CDM regulations and concrete scanning — the principal contractor's responsibilities
CDM 2015 places duties on principal contractors to manage pre-construction information — including the location of buried services and structural reinforcement. Here is where scanning fits.
The Construction (Design and Management) Regulations 2015 — CDM 2015 — set out who is responsible for managing risk on a construction project and how. Concrete scanning is not named in the regulations, but it sits squarely inside the duties they impose. If you are a principal contractor planning intrusive work, scanning is one of the practical ways you discharge those duties.
This post explains where scanning fits in the CDM framework, and why treating it as an optional extra is hard to defend.
Pre-construction information and the unknowns it should cover
CDM 2015 requires that pre-construction information be gathered and passed to those who need it. This information should describe the hazards that are reasonably foreseeable — including the things that cannot be seen. Buried services, post-tensioned tendons, reinforcement layout and concealed structural elements are exactly the kind of foreseeable hazard the regulations have in mind.
The difficulty is that pre-construction information is often incomplete. Record drawings are out of date, as-built details were never produced, or the structure has been altered since. Where the information that should describe a hazard simply does not exist, the duty does not disappear. It becomes a duty to find out. Scanning is the most direct way to convert an unknown into known, recorded information.
The principal contractor’s planning and management duties
A principal contractor under CDM 2015 must plan, manage and monitor the construction phase so that, so far as is reasonably practicable, work is carried out without risk to health or safety. Drilling, cutting or coring into concrete that may contain live services or tendons is a clear risk, and “reasonably practicable” is the test the regulations apply.
Scanning before intrusive work is a well-established, proportionate control. It is widely available, it is not disproportionately expensive relative to the consequences it prevents, and it produces a record. When a control is that readily available, choosing not to use it is difficult to justify against the reasonably practicable standard. If something goes wrong, the question asked afterwards will be why a routine and inexpensive check was skipped.
Designers, the principal designer and the information flow
CDM duties do not fall on the contractor alone. Designers must take account of foreseeable risks and provide information about significant ones. The principal designer coordinates this during the pre-construction phase. Where a design relies on fixing into, penetrating or breaking out existing concrete, the realistic position is that the existing reinforcement and services are unknown until verified.
Good practice is for the design team to flag this and for scanning to be planned into the information flow, not left for the site team to arrange under pressure on the day. A principal contractor receiving pre-construction information should check whether the concealed conditions have been addressed, and commission scanning where they have not.
Putting scanning into the construction phase plan
The construction phase plan is the document that records how health and safety will be managed during the works. Where the project involves intrusive work into concrete, the plan should say how concealed hazards will be controlled. In practice that means:
- Identifying which works involve drilling, cutting or coring.
- Stating that scanning will be carried out before those works.
- Describing how scan results will be recorded and communicated to operatives.
- Setting out what happens when a scan finds something unexpected.
A construction phase plan that names scanning as the control, and a permit system that will not release intrusive work until a scan record exists, together demonstrate that the risk has been planned and managed rather than left to chance.
Risk assessments, method statements and the operative briefing
CDM is delivered on the ground through risk assessments and method statements. A method statement for drilling or coring should reference the scan, state that intrusive work will not proceed without a clear result, and explain how marked-out positions are confirmed. The operative carrying out the work needs to know that a scan has been done and what it found — information that has been gathered but never communicated has not controlled anything.
This is also where scan records earn their place. A dated scan record, retained with the method statement, shows that the control named in the plan was actually applied.
Records, retention and the health and safety file
CDM 2015 requires a health and safety file describing information likely to be needed for future construction, maintenance or demolition. Scan records have a natural place here. A reinforcement or services survey carried out for one project remains useful to the next team that has to work on the same structure. Retaining scan data in the file is both good asset management and a contribution to the safety of future work.
The practical position
Scanning is not a regulatory tick-box; it is one of the clearest ways a principal contractor demonstrates that a foreseeable, serious risk has been managed by reasonably practicable means. Build it into the pre-construction information request, name it in the construction phase plan, tie it to the permit system, brief the operatives on the results, and retain the records. Do that, and scanning stops being an optional cost and becomes part of how CDM duties are met — and evidenced.