Explainer: The principal designer role

In the Construction (Design and Management) Regulations 2015 (CDM 2015), the Health and Safety Executive (HSE) defines the principal designer as an organisation or individual that is appointed by a client to take the lead in planning, managing, monitoring and coordinating health and safety during the pre-construction phase of a project that involves – or is likely to involve – more than one contractor. 

 “As soon as you get two contractors, you need a principal contractor and a principal designer,” says Lloyd Edmonds, associate at consultancy Mott MacDonald. “This is for domestic clients as well as large projects. Most house extensions have got at least two contractors.”

The principal designer has an important role to play in influencing how the risks to health and safety should be managed, because design decisions taken during the pre-construction phase can have a significant impact on whether a project is delivered in a way that secures the health and safety of everyone affected by the work. 

 A principal designer must be a designer, as defined in CDM 2015, but they do not have to carry out actual design work on the project. What is important is that they have control over the pre-construction phase and possess the relevant skills, knowledge and experience – or, if they are an organisation, the organisational capability – to carry out all of the functions of the role. 

The level of skills, knowledge and experience should be proportionate to the complexity of the project and the range and nature of the risks involved. This includes:

• The technical knowledge of the construction industry relevant to the project
• The ability to understand, manage and coordinate the pre-construction phase (including ensuring that significant and foreseeable risks are managed through the design process) and any design work carried out after construction begins

Examples of how a principal designer might demonstrate their skills, knowledge and experience include:

• Records of continuing professional development (CPD)
• Membership of professional institutions or bodies

Examples of demonstrating organisational capability include:

• Using pre-qualification assessment services from third-party assessors, such as those who are members of the Safety Schemes in Procurement Forum (SSIP)
• Self-assessing using the standard health and safety pre-qualification questions in Publicly Available Specification PAS 91

CDM 2015 requires the principal designer to be in control of the pre-construction phase. Where design work is carried out, the principal designer role requires designer-led design risk management. Typically, the organisation undertaking the lead designer role will be best placed to undertake the principal designer role, as they have control over the design process and are already doing a lot of the coordination of other design issues. However, when there is more than one contractor but no traditional design work, a principal designer is still required for the preparatory work.

Mott MacDonald principal designer Sarah Jensen says principal designers need a combination of specific ‘hard’ expertise – such as the relevant Institution of Occupational Safety and Health (IOSH) or National Examination Board in Occupational Safety and Health (NEBOSH) qualifications – and ‘soft’ skills, such as communication.

 “You need to be quite forthright, because there may be times when you will have to say that a project isn’t ready to proceed, or the design or construction team can’t do something they want to,” she says. “But you also have to be able to listen, to understand when something is an absolute no for a designer or when they are saying, ‘That’s going to be really difficult’ – and being able to negotiate a way through that. That’s why project management experience is very useful, as well as design experience.”

Major consultants and clients have developed competency matrices to identify the skills needed in the role, and put together principal designer teams for complex or multi-site projects to ensure all skills are covered. An example of a competency matrix, produced by Mott MacDonald, is presented below.

The HSE says that the principal designer should be appointed by the client as early as possible in the design process – if possible at the concept stage – and stay in place as long as there is a need for their role to be performed. 

 “A lot of engineers don’t seem to understand that principal designers are needed from the get-go – when [the project] is just an idea,” Jensen says. “Even if it’s a design competition, you need to be applying the CDM Regulations. If it’s a conceptual design, or a feasibility – call it what you will – it is a design.”

She gives the example of a new school building project, early discussions for which might include whether the school would be built on a new site or on the existing site alongside the operational school: “These decisions are usually made pre-feasibility, but they have a massive impact on the running of the project.”

The principal designer needs to be appointed early in the project to have maximum influence. If they are appointed too late, then many of the key decisions that influence health and safety risk will have been taken and it will be difficult to change them.

Equally, it is important for the principal designer to remain in place as long as design or preparatory work is still being carried out on the project, which can be for the duration of construction. Many projects are still having elements of the permanent works designed while construction is under way, and almost all require temporary works design throughout construction, so the pre-construction phase can last for the entire length of the project.

More information about the interaction between the principal designer and temporary works designers can be found on the Temporary Works Forum website.

As shown in the graphic above, the principal designer role involves close cooperation with both the client and the principal contractor, as well as coordinating the work of other people in the project team to ensure that significant and foreseeable risks are managed throughout the design process. 

The principal designer can get the design team to identify the key risks and then either eliminate or reduce them through design. If it is not reasonably practicable to eliminate or reduce the risks, the principal designer can encourage the designers to provide information on those risks that would not be obvious to competent contractors.

The way a principal designer carries out their duties will vary depending on the complexity and size of different projects, and there is no single methodology that will work in every situation. However, the HSE provides guidance on CDM 2015 and what each dutyholder must or should do to comply with the law to ensure projects are carried out in a way that secures health and safety.

CDM 2015 does give some very specific instructions about how the principal designer should perform their role, including, for example, preparing a health and safety file appropriate to the characteristics of the project and assisting the principal contractor to prepare a construction phase plan.

 “The regulations are very carefully worded, and actually provide written instructions,” says Jensen. “The principal designer is not here for auditing or a compliance check – they’re an integral part of the design team.”

When it comes to best practice, the first priority for a principal designer is to ensure that the CDM Regulations are followed, and that notifications are issued at the appropriate time.