Construction sector adopts comprehensive prequalification standards to improve safety and compliance

Construction firms are being pushed to show, more clearly than before, that the companies they hire are competent, compliant and safe to work with. For housebuilders and developers, that has made prequalification a central part of risk management rather than a box-ticking exercise.

The complication is that the sector now uses several overlapping terms. PAS 91 has been withdrawn, SSIP is still widely specified, and the Common Assessment Standard, or CAS, is increasingly treated ...

as the benchmark for broader contractor assurance. Knowing which one applies, and at what level, can save time, avoid duplicated paperwork and reduce exposure to safety and compliance failures.

PAS 91 once provided a single, standardised prequalification questionnaire for construction work. Introduced in 2010, it was designed to replace the patchwork of client-specific forms that contractors often had to complete separately. It covered five main areas: health and safety, environmental management, quality, financial standing, and diversity and inclusion. Its value lay in consistency, allowing suppliers to answer one structured set of questions rather than repeating the same information for different buyers.

That model is now history. The British Standards Institution withdrew PAS 91 in April 2023, and it is no longer maintained or recommended by government. In its place, the Common Assessment Standard has become the preferred route for wider construction prequalification, especially for organisations that need assurance beyond basic safety documentation.

CAS builds on the logic of PAS 91 but goes further. Developed by Build UK with CECA and industry specialists, it expands prequalification to 13 areas of risk, including health and safety, building safety, quality, environmental management, identity, information security, information management and anti-bribery controls. The standard has also taken on greater importance since the Building Safety Act 2022, which sharpened expectations around competence and accountability across the supply chain.

According to Build UK and industry guidance, CAS is now the prequalification standard used in central government construction procurement. Its adoption is also widening in the private sector as developers look for a more uniform way to assess contractors, principal contractors and principal designers.

SSIP sits alongside CAS, but serves a different purpose. Safety Schemes in Procurement is not itself an assessment standard. Instead, it is an umbrella framework that brings together multiple health and safety schemes and allows them to recognise one another through mutual recognition arrangements. In practice, that means a contractor assessed under one SSIP member scheme can often be accepted by another without repeating the same health and safety checks.

The system was created to cut duplication, reduce cost and make procurement more efficient. It is commonly used as the baseline test for contractors and subcontractors, particularly where clients want assurance that core health and safety requirements have been met without asking suppliers to complete multiple versions of the same process.

The distinction between SSIP and CAS matters because the two are not interchangeable. SSIP addresses health and safety competence. CAS is broader and is used to evidence a wider organisational picture. In many cases, a developer may require SSIP from subcontractors working on site, while insisting on CAS for key duty holders such as the principal contractor and principal designer.

That layered approach is increasingly common. It allows clients to set a minimum safety standard across the supply chain while reserving the more comprehensive assessment for roles that carry greater responsibility. Used together, the two systems can improve visibility, support more informed procurement decisions and reduce the chance of costly duplication.

For contractors, the practical lesson is simple: the sector has moved away from older, fragmented questionnaires and towards more joined-up assurance. PAS 91 marked an earlier attempt to standardise the process, SSIP remains important for health and safety recognition, and CAS now represents the most complete prequalification framework in common use. As regulation and client expectations continue to tighten, understanding the difference between them has become part of doing business in construction.

Source: Noah Wire Services