F&RM Journal FPA Main Site
ACCESSIBILITY

A high-rise building with multiple occupation types, such as the WRaP building, is a complex structure requiring specific fire protection and life safety considerations. Based on its characteristics, including a height over 18m and the inclusion of residential units, this building would be subject to the Gateway regime required for Higher Risk Buildings. The design development process concerning fire-related aspects of the building should begin at Gateway 1, which now requires fire safety considerations to be integrated into the design proposals at the planning stage and a fire statement/fire safety information to be submitted with a planning application.

Before construction starts, a Full Plans Application at Gateway 2 must demonstrate how the building proposals comply with the requirements of the building regulations requirements. This would include considering the whole building lifecycle, maintenance, management, and behaviours and characteristics of the end-users in all parts of the building, including residential, commercial, and office areas. This process would require proactive liaison with statutory bodies such as the Building Safety Regulator, fire and rescue services, and Building Control, as well as input from specialist consultants, including a fire engineer.

Fire safety considerations

On a building of this type, a fire engineer would be typically responsible for the development of the fire strategy for the building, including fire detection and alarm systems, sprinkler systems, smoke control systems, means of escape (including the requirement for a second staircase coming into effect on 30 September 2026 and evacuation strategies for different occupancy types), emergency lighting, signage, and access and facilities for rescue. An architect typically coordinates the agreed fire strategy requirements into the overall architectural design, including specifications, drawings, and detailed proposals.

Some of the key fire safety considerations that an architect working on this building would be required to take into account during the design development stage include:

  • Fire compartmentation: Ensuring the appropriate standard of fire compartmentation to prevent the spread of fire between different uses (commercial, office, and residential uses) and within those occupancies, with reference to Section 8 of Approved Document B. The design development would include the consideration of fire-resistant walls, floors, and doors, addressed by performance specification (by stipulating the required standard of fire resistance, typically in minutes), and/or by reference to specific products and/or systems that can be demonstrated to achieve the required fire resistance through appropriate fire tests.
  • Passive fire protection: Specifying other passive fire protection solutions such as fire-stopping, cavity barriers, and structural fire protection, with reference to Sections 7, 9, and 10 of Approved Document B.
  • Modular build components: Ensuring that modular build components meet fire resistance standards and are properly installed on site to maintain the integrity of fire compartments. This would include, amongst other things, addressing tolerances and dealing with any deviations in dimensions on site, including at junctions and interfaces of different trades.
  • External wall construction: Ensuring that the external wall construction complies with the combustibility requirements of the Building Regulations.
  • Roof materials: Considering the use of non-combustible roof materials and elements with fire-resisting covering, where applicable, to prevent fire spread in the event of a fire caused by PV panels.
  • Car park: Ensuring that a car park incorporating EV spaces is designed to meet a relevant standard and perform in the fire in a manner consistent with its design. Some of the considerations would include adequate classification of linings to meet Requirement B2 of the Building Regulations, including for insulation if installed to the underside of the ceiling or wall, and the provision of appropriate ventilation with input from a mechanical and electrical (M&E) engineer.

Any high-rise building with multiple occupations requires careful consideration of fire safety-related issues. Taking the WRaP building as an example, the key considerations from an architect’s perspective would include adequate fire compartmentation, passive fire protection measures such as fire-stopping and cavity barriers, and the use of non-combustible materials in external walls and roof construction. The design process would require proactive liaison with statutory bodies and input from specialist consultants, including a fire engineer.

One of the fundamental purposes of a specification is to provide clear and precise information to ensure that all stakeholders, including employers, architects, and contractors, are aligned in their understanding of the project requirements.

Writing specifications

The architectural specification is a critical component of design information, which when read together with drawings, forms the comprehensive basis for communicating the employer’s requirements in the design and construction process. Whilst drawings show the physical relationships between building components, the specification details materials, products, methods of installation, workmanship, and required quality standards in order to define the quality of these components. One of the fundamental purposes of a specification is to provide clear and precise information to ensure that all stakeholders, including employers, architects, and contractors, are aligned in their understanding of the project requirements. In forensic investigations, the architectural specification, which is likely to be a contract document, often acts as the critical point of reference to determine what had been agreed between the parties as a requirement for the project. A disagreement between the parties over the interpretation of specification typically arises as a result of poor drafting and the lack of clarity and consistency in the specification document.

The role of specification

The RIBA Plan of Work 2020 refers to an Outline Specification at the ‘Concept Design’ and ‘Spatial Coordination’ stages, during which it not only conveys the requirements for the project but also assists in the production of the Cost Plan and thereafter in the tendering process. The Final Specification is then developed at the end of the ‘Technical Design’ stage.

The type of specification produced by the design team would depend on the nature of the project and the employer’s expectations and quality aspirations. For example, performance specifications outline the desired outcomes and performance criteria and standards that must be met for particular construction elements, while prescriptive specifications provide details of specific materials, product manufacturers, and construction methods. In recent years, there has been a shift from prescriptive specifications towards performance specifications, which define the employer’s requirements for the contractor design portions of the works. This allows a specialist sub-contractor to prepare the detailed specification and provide the specific manufacturing and fabrication information.

The Final Specification, together with drawings, should provide the comprehensive and co-ordinated information, including all the required standards to which the contractor will build the works. For example, a drawing will show the location of a cavity barrier within the external wall construction, but the specification will detail the material or product to be used or its required fire performance and provide instructions on installation and quality control.

Common challenges

Some of the most common issues concerning specifications encountered during forensic investigations of a dispute, include the following.

  • Ambiguities in the specification, including vague language, undefined terms, or inconsistent use of terminology or requirements in the document.
  • Conflicts where different parts of the specification contradict each other or clash with other project documents, including drawings. In situations, where there are discrepancies between specifications and drawings, it is often unclear what document takes precedence. The inclusion of different or conflicting requirements in the specification might lead to disagreements over what was required for the project, including the quality and/ or the performance of a particular element of construction.
  • The lack of clarity between different types of the specification when both are referred to under one item of work. Whilst it is possible to include items from the prescriptive specification, such as products and/or manufacturers, in the descriptive specification, if it is not clear and precise, such a combination may blur the lines of the design responsibility of relevant parties.
  • Critical errors, including those resulting from the lack of understanding of the relevant standards or regulations, or the applicable requirements for a particular item of works.

Addressing these common issues by a designer would enhance the accuracy and reliability of specifications for construction purposes and consequently mitigate disagreements over the interpretation of the specification in case of a dispute.

Adhering to industry standards and regulations within the specification is also essential.

Best practices for writing specifications

Writing effective specifications is crucial to achieve the required standard of the installation and construction on the project. Best practice includes ensuring that specifications are clear and unambiguous. For example, using simple, direct, and precise language, clearly defining any technical terms used in the document and referring to the exact standards and requirements to define the quality of the works, rather than using undefined terms such as ‘high quality’.

Another key component of the specification is maintaining consistency to ensure that the relevant stakeholders interpret the specification in the same way. This would not only mean consistent formatting and terminology but also ensuring that the requirements for a particular element of construction, for example cavity barriers or fire-stopping (often used interchangeably), are consistent across the entire document.

Adhering to industry standards and regulations within the specification is also essential. Whilst various software tools, such as National Building Specification (NBS), offer features that aid the creation, management, and revision of specifications, it is important for designers to familiarise themselves with the relevant standards and regulations that apply to the project, and to use these tools to enhance their understanding of what they are specifying, rather than relying solely on the technology to do the job.

Finally, it is also important to make sure that specifications are coordinated and consistent with other project documents, such as drawings, to create integrated design information for the project. This can be achieved by conducting regular reviews and regular cross-referencing following the changes to identify and address potential conflicts.

Summary

Together with drawings, architectural specifications play a pivotal role during the design and construction processes. Specifications provide both a framework and direction for the contractor to build the works, stipulating the quality and types of materials, methods of installation, and the standard of workmanship required under the contract. Unclear or inconsistent specifications may lead to disagreements between the parties over what was actually required for the project.

Magdalena Prus

Article written by
Magdalena Prus
BA(Hons), DipArch, RIBA, MSc (Construction Law), FCIArb HKA Global

MORE FEATURED ARTICLES

Testing the façade
Façade fire spread
The rise of photovoltaics