As a site manager you sit in the middle of the legal chain. You are the person most likely to be asked 'who was responsible' if something goes wrong, so you need to know where your duties start and stop.
The Health and Safety at Work etc. Act 1974 (HASAWA) is the main UK law. It sets a general duty on employers to ensure, 'so far as is reasonably practicable', the health, safety and welfare of employees and anyone else affected by the work, such as visitors or the public.
'So far as is reasonably practicable' means you weigh the risk against the cost, time and effort of controlling it. If the risk is small and the fix is huge, less may be required. If the risk is high, you are expected to act even at high cost.
The Management of Health and Safety at Work Regulations 1999 require every employer to carry out suitable and sufficient risk assessments and to appoint a competent person to help meet legal duties. On a construction site this competent person role often sits with the site manager or a nominated safety advisor.
The Construction (Design and Management) Regulations 2015 are the construction-specific rulebook. They name five duty holders: client, principal designer, principal contractor, designers and contractors. As site manager you usually act for the principal contractor, meaning you plan, manage and monitor health and safety during the construction phase and produce the construction phase plan.
Section 7 of HASAWA places a duty on every employee to take reasonable care of themselves and others affected by their acts, and to cooperate with their employer on safety. This applies to you as an individual, not just as a manager.
The Health and Safety Executive (HSE) enforces the law through inspectors. They can issue an Improvement Notice (time to fix a breach) or a Prohibition Notice (stop the activity immediately, used when there is risk of serious personal injury). Breaching HASAWA is a criminal offence and can lead to unlimited fines or imprisonment for individuals.
A risk assessment identifies hazards on a task or site, works out who could be harmed and how, and sets controls to reduce the risk to an acceptable level. Under the Management of Health and Safety at Work Regulations 1999, every employer must carry out a 'suitable and sufficient' risk assessment for work activities. There is no legal duty to write it down if you have fewer than 5 employees, but on construction sites written RAs are standard practice and expected by CITB/SMSTS.
Always apply controls in this order, not just PPE: eliminate the hazard; substitute with something safer; use engineering controls (guards, extraction); use administrative controls (training, signage, permits); PPE is the last resort, used to cover residual risk only.
A method statement sets out how a task will be done safely, step by step. It should flow directly from the risk assessment: every significant risk identified in the RA must have a matching control described in the MS. Together these are usually called a RAMS document. RAMS must be site-specific, not generic, and reviewed if the task, site conditions, or personnel change significantly.
The site manager must ensure RAMS exist before high-risk work starts, that operatives have read and understood them (briefed and signed), and that the controls described are actually being followed on the ground, not just on paper. A RAMS pack that nobody has read is worthless.
The Construction (Design and Management) Regulations 2015 set out who is responsible for health, safety and welfare on every construction project in the UK, from a domestic loft conversion to a major civil engineering scheme. The core idea is simple: everyone who can affect health and safety through their decisions - client, designer, contractor - has a legal duty, not just the site manager.
On domestic projects the client duties normally pass automatically to the contractor (single contractor) or the principal contractor (multiple contractors), unless a written agreement says otherwise.
A project must be notified to the HSE using an F10 form if construction work will last longer than 30 working days AND have more than 20 workers working simultaneously at any point, OR the work exceeds 500 person days. The Principal Contractor usually submits the F10.
Candidates often think CDM only applies to big sites - it applies to ALL construction work, however small. Another common mistake is confusing the Principal Designer's role (pre-construction, design coordination) with the Principal Contractor's role (construction phase, day-to-day site management). As Site Manager you will usually be acting for, or working closely under, the Principal Contractor.
As the person managing the site day to day, you need to know the Construction Phase Plan exists, keep it live and updated, ensure the F10 (if required) is displayed, and understand that your legal duty runs alongside the client's and designer's - CDM shares the responsibility, it does not remove yours.
Work at Height Regulations 2005 (WAHR) apply whenever someone could fall a distance that could cause injury - there is no minimum height. The hierarchy is: avoid work at height if possible, then prevent falls (guardrails, MEWPs, scaffolding), then minimise the distance and consequences of a fall (nets, airbags, harnesses) if it cannot be avoided.
Any excavation deeper than 1.2metres generally needs support (shoring, battering or benching) unless a competent person has assessed the ground as stable - but collapses happen in shallow trenches too, so never assume.
Don't rely on a risk assessment alone without physical control measures in place; don't let ladders be used for prolonged or heavy work; don't skip the 7-day scaffold inspection just because nothing looks different; don't assume a trench that was safe yesterday is safe today - ground conditions change with weather and vibration.
Good welfare provision is a legal duty, not a nice-to-have. It sits under the Construction (Design and Management) Regulations 2015 (CDM 2015), Schedule 2, and site managers must check facilities are in place before work starts and kept clean throughout.
Required where workers are exposed to noise, vibration, hazardous substances, or ionising radiation above trigger levels. Records must be kept and reviewed.
Fire needs three things: fuel, oxygen and a source of ignition. Take one away and there is no fire. Sites are high risk because they mix flammable materials (packaging, timber, insulation, LPG, solvents) with hot work (welding, grinding, cutting) every single day.
A fire risk assessment is a legal requirement under the Regulatory Reform (Fire Safety) Order 2005. It must be suitable, sufficient, and reviewed whenever the site layout or work activity changes significantly. The Site Manager (or a competent 'responsible person') owns it, not the fire brigade.
Hot work needs its own permit-to-work system. Before starting: clear combustibles at least 10 metres away or screen them off, have a fire extinguisher and a fire watcher present, and keep the fire watch going for at least 60 minutes after work finishes, because smouldering material can flare up later.
Every site needs a fire plan: clear escape routes kept unobstructed, a means of raising the alarm everyone understands, and a nominated assembly point away from the building. Escape routes must never be less than 45 metres to a place of safety on most construction sites unless a fire engineer says otherwise, and travel distances should be checked as the building rises. Extinguishers must be sited at fire points, correctly colour-coded, and checked regularly. Never fight a fire that is beyond an early, small stage.
The standard rule for site tools is 110V centre-tapped-to-earth supply, giving only 55V to earth if a fault occurs, which is far safer than 230V. All electrical equipment needs a documented inspection and test regime, commonly called PAT testing, at intervals based on risk. Cables must be kept off the ground where reasonably practicable, protected from damage, and never run through standing water. Report and take damaged equipment out of use immediately, tagging it 'do not use'.
Segregation is the number one control: keep pedestrians and vehicles apart with barriers, dedicated walkways, and separate site entrances wherever possible. Where segregation is not fully possible, use one-way systems, banksmen, high-visibility clothing, and clear signage. Reversing is one of the biggest killers on site, so minimise reversing manoeuvres, use reversing alarms/cameras, and always use a trained banksman for blind reversing. All drivers and operators of plant must hold the correct certificate of competence (for example CPCS or NPORS) for that specific machine.
Assuming a fire risk assessment is a one-off document rather than a living one. Forgetting the post-hot-work fire watch. Running 230V tools on a construction site. Letting pedestrian and vehicle routes cross without a control.