| Live services (electricity, gas, water): striking buried or hidden services when digging trenches and breaking in at the manhole | Operatives and the excavator operator (electric shock, burns, explosion, fire, crush from flooded trench), householders and neighbours (loss of supply, gas escape, flooding) | CAT and Genny available, permit to dig, trained operatives | 3×5=15 | Get utility and service plans and meter positions from the client before starting. Plan the runs to avoid known services where possible. Scan the whole route with the CAT and Genny in two directions, mark the results, and rescan as the trench deepens and the spoil is dug. Hand-dig trial holes with insulated tools within the agreed safe digging distance of located services and where plans are unclear. Treat unknown services as live. No excavator work over located services. Keep a brief, a banksman and agreed stop-work rule for damage. Follow the Electricity at Work Regulations 1989 and HSE guidance HSG47 Avoiding danger from underground services. Operatives wear insulating gloves and eye protection when hand-digging near services as the last line of defence. | Medium |
| Public / other trades nearby: householders, neighbours, visitors, delivery drivers and the trades building the rear extension entering the work area or the excavator swing zone | Householders, children, neighbours, passers-by on the private driveway, delivery drivers and other trades (struck by plant, falling into trenches, trips over pipes and spoil) | Site cabin and access off the private driveway | 3×4=12 | Agree with Hartley Residential that the work zone is closed to the householders and other trades. Fit Heras or barrier fencing with signs around the open trenches, spoil and excavator swing area, and fit lit or reflective barriers if left overnight. Coordinate the sequence with the extension trades so that they are not working below or alongside the excavator. Keep a banksman for all plant movements and for deliveries. Tell neighbours when digging is under way and when the work will be noisy. Keep the driveway clear of materials so that emergency access is not blocked. Check the barriers daily. Operatives wear hi-vis clothing as the last line of defence. Follow CDM 2015 duties on coordinating and cooperating with others. | Low |
| Trench collapse in excavations up to 1.2m deep, including ground that is wet, loose or disturbed by earlier services | Operatives in the trench (burial, crush injuries, suffocation, fatal injury) | Trench support and shoring, excavation permit, battered ends | 3×5=15 | Do not enter any trench deeper than the ground allows unless it is supported, battered or benched to a safe angle. Fit trench support (boxes, props or sheets) as digging proceeds and keep it within the manufacturer's limits. Dig the shortest practical length and only open what can be laid and backfilled in the shift. Keep spoil and materials at least 1m from the edge. A competent person inspects at the start of each shift, after rain and after any change, and records it. Do not work alone in a trench. Follow CDM 2015 Regulation 22 on excavations. Operatives wear hard hats and safety boots as the last line of defence. | Medium |
| Falling into open trenches, and unsafe trench access with ladders and battered ends | Operatives, householders, children and other trades (broken bones, head injury) | Battered ends and a ladder for access | 3×3=9 | Put barriers or guard rails and toe boards around trenches, with the barrier set back from the edge. Use stop blocks for the excavator and vehicles. Leave a ladder secured, extending at least 1m above the top, and keep the ladder base clear. Keep trenches covered or fenced when not attended and at day end. Check access routes daily. Follow the Work at Height Regulations 2005 for ladders. Anti-slip boots and hard hats as the last line of defence. | Low |
| Mini-excavator (1.5t) operation: overturning, striking or crushing people, and hitting structures, and use of plant for lifting pipes and the manhole cover | Operatives, banksman, householders, other trades and the public (crush, impact, fatal injury) | Operator holds a CPCS or NPORS mini-excavator ticket | 3×5=15 | Confirm which operative is the nominated operator and check their ticket. Complete daily pre-use checks. Plan a one-way route and exclusion zone around the swing radius. Use a trained banksman whenever people are within the work area. Set stop blocks at trench edges and keep the machine level and on firm ground. Use the quick hitch properly with the safety pin fitted. Only lift with rated lifting points and accessories, with the load kept low, under LOLER 1998. Follow PUWER 1998. Operators wear seat belts and everyone near plant wears hi-vis and safety boots as the last line of defence. | Medium |
| Undermining existing house foundations, the new extension footings and nearby structures when excavating close to them | Operatives, occupants and extension trades (structural movement, collapse, crush) | Trench support, excavation permit | 2×4=8 | Confirm foundation depths and positions from the client and the extension drawings before digging, and check the extension designer or building control for any digging near footings. Keep the trench bottom outside the line of the foundations where possible, or use extra support. Do not dig below the underside of existing footings without engineer advice. Check for signs of movement, such as cracks, each shift. Stop work and report to the Principal Contractor if there is any sign of movement. | Medium |
| Manual handling of 110mm and 160mm pipes, bedding bags, concrete bags, manhole cover and frame, and trench support | Operatives (back, shoulder and hand injuries, crush injuries) | 3 operatives available, mini-excavator on site | 4×3=12 | Avoid manual lifting where possible: deliver materials close to the work, use the excavator with a banksman and rated accessories for heavy items and use wheelbarrows. Break loads down and use two-person lifts for pipe lengths and the cover. Use lifting keys for the cover. Rotate tasks and take breaks. Follow the Manual Handling Operations Regulations 1992. Gloves and safety boots as the last line of defence. | Medium |
| Noise and hand-arm vibration from the compactor plate, mini-excavator, and any hand-held breaking or coring tools | Operatives and nearby householders (hearing damage, hand-arm vibration syndrome) | Short 4-day duration | 4×3=12 | Choose low-vibration, well-maintained equipment and compact in thin layers so the plate runs for less time. Rotate operators and limit trigger time, using manufacturer's vibration figures. Keep others away from noisy work and tell the householders and neighbours when it will occur. Follow the Control of Noise at Work Regulations 2005 and the Control of Vibration at Work Regulations 2005. Hearing protection with a suitable rating as the last line of defence. | Medium |
| Biological hazards from foul sewage and drain contents at the existing manhole and foul run, including leptospirosis, hepatitis A and gastro illness | Operatives (infection through cuts, splashes, hand-to-mouth contact) | Site cabin WC, wash facilities and hot water, EUSR Water Hygiene card | 3×3=9 | Avoid contact where possible: do not open the live drain more than needed and plan the connection to limit flow disturbance. Keep clean and dirty areas apart. Cover cuts with waterproof dressings. Wash hands and forearms with soap and hot water before eating, drinking, smoking or leaving. Do not eat in the work area. Clean tools and boots before the cabin. Report any flu-like illness to a doctor and say you work with sewage. Follow COSHH 2002. Waterproof gloves, eye protection and overalls as the last line of defence. | Medium |
| Toxic or flammable gases and oxygen deficiency at the existing manhole (foul drain), and the risk of someone entering the chamber | Operatives (gas poisoning, collapse, death) and anyone trying a rescue | No manhole entry planned in this scope | 2×5=10 | No one enters the manhole or any confined chamber on this job. Lift the cover only with the correct key, keep ignition sources away and let the chamber vent. Work from ground level or from the supported trench. If entry is thought necessary, stop and reassess, as it needs a Confined Spaces Regulations 1997 assessment, a safe system of work and rescue arrangements. Do not do anything that would need breathing apparatus without a trained team. | Medium |
| Respirable crystalline silica (RCS) dust from breaking in, coring or cutting the brick, concrete or mortar of the existing manhole and from cutting concrete or masonry | Operatives doing the work and anyone nearby breathing the dust (long-term lung disease, silicosis, lung cancer) | Work is outdoors in open air | 3×5=15 | Plan the connection to reduce cutting and coring, for example using existing openings or purpose-made fittings. Use on-tool extraction (M-class or H-class vacuum) or water suppression on every drill, corer, breaker and saw used on the manhole walls and benching. Keep others away and clean up with an H-class or M-class vacuum, never dry sweeping or compressed air. Then use RPE with an assigned protection factor of at least 20 (FFP3 disposable or equivalent), face-fit tested and worn clean shaven. Follow the Control of Substances Hazardous to Health Regulations (COSHH) 2002 and HSE Construction Information Sheet CIS36 Construction dust. The RCS workplace exposure limit is 0.1 mg/m3 (8-hour TWA) in HSE EH40/2005. | Medium |
| Disturbing unidentified asbestos-containing materials (for example old pipework, sheeting, coatings or debris in the ground or at the existing manhole and extension tie-in) in a building where the age is not confirmed | Operatives, householders and other trades (asbestos fibre inhalation causing serious lung disease later in life) | Permit to dig and excavation permit | 2×5=10 | Before work starts, check the client's asbestos register or management survey for the work area, as required by Regulation 5 of the Control of Asbestos Regulations 2012. For intrusive work where the register does not cover the area, get a refurbishment and demolition survey of that area first. Record this check on the permit. Brief all operatives to recognise suspect materials. Stop-work rule: if suspect material is found, stop, keep people away, do not touch or sweep it up and report it to the Principal Contractor before work carries on. | Medium |
| Wet concrete (haunching and bedding of the manhole frame): skin burns, dermatitis and eye damage | Operatives (cement burns, dermatitis, eye injury) | Hot water and wash facilities in the cabin | 3×3=9 | Use ready-mixed concrete or pre-bagged mixes to reduce mixing and dust. Mix on a board, away from drains and watercourses, and stand upwind. Wash off splashes straight away and do not let wet concrete rest against skin or kneel in it. Keep skin covered and use barrier cream only as a supplement. Follow COSHH 2002 and the supplier's Safety Data Sheet. Alkali-resistant gloves, eye protection and waterproof boots as the last line of defence. | Low |
| Generator, electrical equipment and fuel: electric shock, fire, carbon monoxide, and fuel spills | Operatives and nearby occupants (shock, burns, fire, poisoning, ground contamination) | Genny on site and wash facilities | 3×4=12 | Use 110V equipment or battery tools and RCD protection for any 230V item. Check leads, plugs and PAT labels, and keep leads off the ground and out of water. Run the generator outdoors, away from windows and doors, on a drip tray, and refuel only when it is switched off and cool. Keep fuel in approved containers in a locked safe place with a spill kit and a fire extinguisher on hand. Follow the Electricity at Work Regulations 1989 and PUWER 1998. | Low |
| Slips, trips and falls on muddy, uneven ground, spoil heaps, pipes and leads, and working in rain, wet trenches or hot sun | Operatives, householders and other trades (sprains, fractures, heat illness, cold) | Site access off a private driveway, site cabin | 4×2=8 | Keep the work area tidy and store pipes, bedding and spoil in set places away from walkways. Use walkways or boards over soft ground and lay leads off the floor. Pump out water from the trench before work and stop work if heavy rain threatens the trench sides, with re-inspection before work starts again. Provide shelter, water and shade in hot weather, and warm rest breaks in cold weather. Anti-slip boots and waterproofs as the last line of defence. | Low |