[edit] Introduction

[edit] Purpose and regulatory framework

Unlike completed buildings, construction sites are dynamic environments where escape routes, work areas and fire risks may change frequently. A temporary fire alarm system provides a reliable means of alerting everyone on site to a fire emergency, particularly where personnel are dispersed across multiple floors or within temporary accommodation.

The provision of suitable fire precautions is supported by a number of legislative and industry requirements. The Health and Safety at Work etc. Act 1974 places general duties on employers to protect employees and others affected by their work. The Regulatory Reform (Fire Safety) Order 2005 requires fire risks to be assessed and managed in most non-domestic premises, while the Construction (Design and Management) Regulations 2015 require fire risks to be eliminated or reduced so far as is reasonably practicable and managed throughout the project.

The primary function of a temporary fire alarm system is to provide early warning of fire and facilitate safe evacuation. Systems may comprise manual call points, audible sounders, visual alarm devices and, where appropriate, automatic smoke or heat detectors. Activation of either a detector or a manual call point initiates a site-wide alarm to warn occupants.

Temporary systems may be either wired or wireless. Wired systems can be suitable for smaller sites with relatively stable layouts but may be vulnerable to damage during construction activities and can require significant alterations as the project progresses.

Wireless systems communicate using radio technology and can generally be relocated or expanded more easily as the site develops. They are commonly used on larger or more complex construction projects where building layouts and work areas change frequently.

The selection of an appropriate system should be based on the findings of the fire risk assessment and the nature, scale and duration of the project.

The design of a temporary fire alarm system should ensure that all occupants receive prompt and unambiguous warning of fire. Alarm signals should be readily distinguishable from other site noises and be clearly audible throughout occupied areas. Where background noise levels are high, or hearing protection is routinely worn, visual alarm devices should supplement audible alarms.

Manual call points should be positioned so that occupants can raise the alarm without travelling excessive distances, while automatic fire detection may be appropriate in higher-risk locations and in temporary buildings such as site offices, welfare facilities, storage areas and sleeping accommodation where provided.

The alarm system should be considered as part of the overall site fire safety strategy, taking account of escape routes, assembly points, temporary buildings, phased construction and changing site conditions. The fire risk assessment should be reviewed regularly as the project progresses and updated whenever significant changes occur.

Temporary fire alarm systems require regular inspection, testing and maintenance throughout the construction period. Weekly functional testing is widely recognised as good practice and typically involves operating a different manual call point on each occasion to verify that the system correctly transmits the alarm and activates all warning devices.

Inspection records should be maintained, faults rectified promptly and battery condition monitored where battery-powered equipment is used. Periodic servicing by a competent person helps ensure that the system remains reliable as site conditions evolve. Recommendations for testing and maintenance are set out in BS 5839-1, although they should be applied appropriately to the temporary nature of construction site installations.

All personnel should receive induction and periodic refresher training so that they understand the alarm signal, know how to raise the alarm and are familiar with evacuation procedures and assembly points. Site managers should ensure that fire risk assessments remain current and reflect changes in site layout, construction activities and occupancy.