recognized causes of false alarms and recommends that those responsible for specification, design, commissioning or maintenance of fire alarms should be conversant with them.

34 Design process for limitation of false alarms

This clause is aimed particularly at the system designer. It makes recommendations for formal consideration of the potential for false alarms at the design stage, with appropriate review and, if necessary, suitable modification of the design, prior to its completion.

35 Measures to limit false alarms

This clause provides all parties with specific and practical measures that should be taken to avoid false alarms from both manual call points and automatic fire detectors. As well as considering the selection and siting of these devices, recommendations are provided for suitable selection of system type (e.g. analogue or multi-sensor), protection against electro-magnetic interference, performance monitoring of newly commissioned systems and measures to filter out false alarms (e.g. by a ‘staff alarm’

arrangement). The clause also acknowledges the importance of suitable servicing and maintenance of the system.

Section 4 – Installation

This section is the shortest in the code, reflecting the fact that the role of the installer is simply to install the system in accordance with the requirements of the designer and with recognized good installation practices, such as those embodied in BS 7671 (IET Wiring Regulations).

* and equivalent legislation in Scotland and Northern Ireland.

Contents of the code 36 Responsibility of installer

Notwithstanding the principal duties and role of the installer, as described above, this clause recommends that the installer give consideration to certain basic recommendations contained within Section 2 of the code.

37 Installation practices and workmanship

This clause recommends a number of basic good installation practices in conjunction with those contained within BS 7671.

38 Inspection and testing of wiring

This clause sets out the tests that should be carried out on completion of wiring, or sections of wiring, by the installer. It should be noted that further tests will, of course, be carried out as part of the commissioning process, but these are described in Section 5 of the code (see below).