Excavation work in the UK is governed by CDM 2015, the Construction (Health, Safety and Welfare) Regulations 1996 (where they still bite — most provisions are now in CDM), and a body of HSE guidance led by HSG47 (Avoiding danger from underground services) and HSG150 (Health and safety in construction). The dominant hazards are service strike, trench collapse and contaminated ground. A strong excavation RAMS treats each as a named topic with its own controls, not as a single line in a hazard list.
Service strikes — gas, electric, water, telecoms — cause the largest single share of excavation injuries in the UK. HSG47 (3rd edition) sets out the SLOC method: Survey, Locate, Observe, Care. The RAMS must show evidence of each step: the desktop service-records search (LSBUD or equivalent), the CAT scan results with serial number of the instrument and date, the digging-method controls (hand-dig within 500mm of any service, no power tools within 300mm of any electrical service), and the supervisor's authority to stop work on any unexpected finding.
The LSBUD (LinesearchbeforeUdig) free service covers most national infrastructure. Local utilities (DNOs, water companies, fibre operators) must be searched separately — the RAMS should name the providers searched and the reference numbers of the responses.
HSE statistics show that trench collapse fatalities are almost always in excavations between 1.2m and 3m deep — the range where contractors are most tempted to skip support. The RAMS must specify the support method for any excavation over 1.2m: battering to a safe angle (typically 1:1 in firm ground, flatter in unstable ground), shoring (timber, hydraulic or proprietary), or a trench box. Generic 'support as required' wording is the most common single reason an excavation RAMS gets sent back.
For any excavation in unstable, made or saturated ground, the support specification should be signed off by a temporary works coordinator (TWC) — this is the BS 5975 standard the industry has converged on. The TWC's name and registration should appear in the RAMS.
Much of the urban UK sits on made ground — historical landfill, demolition rubble, former industrial sites. The RAMS should reference the Phase 1 desktop study and Phase 2 intrusive investigation (if available), name the contaminants of concern (typically hydrocarbons, heavy metals, asbestos in demolition fill), and set out the controls during dig (PPE category, decontamination, segregation of arisings). For sites within 250m of a former gasworks, brownfield register entry or historical industrial use, contaminated ground should be assumed until proven otherwise.
For sites with a confirmed asbestos-in-soil risk, CAR 2012 applies — the RAMS should describe how arisings will be sampled, segregated and disposed of, and whether removal is licensed or non-licensed work.
Once an excavation exceeds 1.2m depth or accumulates standing water, the Confined Spaces Regulations 1997 (SI 1997/1713) may apply — particularly where there is biological or chemical hazard (sewer connections, gas migration from made ground). The RAMS should set out the entry procedure: atmospheric monitoring (oxygen, LEL, H2S, CO), continuous attendance at the surface, rescue equipment on standby and a named emergency procedure that does not depend on fire-and-rescue arrival times.
For any excavation where standing water cannot be managed by pump alone, the RAMS should reference the rescue plan for a casualty in water and the buoyancy aids on site.
Each hazard paired with the UK regulation or HSE guidance document that applies.
Strike on buried gas, electric, water or telecoms service
HSG47 + EAWR 1989
Trench collapse and fall-in
CDM 2015 + HSG150
Falls into open excavations
WAHR 2005 + CDM 2015
Contaminated or made ground exposure
COSHH 2002 + CAR 2012
Plant stability near excavation edges
CDM 2015 + Site Code of Practice
Confined-space entry below 1.2m with biological / chemical hazard
CSR 1997 + L101
Drowning in flooded excavation
CDM 2015
Patterns we see when principal contractors send excavation RAMS back for re-work.
The legal framework a excavation RAMS operates inside — all links point to the official source.
SI 2015/51
The primary law on construction-site management — covers excavation duties on PC, contractor and designer.
HSG47 (3rd ed)
The SLOC method (Survey, Locate, Observe, Care). Cite this in any excavation RAMS.
HSG150 (3rd ed)
General construction-safety guidance with significant excavation content.
SI 1997/1713
Applies to deep excavations and any excavation with biological / chemical hazard.
BS 5975:2019+A1:2023
The industry standard for temporary works management — names the temporary works coordinator role.
Not automatically, but you must risk-assess it. The 1.2m threshold is industry convention, not a statutory line — CDM 2015 reg 22 requires support where any person could be at risk, regardless of depth. In made ground, saturated ground or near a structure, support may be required at 600mm or less. The RAMS should name the threshold for the specific ground conditions, not default to 1.2m.
LSBUD (LinesearchbeforeUdig) is a free online service that returns the records of most UK national infrastructure operators within minutes. It is not mandatory by law, but using it (or an equivalent multi-utility search) is the de-facto evidence that the contractor has discharged the SLOC duty under HSG47. The RAMS should reference the LSBUD search reference number.
Battering means cutting the sides of the excavation back to a stable angle — typically 1:1 in firm ground, flatter in unstable ground. Shoring means installing supports (timber, hydraulic struts, sheet piles) against the excavation walls. A trench box is a proprietary steel cage lowered into the excavation that protects operatives inside it without supporting the walls themselves. The right choice depends on ground conditions, the work being done, and the proximity of structures.
The TWC is the named competent person under BS 5975 who takes responsibility for the design, installation, monitoring and removal of temporary works on a project. For most excavation work over 1.2m in unstable ground, or for any complex temporary works (sheet piling, ground anchors, cofferdams), a TWC is the industry-standard expectation and many principal contractors require one in the RAMS.
Stop work immediately, withdraw operatives, and re-survey. The RAMS should give the supervisor explicit authority to stop work without referring upwards and should set out the protocol: protect the service in place, contact the utility's emergency line, and do not resume until the find is logged and the support method or route is re-assessed. Unexpected finds are common — the document should treat them as a planned-for event, not an emergency.
City-specific local context — council, HSE office and local building stock notes — for excavation contractors.
Riskora prompts for the council permits, building stock and access constraints that apply wherever the job is — these are the excavation details principal contractors check first in each city.
Generate a preview first. Sign up only when you want to save, edit or export.
Final RAMS must be reviewed and approved by a competent person before use.