Under CDM 2015, a client must appoint a principal designer in writing as soon as is practicable, and in any event before the construction phase begins, on any project where more than one contractor will work. HSE's guidance goes further: appoint as early as possible in the design process, at the concept stage if practicable. The legal deadline is the start of work on site. The useful deadline is the first design meeting.
What the regulations say
Regulation 5(1): where there is more than one contractor, or it is reasonably foreseeable that there will be, the client must appoint in writing a designer with control over the pre-construction phase as principal designer.
Regulation 5(2): the appointment must be made as soon as is practicable, and in any event before the construction phase begins.
Regulation 5(3): if the client fails to appoint a principal designer, the client must fulfil the principal designer's duties.
Two words in 5(1) matter. The principal designer must be a designer, and must have control over the pre-construction phase. A consultant with no design role and no control over the design cannot hold it.
What HSE's guidance says
L153 says the principal designer should be appointed as early as possible in the design process, if practicable at the concept stage. Early appointment helps the client pull together the pre-construction information and gives the principal designer enough time to carry out their duties.
It also says the appointment should last as long as there is a need for the role. That includes design work that continues into the construction phase, and issues during construction that need the designs to be modified.
Why late appointment fails
The principal designer's job is to plan, manage, monitor and coordinate health and safety in the pre-construction phase, so that foreseeable risks are designed out where they can be. Most of the decisions that settle those risks are made early: the layout, the structure, the access for maintenance, the sequence the building can be built in.
A principal designer appointed after planning, or as the contractor mobilises, arrives after those decisions are fixed. The appointment is on paper. The influence over the design is not.
There is a second cost. The principal designer must help the client provide pre-construction information to designers and contractors (Regulation 11(6)). If they arrive late, the information the designers and bidders needed was either gathered without them or not gathered at all.
A worked example
A client commissions an architect for a two-storey office extension. The architect produces concept designs, the scheme gets planning, and only when tenders go out does the client appoint a principal designer. By then the roof has no permanent edge protection designed in, and the plant has been placed where it can only be reached by working at height. Appointed at concept, a principal designer would have raised both while they were still lines on a drawing.
Design and build, and novation
Where a concept architect or project manager does the early work and a design and build contractor or novated designer takes over later, L153 notes it may be appropriate to end the first principal designer appointment and appoint a new one. The handover should be planned. See design and build: who carries the designer duties?
Common questions
Is a principal designer needed on a single contractor job?
No. The appointment is required where there is, or will foreseeably be, more than one contractor.
Can the client appoint the architect?
Yes, if the architect is a designer with control over the pre-construction phase and has the skills, knowledge, experience and organisational capability the role needs (Regulation 8).
What if the principal designer leaves before the end of the project?
The health and safety file passes to the principal contractor, and the client should make sure the principal contractor is fully briefed on design matters relevant to the remaining work.
Related: no principal contractor appointed?, pre-construction information and our free design review checklist.
This article is general information, not legal advice.