Temporary works and high-risk activities

Temporary works are the structures a project needs to build the permanent one and then takes away: excavation support, falsework and formwork, scaffolding, propping, hoardings, crane bases and working platforms. They fail differently from permanent works, because nobody designed the building around them and they are altered, loaded and struck by the people on site. BS 5975 sets the code of practice for temporary works procedures, and the industry has built its control system around it: a designated individual with overall responsibility, a temporary works coordinator on each project, temporary works supervisors, a register of every item, a design brief and design check for each, and a permit to load and a permit to strike.

CDM 2015 adds the legal spine. Regulation 19 requires all practicable steps to prevent a structure becoming unstable during construction; regulation 22 requires excavations to be supported where there is a risk of collapse, and regulation 24 requires them to be inspected at the start of every shift and after any event likely to have affected their strength or stability; regulation 20 governs demolition and dismantling; and the Work at Height Regulations 2005 govern every working platform.

The high-risk activities a site safety adviser reviews and manages are the ones that kill: deep excavations, lifting operations, work at height, demolition, work near live services and the interfaces between them. Each needs a task-specific RAMS, a competent supervisor, a permit where the control depends on sequence, and someone independent who checks that what is on paper is what is on the ground.

Questions about Temporary works and high-risk

What does a temporary works coordinator do?

Under BS 5975 the temporary works coordinator is appointed by the principal contractor for a project and is responsible for making sure every item of temporary works is identified on the register, has a design brief and a checked design, is built as designed, is inspected before loading and before striking, and is only loaded or struck under a permit. The coordinator does not have to design the works; they have to control them.

How often must an excavation be inspected?

Under regulation 24 of CDM 2015, by a competent person at the start of every shift in which work is carried out in it, after any event likely to have affected its strength or stability, and after any accidental fall of rock, earth or other material. A written report is required after the first inspection in each seven-day period and after any event that prompted an inspection.

Does a small excavation need support?

The regulation is about risk, not depth. Any excavation where there is a risk of a person being buried or trapped by a fall or dislodgement of material must be prevented from collapsing, by support or by battering back, and the risk in a shallow trench in poor ground can be as real as in a deep one.

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