A construction site is a building with its fire protection removed and its ignition sources multiplied. Compartmentation is incomplete, escape routes change weekly, hot works are happening, and the permanent alarm system either does not exist yet or has been isolated. Temporary detection exists to bridge exactly that period, and the duty to provide it sits with the principal contractor.
Why the site is the hard case
The things a finished building relies on are the things a site has not got. Fire doors are propped or missing, voids are open, stairs may be the only route and may be obstructed, and the people at risk change daily. At the same time hot works, temporary heating, waste and flammable storage all raise the chance of ignition. Risk goes up as protection goes down, which is the whole argument for temporary systems.
What the arrangement has to achieve
Everybody on site must be warned quickly enough to get out, wherever they are working, including in areas where machinery is running and hearing protection is worn. On a small site an air horn and a clear procedure can be adequate. On a large or multi storey site that stops being credible, and linked temporary call points and sounders, usually radio linked so they can be moved as the site changes, are the practical answer.
Who is responsible
Under construction health and safety law the duty for emergency procedures and for preventing fire on site sits with the contractor in control, and the arrangements have to be in the construction phase plan rather than in somebody's head. HSE publishes detailed guidance on fire safety in construction, and it is the document a site should be able to name when asked what its arrangements are based on.
Handing over to the permanent system
The transition is the dangerous moment, because both systems can end up partly isolated at once. The changeover should be planned, dated and recorded: what is covered by which system on which day, who confirms the permanent system is commissioned, and when the temporary equipment comes out. Doing it by assumption is how a building ends up occupied with neither system live.
Questions people ask about temporary fire alarm system
Does a construction site need a fire alarm system?
It needs arrangements that warn everybody in time. On a small open site that can be a horn and a procedure; on a large or multi storey site a linked temporary system is normally the only credible way to achieve it.
Who provides the temporary fire alarm?
The contractor in control of the site, as part of the construction phase plan. It is not something to leave to whoever happens to be on site first.
Can temporary systems be hired?
Yes, and radio linked temporary systems are normally hired rather than bought precisely because they must move as the site changes. The hire should include the servicing regime, not just the boxes.