06 Jun, 2024

Understanding the Issue

In the construction industry, different aspects of a project are often managed separately, each progressing at its own pace. Imagine the four primary construction packages as distinct silos:

1. Structural

2. Architectural

3. Mechanical, Electrical, and Plumbing (MEP)

4. Passive Fire Protection (PFP)

Unfortunately, passive fire protection is frequently neglected during the early design phases until decisions in the other three silos have already been made and implemented. This can result in significant issues, as choices made in these early stages can create obstacles for effective fire protection later on.

Disjointed Progression Through the RIBA Plan of Work

Each silo typically moves through the RIBA Plan of Work independently and at different times. For example, the structural package might advance through RIBA stages 0, 1, 2, 3, 4, and 5 before the passive fire protection package has even reached stages 2 or 3. Consequently, structural elements that are already being erected on-site may need to be revisited and modified to accommodate fire protection requirements, leading to delays and increased costs.

Incomplete Designs and On-site Changes

Consider a scenario involving a steel frame with a cross-laminated timber (CLT) floor slab. There is no standard for the fire resistance of this combination, though some ad-hoc testing and guidance are under development. Additionally, there are no DIAP/EXAP rules for services passing through the timber slab. Such issues typically arise when the passive fire protection package reaches RIBA stage 3, while the structural package is already in stage 5 and under construction.

Similarly, on-site design changes, such as adding ducts for increased ventilation, can require cutting holes into structural elements like steel beams, compromising the fire protection measures previously applied. These unanticipated modifications can lead to significant costs, such as reinforcing cut steelwork or installing entirely new fire protection systems on already coated steelwork.

Building Safety Act Changes – Implications

Historically, construction projects have often followed a Construct-Design Approval model, with considerable overlap between stages. However, the Building Safety Act introduces stringent controls to mitigate these issues.

Gateway 1: RIBA Stage 0

This stage, implemented in October 2022, involves the planning application with stricter requirements for fire statements and the competence of those preparing and scrutinising them.

Gateway 2: End of RIBA Stage 4

Since October 2023, construction cannot commence until the Building Safety Regulator confirms that the design meets safety requirements, providing a "hard stop" to prevent premature construction.

Gateway 3: End of RIBA Stage 5

This stage pertains to the completion and final certification before occupancy.

These gateways ensure that each phase is completed and approved before moving to the next, making it illegal to start construction before the design is approved and to build anything other than the approved design.

Responsibility for Passive Fire Protection Design

Determining responsibility for passive fire protection design is challenging. Typically, this responsibility is passed from the Principal Designer (PD) to the Principal Contractor (PC) and then to the Specialist Contractor, who is often required to revise decisions made 12-18 months earlier.

Ultimately, Principal Designers hold the legal responsibility for the design of passive fire protection. However, they often lack experience in this area. To address this, the Association for Specialist Fire Protection (ASFP) has released Advisory Note 33 (found via the following link - https://asfp.org.uk/page/ASFPTechnicalDocuments), which will provide guidelines to mitigate these risks. We also advocate for early discussions and design meetings involving the PD, PC, and specialist sub-contractor to preemptively address potential issues.

By integrating passive fire protection considerations early in the design phase and adhering to the structured phases introduced by the Building Safety Act, we can avoid costly modifications and ensure the safety and compliance of construction projects.