Fire suppression system readiness between inspections

1 Introduction
2 Inspection and maintenance intervals
3 Conditions between inspections
4 Reducing the interval between condition checks
5 Limitations of condition monitoring
6 Related articles on Designing Buildings

[edit] Introduction

Fire suppression systems installed in buildings require appropriate inspection, testing and maintenance to ensure that they remain capable of performing their intended function. The nature and frequency of these activities depend on the type of system, the hazards it is intended to control and the applicable standards and regulatory requirements.

Periodic inspection provides evidence of the condition of equipment at the time it is examined. It does not, by itself, establish the condition of the equipment continuously between inspections. Additional routine checks, monitoring and maintenance can provide greater assurance that a fault or change in condition is identified promptly.

[edit] Inspection and maintenance intervals

[edit] Legal duties

Under Article 17 of the Regulatory Reform (Fire Safety) Order 2005, the Responsible Person must ensure that fire safety equipment and facilities provided for the protection of relevant persons are subject to a suitable system of maintenance and are maintained in an efficient state, in efficient working order and in good repair.

The legal duty is continuous, whereas the inspection and maintenance activities used to demonstrate that equipment is being maintained are carried out at specified or risk-based intervals. Records of inspection, testing and maintenance can provide evidence of the arrangements in place, but the existence of an inspection record does not establish that equipment has remained fault-free at all times since the previous inspection.

[edit] Fixed gaseous fire suppression systems

Fixed gaseous fire extinguishing systems are covered by BS EN 15004-1. Carbon dioxide systems are additionally subject to BS 5306-4.

BS EN 15004-1 provides requirements and recommendations for the inspection and maintenance of fixed gas extinguishing systems. The frequency of inspection depends on the system and its components, and maintenance should be undertaken by competent personnel. Carbon dioxide systems also require periodic checks of cylinders, associated equipment and the protected enclosure. BS 5306-4 includes provisions for determining whether changes to the enclosure could adversely affect system performance.

Electrical fire detection and control equipment associated with a suppression system should be inspected and maintained in accordance with the applicable requirements for the fire detection and alarm system. BS 5839-1 covers fire detection and fire alarm systems in non-domestic premises and its current edition is BS 5839-1:2025.

[edit] Portable fire extinguishers

Portable fire extinguishers are covered principally by BS 5306-3 for commissioning and maintenance and BS 5306-8 for selection and positioning.

BS 5306-3 recommends that portable extinguishers receive a basic service at least annually by a competent person. Extended servicing and overhauls are required at longer intervals, depending on the type of extinguisher. The standard also recommends that the Responsible Person, or an appropriately nominated person, carries out visual inspections at least monthly, with more frequent inspections where circumstances require.

Monthly visual inspections are intended to identify readily apparent problems such as incorrect location, obstruction, damage, signs of operation or other conditions that could affect availability. They are not a substitute for the periodic service carried out by a competent person.

[edit] Other fixed suppression systems

Different types of fixed fire suppression system are subject to different standards and maintenance requirements. Sprinkler systems are covered by BS EN 12845, while water mist systems are covered by the BS EN 14972 series. BS 5306-0 provides general guidance on the selection and application of fixed firefighting systems and other fire equipment.

The inspection and maintenance regime should therefore be established for the particular type of system rather than assuming that a single inspection interval applies to all suppression equipment.

[edit] Conditions between inspections

Periodic inspection creates an interval during which the condition of equipment is not being formally assessed by the person responsible for its inspection. The length and significance of this interval depend on the equipment and the nature of the failure that might occur.

For portable fire extinguishers, a monthly visual inspection provides an opportunity to identify an extinguisher that has been discharged, damaged, obstructed or otherwise rendered unavailable. The annual basic service provides a more detailed assessment.

For fixed gaseous suppression systems, the interval between formal inspections can be substantially longer. A system may therefore develop a fault, lose pressure or otherwise become incapable of performing as intended after an inspection and before the next scheduled examination. This does not mean that the standards regard the system as acceptable in a failed condition; rather, it illustrates the limitation of any periodic inspection regime.

Different failure modes also have different characteristics. A discharge is generally a discrete event that can leave the equipment in an obvious changed state. Pressure loss may occur gradually and can remain below an inspection threshold after one inspection and exceed it before the next. Electrical or control faults may generate local indications that require someone to observe and act on them.

Some suppression equipment and control systems can record activations, faults or other operating information. Where such information is available, it can provide additional evidence of equipment condition, although the information is only useful if it is retrieved, interpreted and acted upon appropriately.

[edit] Reducing the interval between condition checks

[edit] More frequent inspection

The most straightforward way of reducing the period during which a fault can remain undetected is to increase the frequency of inspection. This provides more frequent physical verification of equipment but also increases inspection requirements and associated costs.

More frequent inspection does not provide continuous assurance. A fault can still occur immediately after an inspection and remain undetected until the next inspection unless another means of identifying it is available.

[edit] Monitoring through control systems

Some suppression systems incorporate control panels capable of monitoring system status and generating fault indications. Where the system is connected to a suitable building management or remote monitoring arrangement, these indications may be communicated to a person or service responsible for responding to them.

The capabilities of such arrangements vary. Monitoring may identify particular faults or changes in system status without providing a complete assessment of the physical condition or performance of the suppression system.

[edit] Retrofitted condition monitoring

Condition monitoring can also be added to existing suppression equipment where suitable measurement points or status signals are available. Depending on the equipment, monitoring may detect a discrete condition, such as a change in pressure-switch status, or continuously measure a parameter such as cylinder pressure.

Continuous measurement can provide information about trends that may not be apparent during periodic inspection. For example, a gradual reduction in cylinder pressure can potentially be identified before it reaches a level at which the system is unable to operate as intended.

Wireless monitoring can be useful where suppression equipment is located in areas without convenient power or data cabling. Radio performance is affected by the construction and layout of a building, including walls, floors, metalwork and other obstructions. The performance of a particular wireless system therefore needs to be established for the installation rather than assumed from its nominal transmission range.

[edit] Limitations of condition monitoring

Condition monitoring of suppression equipment is not the same as fire detection. A device that monitors pressure, valve position or another equipment parameter does not necessarily detect fire, smoke or heat and does not constitute a fire detection and alarm system.

Monitoring also does not replace the inspection, testing and maintenance activities required by applicable legislation, standards or the system manufacturer's maintenance instructions. Its principal benefit is to provide additional information about equipment condition between scheduled inspections.

The usefulness of monitoring depends on the parameters that can be measured. If a suppression system does not provide an accessible pressure connection, electrical contact or other suitable indication, monitoring may require modification of the equipment. Such modifications need to be considered carefully because they may affect the design, approval, certification or reliability of the suppression system.

An alert is only effective if it reaches someone able to assess the situation and take appropriate action. A monitoring system should therefore have a defined alarm-routing and response procedure, including arrangements for investigating alerts and restoring the equipment to an operational condition where necessary.

Condition monitoring should consequently be regarded as an additional layer of assurance rather than a replacement for established inspection and maintenance arrangements.