Modular & Volumetric Construction RAMS: Risk Assessments for Off-Site Manufactured Building Installation

Table of Contents

• Why Modular Construction RAMS Matter
• Key Hazards in Modular Building Installation
• Crane Lift Planning and LOLER Compliance
• Module Connection and Structural Stability
• Ground Preparation and Foundation Interface
• What Your Modular RAMS Must Cover
• Frequently Asked Questions
• Next Steps

Why Modular Construction RAMS Matter

Modular and volumetric construction — the installation of factory-manufactured building modules onto prepared foundations — is one of the fastest-growing sectors in UK construction. The installation phase concentrates some of the highest-risk activities in construction into a short programme: multiple heavy crane lifts, working at height on module tops during connection, and the coordination of ground works, structural connections, and services terminations at a compressed pace.

Under CDM 2015, the modular building installation contractor is typically the principal contractor (where they have overall control of the site during installation) or a specialist contractor under a principal contractor. In either case, a comprehensive RAMS covering all phases of the installation must be produced before site possession.

This guide explains what a compliant modular construction RAMS must include, with particular focus on the crane lift and working at height controls that are most frequently underspecified.

Browse all trade RAMS templates on the RAMS AI trade hub — covering 22 specialist construction trades.

Key Hazards in Modular Building Installation

• Crane lifts of heavy modules — Individual volumetric modules can weigh 5-40 tonnes. Each crane lift is a LOLER-regulated lifting operation that requires a specific lift plan, a competent appointed person (AP), and a banksman or signals system for every lift.
• Working at height during module connection — Structural connections between modules are typically made at the roof level of each floor, requiring operatives to work at the module edge at significant heights. Fall prevention is a critical hazard.
• Module instability before connection — A module placed on foundations but not yet connected to adjacent modules or tied down may be unstable, particularly in wind loading conditions.
• Crane ground conditions — Heavy cranes require preparation of crane positions to support their outrigger loads. Inadequate ground preparation is a common cause of crane instability and toppling incidents.
• Pinch points and module landings — As heavy modules are lowered into position, there is a risk of crushing injuries to operatives guiding the module. Exclusion zone management during lifting is critical.
• Services connection and testing — Once modules are connected, services (electrical, plumbing, heating) must be interconnected across module joints. This work involves electrical live working risks.

Crane Lift Planning and LOLER Compliance

Every lift of a volumetric module is a lifting operation under LOLER and must be planned, supervised, and carried out safely. Your RAMS must specify:

• Lift plan requirement — A specific lift plan must be produced for each module lift (or category of similar lifts). The lift plan must specify: module weight, crane type and capacity, lift radius and hook height, rigging arrangement, briefing procedure, and emergency plan if the lift goes wrong.
• Appointed person — A LOLER-competent appointed person (AP) must be responsible for planning each lift. The AP is typically a qualified lift supervisor with CPCS or equivalent certification. Their name and qualification must be stated in the RAMS.
• Rigging and spreader bars — Modules are typically lifted using factory-fitted lifting eyes and a spreader bar to maintain the correct lift angle and prevent distortion of the module structure. Your RAMS must confirm that the spreader bar has a current LOLER test certificate and that all rigging equipment (slings, shackles) has been inspected and is rated for the lift.
• Exclusion zone during lifting — No person may be within the crane's operating radius during a module lift, except for the banksman in a designated safe position with a clear view of the lift. The exclusion zone must extend beyond the footprint of the module to allow for pendulum swing in wind conditions.
• Wind speed restriction for lifting — Module lifts must not proceed when wind speed exceeds the crane manufacturer's safe working limit (typically 12-14 m/s). Specify how wind speed will be monitored (anemometer or weather forecast) and who is authorised to make the go/no-go decision.

Module Connection and Structural Stability

Once modules are landed, they must be structurally connected to adjacent modules and to the foundation structure before they are considered stable. Your RAMS must address:

• Working at height during connection — Structural connections are typically made at the roof-level junction between modules. This requires operatives to work at height, often without permanent edge protection in place at this stage. Specify the temporary edge protection to be installed at each floor level before connection work begins.
• Temporary stability until connection is made — A landed module must be temporarily supported or propped if it cannot be immediately connected. Specify how modules will be temporarily secured — anchor bolts into the foundation, horizontal ties to adjacent modules, or temporary props.
• Connection sequence — Specify the connection sequence: which connections are made first, in what order modules will be connected at each level, and how the partially connected structure will be monitored for stability during the connection phase.
• Weatherproofing at module joints — Module joints must be weatherproofed as part of the installation to prevent water ingress before the external envelope is complete. Specify the sequence for joint sealing and the interim weather protection for the building interior during the installation programme.

Ground Preparation and Foundation Interface

Crane ground conditions and foundation preparation are critical to a safe modular installation:

• Crane pad specification — Specify the crane pad design for each crane position, confirmed by a structural engineer based on the crane's outrigger load and the soil bearing capacity. The crane pad must be installed and cured before crane mobilisation.
• Service identification — Before any crane pads or ground preparation works, service identification (drawings, CAT scan, trial holes) must confirm that no buried services are in conflict with crane pad positions or foundation works.
• Foundation accuracy check — Foundation bolt positions or bearing pads must be checked against the module drawings before the first lift. Alignment errors discovered during lifting are extremely difficult to correct safely. Specify the tolerance check procedure and acceptance criteria before the first module is lifted.

What Your Modular RAMS Must Cover

• Lift plan requirement for every module category (or specific lift plan for complex lifts)
• Appointed person: name, qualification, responsibility
• Crane selection and ground condition specification
• Rigging: spreader bar LOLER certificate, sling and shackle inspection
• Exclusion zone management during lifting
• Wind speed restriction: monitoring method, go/no-go decision authority
• Module stability before connection: temporary propping specification
• Connection working at height: temporary edge protection at each floor level
• Foundation accuracy check procedure and tolerance
• Services connection: electrical live working controls
• Weatherproofing sequence: joint sealing and interim weather protection
• CDM pre-start briefing record

Frequently Asked Questions

Does each individual module lift need a separate lift plan, or can one lift plan cover all similar lifts?

Where modules are identical in weight, rigging configuration, and lift geometry, a single lift plan covering all lifts of that module type is acceptable, provided the lift plan includes all relevant variables (crane position, radius, height) for each lift location. However, any lift that is substantially different — heavier module, greater radius, limited access for the crane, or unusual rigging arrangement — requires a separate specific lift plan. The appointed person must review every lift plan and confirm it is appropriate for each lift before that lift proceeds.

What happens if a module is out of tolerance when it lands on the foundation?

The module must be lifted off and the problem investigated — do not attempt to force a module into position by tapping or pushing. Tolerance errors are typically caused by foundation inaccuracy, module distortion during transport, or rigging errors. Once the cause is identified, the foundation or module must be corrected before the lift is re-attempted. Document the tolerance error, the investigation, the corrective action, and the outcome of the re-lift. Report any significant tolerance issue to the modular building designer and the principal contractor.

Who is responsible for the crane ground condition assessment — the crane operator, the installation contractor, or the principal contractor?

The crane operator is responsible for the safe operation of the crane, which includes refusing to operate if ground conditions are inadequate. The crane hire company will typically specify minimum ground bearing requirements. However, the installation contractor (or principal contractor, if they are in that role) is responsible for ensuring that the ground at each crane position meets those requirements and for producing any crane pad design required to achieve them. In practice, both parties should review ground conditions jointly and agree in writing that conditions are suitable before the crane is mobilised.

Next Steps

Your modular construction RAMS should be developed for each project, as crane positions, module weights, and foundation types vary significantly. RAMS AI generates comprehensive modular construction risk assessments pre-populated with the lift planning, stability, and connection hazards described in this guide.