Passive Fire Protection – the effects of the Regulatory Reform (Fire Safety) Order

Chiltern International Fire's Product Assessor Simon Bailey discusses the role of passive fire protection (PFP) products and emphasises the need for correct installation to ensure performance and life safety.

One might imagine that in the midst of a recession, or at best faltering economy, organisations servicing the construction sector would see a downturn in work. In some cases that will undoubtedly be true but for areas related to fire safety legislation the opposite has been the case; there has been a sharp increase in the demand for fire testing, consultancy and training. So much so, in the case of training, that we realised there was a need for a new training course on passive fire protection. It is worth exploring both the background to this demand and the need for better understanding which underlies the new course.

The effects of health and safety legislation can often take years or even decades to become widely apparent. Witness the time for speed limits and seat belts to move from controversy to normality. Inevitably, working in a fire testing laboratory and consultancy we do get an early sense of responses to new fire safety legislation but so often, it is only when people begin to suffer in their pockets that the effects of new legislation really begin to make an impact.

It was well over 10 years ago that the Fire Precautions (Workplace) Regulations introduced the concept of fire risk assessments and began the shift in emphasis from fire protection to fire prevention. Yet it is only in the last three or four years that the 2005 Regulatory Reform (Fire Safety) Order, the RRFSO, has brought this change into a sharper and sometimes more painful focus.

Crucially, in introducing the concept of a Responsible Person for every building other than individual dwellinghouses, the RRFSO has marked, much more clearly than before, the requirement for fire prevention and the very real consequences of failure to adequately discharge that responsibility. The numerous prosecutions brought against individuals and businesses has meant that no one can now afford to ignore their legal duties. Since the legislation began to bite we have seen exemplary fines for breaches of fire safety go up to well over £400,000 for companies and, just last month, to over £150,000 for an individual landlord.

Add into this several very high profile fires such as the Lakanal House fire in a south London tower block, or the Penhallow Hotel fire in Cornwall, and it is then not so surprising that we have experienced an ever increasing number of queries from landlords, councils and contractors, all anxious to make sure that they are fully compliant under the terms of the new legislation. And whilst most people are aware of fire doors (even if they do not always fully understand them), many people, even those with a professional involvement in fire safety, are largely unaware of other, equally important, passive fire protection products such as service penetration seals, cavity barrier seals, or structural protection coatings. It is to increase awareness of the key issues surrounding specification and installation of these products that we have felt the need to introduced our new course and to which I wish to address the rest of this article.

Glazed double door

It has always been the case that the primary aim of fire safety legislation has been life safety. In the UK, the overall aim of Part B of the Building Regulations 2000, which is concerned with fire safety, is to provide building occupants with sufficient means of escape to reach places of safety before the environment becomes life threatening. It consists of five sections, each of which expresses, in very few sentences, general requirements for the following:

• B1 Means of warning and escape
• B2 Internal fire spread (linings)
• B3 Internal fire spread (structure)
• B4 External fire spread
• B5 Access and facilities for the fire service.

The requirement for section B2 for example is, to say the least, succinct:

(1) To inhibit the spread of fire within the building, the internal linings shall:

(a) adequately resist the spread of flame over their surfaces; and
(b) have, if ignited, a rate of heat release or a rate of fire growth, which is reasonable in the circumstances

(2) In this paragraph 'internal linings' mean the materials or products used in lining any partition, wall, ceiling or other internal structure.

Which is fine. To allow the flexibility needed in the real world, they are designed to be functional rather than prescriptive. But of course this also means they are open to interpretation. In B2, for example, what might be deemed 'adequate' or 'reasonable'? To help provide guidance, a series of government approved documents have been written to give practical ways in which to meet these generalised requirements. In the case of fire it is Approved Document B, or ADB as it is generally known, which identifies how to adequately meet the requirements of sections B1 to B5.

Although for larger or more complex buildings there are other ways to meet the requirements of the Building Regulations, such as fire engineering strategies or the guidance given in BS 9999:2008, for most buildings it is ADB which has become the bible against which the adequacy of fire safety measures are judged. It is from this perspective that the key issues will be considered.

As can be seen from their headings, the five sections of the building regulations follow, more or less in sequence, both the response to a fire and the way in which a fire might be expected to develop or be contained. Means of warning is a separate speciality. What we are concerned with here are the ways means of escape can be facilitated by the use of suitable passive fire protection products, as required by sections B2, B3 and B4.

The first characteristic we need to understand is the requirement in section B2 for the linings used in buildings to have appropriate levels of ignitability and spread of flame. The 'reaction to fire' can make a significant contribution to the both the speed of growth of a fire and the rate at which a fire spreads, and lining materials are therefore required to have a specified classification based on fire testing to National or European standards, as shown in the table below. Typically, the linings in common areas of buildings and the external claddings of buildings less than 1 metre apart, will be expected to meet National class 0 or European class B –s3, d2, or better classification.

Table: Reaction to Fire Classes

(The supplementary European classifications, shown as s3 and d2, refer to smoke production and flaming droplets but are beyond the scope of this article.)

Plasterboards, for example, are generally classified as National Class 0 (European Class B) or better, and most untreated timbers with a density in excess of 400kg/m³ will be National Class 3 (European Class D), but there are few generalisations which can be made, and both substrates and air gaps will significantly affect performance. Products will therefore need to be fully tested to establish their classification; manufacturers often undertake substantial development programmes to achieve the desired rating for their products.

Having established suitable materials for both internal linings and external cladding we need to consider the requirements of section B3, Internal fire spread (structure). This section, which deals with the compartmentation of buildings in order to contain a fire at the point of origin, is at the heart of passive fire protection. Indeed, it could be argued that the aim of containing a fire in its place of origin has been at the heart of all fire safety legislation right back to responses to the Great Fire of London in 1666.

The idea is that a building is divided into sections, each of which can contain a fire and thereby maintain the structure of a building, until occupants have reached a place of safety or, in the case of large complex buildings utilising refuges, can be rescued by the fire service. We need to keep in mind that these compartment lines, generally the main walls, floors and ceilings of a building, are themselves the fundamental passive fire protection elements on which passive fire protection products must ultimately rely.

PFPE fire demo

Put simply, passive fire protection products are both the compartment lines themselves or products which maintain the fire resistance of a compartment line where it is breached by necessary services or openings. Such products include: partition walls, whether glazed or not, which are often designed and tested to have a specific passive fire resistance, typically for anything from half and hour to two hours; fire doors which we are all familiar with but which we should always consider as openable sections of a compartment line; and the less visible products such as pipe and cable penetration seals, fire resistant cladding and sprays to structural elements, and cavity barrier seals.

Although fire doors, because they open, are obviously important breaches to the compartment line and therefore need to be specified and installed correctly, it might be more dangerous in many buildings if the hidden products such as penetration seals are missing or poorly fitted. Once a building has been finished, these seals will only ever be properly looked at if a suitable maintenance plan is in operation using a qualified and experienced passive fire technician, at the time of writing a relatively rare situation. However, such seals are often used to maintain resistance where walls are penetrated by pipes, cables and ducts, potentially allowing fire to spread, hidden from view, through perhaps, two or four hour compartment lines and can often represent larger areas than the doors themselves. It's worth remembering that it was this type of hidden fire spread, through voids in the roof, which enabled the disastrous fires at Hampton Court and Windsor Castle to take hold well away from where they originally started. At the Lakanal House fire in south London there was evidence showing that the fire had spread from one floor to another by means of hidden voids.

Clearly we must understand these products so that they can be correctly specified for the required function. Equally, we must ensure that those installing these products have sufficient understanding and training to install them correctly. Installation is a job for skilled specialists who understand the need to follow the manufacturer's instructions to the letter. We are often called out to undertake site surveys where the passive fire seals are either incorrectly specified, incorrectly or poorly fitted, or just missing altogether. All the testing and product development in the world will be useless if the products are fitted by a technician who does not appreciate the importance of what is being done. Steel for example loses half its structural strength at a temperature of 550°C. An incorrectly clad or sealed steel construction joist could collapse with severe consequences for the building.

There are a number of third-party certification schemes for passive fire protection products, of which the BM TRADA Q-Mark scheme for fire doors is a familiar example. We hope our new course will go some way to meeting the need for further training in this area.

The regulations are enforced by local authority Building Control, approved inspectors, fire service inspectors, district surveyors and local housing authorities. However, our belief is that the onus should be on everyone in the supply chain to take responsibility for ensuring fire safety, from the architect/designer and specifier, to the product manufacturer/supplier and main contractor.

Finally, as we discussed earlier, maintenance can easily be overlooked. It is still not widely recognised that maintaining the assessed fire safety measures is a responsibility under the RRFSO. The responsible person should set up an appropriate routine for regular checks as deemed necessary or practical. Over the lifetime of a building new services are often required or redundant ones removed. Without an ongoing maintenance strategy, carried out by qualified personnel, even well installed passive fire protection can, over time, lose its fire resistance performance.

Further information

For an explanation sheet on European Reaction to Fire Classification or other technical information please contact Chiltern International Fire via their website: www.chilternfire.co.uk.

Related NBS information:

Articles:

• Fire safety and heritage buildings
• Fire safety – Approved Document B vs BS 9999
• Making timber frame structures safer

Selected links:

• Fire protection

June 2011

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