How to control a contractor scope change after work starts

When contractor work changes from the agreed scope or method, pause the affected activity and decide whether the existing risk assessment, method statement, permit, people and coordination still cover it. Identify new hazards, agree controls, revise the relevant documents and brief the team before restarting.

This is not a rule that every tiny adjustment needs a new 30-page RAMS. A change needs a proportionate review based on what it alters. HSE’s contractor guidance says that if different needs emerge or the job changes during work, return to the planning stage; its general risk guidance says controls and records should be reviewed when workplace changes create new risks. HSE: managing contractors (HSG159); HSE: risk assessment steps.

Recognise the changes that matter

Use a short list of triggers rather than debating whether a change is “major”. Consider changes in what is done, for example a pipe now cut rather than just inspected, which brings new dust, asbestos or isolation issues. Consider changes in where, such as a route moving into an unassessed riser or ground work becoming roof work; in how, such as a different machine or a wet method becoming dry; in who, such as a specialist leaving or a night shift having no one trained in the rescue method; in when; and in what else is happening nearby, such as two trades now sharing a zone. These are prompts for review, not automatic conclusions that work is unsafe.

First response: stop the affected part and stabilise the area

“Stop all site work” may be unnecessarily broad; “continue until management signs a form” may be dangerous. The supervisor should identify the affected task and connected activities, make plant, openings, materials and isolation safe within the team’s competence, and keep people out of a newly hazardous area while the change is assessed. If the change is a suspected asbestos-containing material, a utility strike or a failed safety system, follow the specific site emergency arrangements. Raise the change promptly to the person who controls the work and the site controller; a worker should not be penalised for reporting a mismatch between paper and site.

Compare old assumptions with the new job, then agree who approves

Put the current RAMS, permit, drawings and site plan beside the changed task. Ask which hazards were assessed and which were not, identify new exposure pathways and affected people, and review the whole control hierarchy. Can the change be avoided, done from another location or with a lower-risk method? Consider knock-on effects: a new access route can obstruct escape; an extended shift can remove the competent person from the rescue plan. There are several decisions and one signature may not cover them all: the contractor controls its method; the client or principal contractor may control access, interfaces and whether the revised operation can take place alongside others; a specialist may need to assess a material or design. A commercial variation order agrees price and time but does not by itself assess safety.

Update only the documents affected, keep them consistent, and rebrief

A changed method may require a revised risk assessment, method statement, permit, lifting plan, COSHH assessment or traffic arrangement, but the test is whether a person relying on a document would make a wrong decision if it stayed as it is. Make the change obvious and cross-check for contradictions: if a permit authorises a MEWP but the revised RAMS says tower scaffold, one is wrong. Approval is incomplete until the people doing or exposed to the work know the revised method. Brief the crew, shift relief, subcontractors and nearby teams, remove obsolete copies, and confirm understanding of important controls.

Verify the restart conditions

Before work restarts, check the new controls exist where they are needed: correct equipment present and checked; specialist information arrived; other trades out of the changed area; permit reissued or amended; competent people and rescue arrangements present on this shift; crew briefed. A desktop approval without these physical checks is incomplete. Record the restart time and authoriser, and review the change after work resumes. Did the revised method work, or create another interface issue?

FAQs

Sources

• HSE: managing contractors, HSG159
• HSE: using contractors, INDG368
• HSE: risk assessment steps
• HSE: contractor duties under CDM

Related: managing contractors in shared workplaces, work at height rescue plan, and RAMS explained.

In this series: managing contractors in a shared workplace, contractor competence vs accreditation, contractor completion evidence.