Temporary and Construction-Site Fire Detection
A construction or refurbishment site is a high fire-risk environment where the usual safeguards are half-built or absent — compartmentation incomplete, hot works underway, combustible materials and temporary power everywhere. People still need to be warned to get out. This guide covers how fire detection and warning is provided temporarily on site and during building works, and why it has to keep pace with a constantly changing environment.
The defining feature of construction fire cover is that the risk, and the site itself, change week by week — so the arrangement has to change with them.
Who this is for
This is for competent fire alarm engineers involved in temporary fire cover on construction and refurbishment sites, or in the transition to a permanent system. The experience level assumed is competent engineer. Use it for the principles; the specific arrangement comes from the site fire risk assessment, construction fire-safety guidance and BS 5839-1.
Why construction sites need cover
Building sites concentrate fire risk: hot works such as cutting and welding, combustible materials and packaging, temporary electrical supplies, and compartmentation that is incomplete or being altered. At the same time, the people working there need a reliable way to raise the alarm and to be warned to escape. Providing a suitable means of giving warning of fire is part of managing that risk, driven by the site fire risk assessment and the relevant construction fire-safety guidance, within the wider legal duty for fire precautions.
Temporary and wireless arrangements
Temporary fire cover scales with the site. Smaller, lower-risk sites may use simple manually-operated warning devices; larger or higher-risk projects use temporary wireless fire alarm systems with call points, sounders and, where warranted, detection. Wireless systems are well suited to construction because they can be deployed quickly and repositioned as work areas and escape routes change — something hard-wired temporary systems cannot match. The appropriate arrangement is set by the site fire risk assessment and construction fire-safety guidance, not by a fixed template.
Reviewing as works progress
The single most important discipline is review. A construction site is never static: escape routes are opened and closed, work areas move, hot works happen in new locations, and compartmentation is progressively formed or altered. Fire cover that was adequate for one phase can quietly become inadequate in the next. So the fire risk assessment and the alarm arrangement must be reviewed and updated as the works progress. Treating the temporary arrangement as a one-off installation, never revisited, is exactly how gaps in cover appear.
Transition to the permanent system
Most projects reach a stage where the permanent fire alarm system is being installed while temporary cover is still needed. Managing that overlap so that cover is continuous — never a window where the temporary system has been removed but the permanent one is not yet effective — is a key part of the plan. The permanent system then follows the normal route of installation, commissioning and handover to BS 5839-1. From field experience, gaps at this transition, and temporary systems removed too early, are recurring risks worth guarding against.
Common points to check
Recurring issues include temporary cover not updated as the site changed, escape routes altered without reviewing warning coverage, and premature removal of temporary systems before the permanent system was effective. Keeping the arrangement aligned with the current site is the essential ongoing task.
When not to rely on this alone
When not to use this article: do not use it to design construction-site fire cover or set the arrangement for a specific project. That comes from the site fire risk assessment, construction fire-safety guidance and BS 5839-1, applied by competent professionals to the specific site and its phases.
Relevant standards
Permanent fire detection follows BS 5839-1, a code of practice; temporary construction-site fire safety is governed by the site fire risk assessment and construction fire-safety guidance. The legal duty for fire precautions in most workplaces, including construction sites, sits under the Regulatory Reform (Fire Safety) Order 2005, with Building Regulations statutory guidance in Approved Document B applying to the completed building work. Separate the legal duty from the recommended methods when advising a client, and always work to current editions and guidance.
Professional disclaimer
This is an educational and workflow resource for competent engineers and does not replace the site fire risk assessment, construction fire-safety guidance, the current British Standards, or competent judgement. Verify temporary fire cover against current documentation and the site's evolving risk assessment.
Related documentation
Use this with the site fire risk assessment, construction fire-safety guidance, and the current BS 5839-1 for the permanent system. Record the temporary arrangement and review it at each phase of the works, and plan the transition to the permanent system so cover is continuous.