Last reviewed 9 May 2020

Compartmentation restricts the spread of fire and associated by-products such as smoke and gases. Mike Sopp reports on how to prevent this control being compromised by contract work.

Protection through sub-division

The most effective way of reducing the spread of fire within premises is by sub-dividing the building into the smallest practicable compartments of fire-resisting construction. Through the application of UK Building Regulations, compartmentation is seen as an integral design feature of a building, which is intended to protect life in the event of a fire.

Passive fire protection

Passive fire protection (PFP) products are those “built in” to the fabric of a building to restrict the growth and spread of fire. One such PFP method is the division of the building into fire-resistant compartments.

British Standards define a fire compartment as “a building or part of a building, comprising one or more rooms, spaces or storeys, constructed to prevent the spread of fire to or from another part of the same building, or an adjoining building”. Therefore, the compartmented area could be a single room, or a series of rooms, even an entire floor area. Alternatively, it could be a vertical or horizontal service space.

According to Approved Document B to the Building Regulations, compartmentation has two objectives.

  1. To prevent rapid fire spread, which could trap occupants of the building.

  2. To reduce the chances of fires becoming large (on the basis that large fires are more dangerous).

Obviously, for compartment walls and floors to be able to perform as required, it is crucial that their integrity is ensured and maintained. In a number of compartmented areas, openings may be required to allow access and egress from the area and to provide services such as electrical and communications cabling, ventilation systems and so on.

In order to ensure the integrity of the fire compartment, it is critical that every opening through its walls, floor and ceiling, from large openings such as doorways to the smaller service penetrations (wiring, piping and ducts), be adequately protected to resist the passage of fire and smoke. This may include:

  • installing fire-resisting door-sets with appropriate self-closing devices

  • the provision of fire-stopping in cavities such as vertical shafts, ducting for cables, roof spaces and voids behind panels

  • installing dampers in air extraction or ventilation systems

  • installing fire-resistant glazing.

Failure of compartmentation

For a fire compartment to be effective, it must totally separate an area from the remainder of the building by continuous fire-proof construction. It can be the case that the effectiveness of compartmentation is compromised by uncontrolled or poor works by contractors.

All construction products used for compartmentation purposes must be tested to the appropriate standard (eg BS 476 Fire Tests on Building Materials and Structures or BS EN 1363 Fire Resistance Tests). However, a product is only as good as its initial installation and ongoing integrity. Early failure of a compartment may occur due to one or more of the following.

  • Poor workmanship during installation of the fire-resisting element at initial build or refurbishment.

  • Use of inappropriate materials/elements for passive fire-protection purposes at initial build or refurbishment.

  • Removal of all substrate, leaving excessive penetrations with no fire stopping (eg during installation of new cabling).

  • Poor replacement of elements or use of inappropriate products following direct repairs or alterations to those elements.

  • Damage/removal of elements during indirect repairs or alteration works on the premises.

  • Damage to elements during maintenance and/or inspection of that element.

Many of these potential failures can be associated with those undertaking in-house activities, but many of the activities that can lead to the potential failures are likely to be undertaken by contractors. This can create issues as to the control of the works and assurance of continued integrity of passive fire-protection elements. As the Building Research Establishment notes: “a main contractor will often use various sub-contractors to complete a project…many of whom will not have been trained in the importance of passive fire protection and in its correct installation”.

A major issue raised by this is that, often, many different products are used, some of which may not have been independently fire-tested and others that have been fitted by inexperienced and untrained installers.

In addition, BS 9999:2017 Fire Safety in the Design, Management and Use of Buildings. Code of Practice notes that where there are a variety of different trades working on a building, there might be serious interference by a later tradesperson on passive fire-protection measures already installed.

Control of contractors

For those with fire safety responsibilities, there are two issues to be considered.

  1. The control of contractors who are installing, maintaining, repairing, replacing or upgrading passive fire-protection elements used for compartmentation.

  2. The control of contractors who may be undertaking work that could indirectly impact on the integrity of current passive elements or that introduces additional compartmentation requirements (eg installing new cable ducting).

PFP products should be fit for purpose, properly installed and maintained in accordance with the manufacturer’s instructions or a relevant standard. As noted by the Association for Specialist Fire Protection (ASFP): “Third-party certification schemes for such products and installers are an effective means of providing the fullest possible assurances.” As such, when using the services of contractors to maintain passive elements, certification and/or membership to appropriate third parties should form part of the overall selection process. Certification schemes include Certifire, BRE Certification and Loss Prevention Council Certification.

In respect of the second issue, the potential impact of contractors' activities on PFP elements and subsequent compartmentation should be identified in the risk assessment procedure. The assessment can be undertaken along with the contractors themselves.

The appropriate control measures required can then be identified and implemented. These could include:

  • setting the necessary standards required for new passive elements or ensuring remedial works replace like-for-like elements

  • ensuring that competent contractors/subcontractors undertake any remedial work involving existing or new passive elements

  • using a permit-to-work scheme to ensure works are undertaken to strict guidelines

  • the inspection and assessment of the quality of the workmanship during, and following completion of, the works.

Finally, the person(s) undertaking any inspection of works and continued integrity of PFP measures must have an understanding of such elements and their correct installation. The ASFP Guide to Inspecting Passive Fire Protection for Fire Risk Assessors is useful in this regard.