Divide and conquer

WITH FIRE safety increasingly becoming a key consideration when talk turns towards the design of any commercial building in this day and age, and also as a direct result of several high-profile news stories, the attention being afforded to fire risk, its corresponding mitigation measures and protection regimes has certainly been ramped up of late.

Best Practice for ensuring that today’s buildings are fire-safe, both through fire-resistant construction or appropriate installed fire protection, is to use third party certificated products and contractors. When specifying a product or a given system, such as an external cladding solution or a fire curtain barrier, it’s absolutely essential to verify that it meets the requirements of the appropriate fire test procedures and that it’s suitable for the intended application. Third party product certification provides confidence that the product is fit for purpose and will deliver on the required fire performance.

Certification procedures are conducted by independent bodies accredited by a national notified body. These certification bodies can verify the quality of the product. In practice, samples are chosen at random from a suppliers’ manufacturing facility and tested by a nationally recognised and accredited testing laboratory to an appropriate British, European, ISO or US standard.

As well as checking the product, third party certification includes an initial factory inspection followed by routine surveillance visits to audit factory production control procedures and an evaluation of quality management systems to ensure consistency of production. Once certified, products are placed on a register and labelled such that they are fully traceable and linked to the certification body. Test or assessment evidence of performance can be checked and reviewed, so too the scope of application for each product.

Third party installer certification provides confidence that the product will be installed professionally by a contractor who has the required expertise, skill and commitment for the task at hand. Third party certificated contractors use trained members of staff whose competence has been evaluated, whose records are open to audit by the certification body and whose work is subject to random checking by qualified inspectors.

For their part, third party certificated installers will issue a Certificate of Conformity for completed work and label all installed products so as to provide an audit trail.

Third party certification

For the fire curtain industry, BS 8524: Active Fire Curtain Barrier Assemblies – Specification is an important standard, providing comprehensive guidance on specification and installation procedures. Under BS 8524 Parts 1 and 2, only third party certified fire curtain products are granted compliance, while the third party assessing body appointed by the manufacturer must hold a UKAS accreditation.

Aimed at designers, specifiers, manufacturers, installers and facilities managers alike, the British Standard covers key aspects such as the proficient installation and ongoing maintenance of the fire barrier (which must be achieved to illustrate competence and quality). This certification offers assurance to end users and building occupiers that the product has been subject to – and subsequently passed – thorough third party testing against a set of rigorous criteria.

The current British Standard superseded the former fire curtain specification, namely PAS 121:2007, back in April 2013. Drawing upon the previous standard in place, BS 8524 covers the whole system and the process of installing and servicing these life-saving products.

For full compliance against the British Standard, fire curtains must have passed all of the necessary tests. If one or more of these tests are not completed then the product is not considered to have reached the minimum requirements necessary to gain this seal of approval.

BS 8524 is segmented into two parts. Part 1, the specification for active fire curtain barriers, provides information, requirements and guidance on how to test for each aspect of the British Standard. It can only be achieved if all nine annexes are satisfied and approved by a third party certification body. Annex G, for example, outlines the testing method for motor operation which involves placing it at elevated temperatures and at maximum loads following a prescribed timeline heat curve for a specified number of cycles.

Part 2 delivers a Code of Practice for the application, installation and ongoing maintenance of fire curtains. The annexes of which it consists include guidance on installation checklists, commissioning and maintenance requirements. For example, the comprehensive Inspection Checklist in Annex F details the requirement for the curtain to descend into a ‘closed’ position at the descent speed when the power to the control panel is disconnected. This proves the gravity fail-safe mechanism is functioning correctly and is able to maintain the required descent speed as dictated by the British Standard.

Compartmentation issues

The integration of fire-resistant barriers, such as fire doors and curtains, into a building’s design divides an open space into compartments. In large-scale commercial premises, for example, there are often multiple challenges when it comes to building compartmentation and passive fire protection. With the rise in popularity of open-plan layouts, it has become increasingly impossible to use fire doors due to the lack of walls. Where fire doors cannot be implemented, fire curtains may be installed.

Stored discretely in a steel headbox located above a ceiling, lobby or doorway, a fire curtain is a highly robust piece of fire-resistant material. In the event of a fire, the curtain is released by a signal from a fire alarm or local detector, which then allows it to fall vertically via gravity, duly obscuring the space, doorway or lift shaft above which it’s located. Once deployed, the role of a fire curtain is crucial for the prevention of flames spreading either laterally or vertically, acting as a physical barrier between the fire and the escape routes to be used by occupants in order to evacuate the premises.

Unlike fire doors, fire curtains can be installed in a number of different locations including where there’s a lack of walls, such as in the aforementioned open-plan spaces. A fire curtain can be used to replace a non-load bearing wall and fire-rated glazing, for example, which in turn allows open-plan building designs to meet the relevant regulations.

Fire-resistant curtains and doors serve three main purposes in a building: to limit the initial development of a fire, prevent the spread of fire and protect escape routes. A correctly installed fire curtain can help to suppress the growth and development of fire and smoke within a given building.

The Building Regulations require escape routes to be protected. Any opening, such as a doorway, that doesn’t make use of fire-resistant barriers poses the risk of fire spreading into designated escape routes. Therefore, fire curtains are used to protect building occupants when the time comes to evacuate.

With the help of certification and testing, a fire barrier is designed to withstand the heat and effects of a fire for a specific period of time. That period is specified to enable an effective and efficient evacuation with enough time to make the necessary checks of the building in order to minimise the degree of risk posed to human life.

Level of integrity

The fire resistance and integrity of components used in building construction has necessarily come under increased scrutiny in recent times. In turn, this has placed a higher degree of focus on the level of integrity of every product. In relation to the fire resistance test for curtains and other fire barriers, the UK testing certification is BS EN 1634-1. This actively investigates how a fire curtain maintains its integrity when exposed to fire. The level of integrity illustrates a product’s fire resistance level.

A highly effective alternative to fire doors is the use of fire curtains as they can offer the same levels of fire resistance and smoke control. Fire curtains can be set within the ceiling and walls or face-fixed depending on the building requirements. They will then sit discretely in place, remaining hidden, yet always ready for deployment when needed in a fire situation due to their gravity fail-to-safe operations, even when all areas of power are not available for consumption.

In operation, fire curtains work to decrease levels of smoke and fire before they can spread further throughout a section of the building. They are typically lightweight and rarely need additional support when being installed, meaning that the inclusion of a fire curtain infrequently alters the design of a building.

Incorporating fire curtains within a building’s design separates an open space into individual compartments. Given the increasing rise in popularity of open-plan layouts for buildings, it has become increasingly difficult – if not impossible – to incorporate fire doors where there’s a lack of wall space. Conveniently, fire curtains can be installed in almost any position.

Indeed, fire curtains have minimal limitations when it comes to their installation. A fire curtain can be used to allow open-plan building designs to still meet fire safety-focused regulations. Areas where there are stairs, lifts or lobbies, and which are arguably the most critical escape routes, can benefit from the deployment of fire curtains to help control smoke and prevent it from spreading through the stairwells and lift shafts.

With the support of intricate testing, a fire curtain is designed to withstand the heat and effects of a fire for longer periods.

Freedom of design

Fire and smoke curtain barriers allow for a greater freedom of building design, while in parallel ensuring minimal visual impact. This permits designers to be more radical with building design by increasing usable space.

When used as part of a fire-engineered design solution, barrier assemblies can become a critical element of that design. If barrier assemblies do not deploy to their operational position, the fire-engineered design solution would be compromised.

However, in the event that other fire protection systems or elements don’t function – due to total power failure, for example – then the barriers in the fire-operational position provide effective fire separation.

David Keeble is Head of UK Sales at Coopers Fire (www.coopersfire.com)