Feature

Fire Safety

Assessing the risk in complex buildings

Fire safety

It can be argued that the subject of risk management in complex buildings is probably beyond the competence of the average fire risk assessor. While this is possibly a controversial observation to make, especially at the start of an article on risk management in complex buildings, as more problems with fire risk assessments arise and become widely reported in the press, it is increasingly becoming accepted opinion.

It is well known that under the Regulatory Reform (Fire Safety) Order, there are currently no qualification, knowledge or experience requirements for fire risk assessors. Anybody can do it and as a result there are a number of substandard risk assessments in circulation.  The more infamous assessments (e.g. those for Lakanal House) have been well documented, but what about more complex buildings such as fire engineered buildings? What special requirements do they have that make them ‘beyond the competence of the average fire risk assessor?’

FIRE ENGINEERED BUILDINGS
Fire engineered buildings are complex and offer a lot of advantages to the building owner, the occupier and the developer/contractor, such as:
•    Innovative design
•    Extended escape distances
•    Reduced fire resistance periods for the structure
•    Increased compartment sizes
•    Removal of stairs resulting in an increase in the useable floor plate
•    Flexibility in the use of space for the end user
•    Reduced construction costs.

To enable this, fire engineered buildings are reliant upon a number of engineering techniques such as hot smoke extraction systems, smoke venting, smoke curtains, extensive automatic fire detection, fire suppression systems, compartmentation of high risk areas and well defined operational procedures.

Such an approach demands a high standard of fire safety management covering the day-to-day operational arrangements for the building; for example, the maintenance of low fire loads and/or sterile areas in foyers or large circulation spaces. It also requires a robust planned preventative maintenance regime in respect of fire safety systems. Whilst this is feasible, is it realistic in the day-to-day running of buildings? What happens over time when, bit by bit, small changes are made to the building which compromise or invalidate the fire safety measures which are essential to a fire engineered building working correctly? This in turn raises another fundamental question, what happens if the building should come under significant terrorist attack by way of an explosive detonation either to the external fabric of the building or within its internal structure? 

THE RESPONSIBLE PERSON

The fire risk assessor evaluating a complex building will need to review the Fire Safety Strategy (FSS) in order to be able to undertake a ‘suitable and sufficient’ assessment. Whilst fundamentally accepting its validity, since it will have been signed off by the regulator, the assessor will need to review the FSS for deviations present in the building which will need addressing; either by requiring compliance or developing an alternative strategy. It should be noted that the FSS will often be justified by detailed models and calculations which are outside the scope of a fire risk assessment. They are also likely to be outside the competence of any fire risk assessor who is not a fire engineer.

In order to undertake the fire risk assessment, the assessor will also need extensive support from the ‘Responsible Person’ because he/she must hold all the information on all the fire safety systems that make the building safe. This will include all the passive fire protection (structural or built-in) measures, all the active fire protection (detection, alarm, suppression) measures and for complex buildings, the Fire Safety Strategy including the assumptions made in producing it.

For buildings built since 2006, the requirement to maintain such information is enshrined in regulation 16b of the Building Regulations. This requires that information be given to the Responsible Person so that any fire risk assessor can obtain the information from them and undertake their fire risk assessment. Unfortunately, 16b information is rarely available which makes it more difficult for the Responsible Person and the fire risk assessor to come up with a credible fire risk assessment.

There are four areas that the fire risk assessor will need to concentrate on in conducting a fire risk assessment on a complex building based on the a review of the Fire Safety Strategy. These are now considered in detail.

REVIEW OF BUILDING GEOMETRY

Has the building layout or geometry been changed from that specified in the Fire Safety Strategy? In particular, has the building been modified? Does the compartmentation and use of the building reflect what is stated in the strategy?

In undertaking his/her assessment, the assessor will need to review any modifications to the building or maintenance that could have compromised the compartmentation.   He/she will need to determine if there is a record of such works and the action taken to ensure that compartmentation has been maintained. For example, is there a certificate of conformity from a specialist passive fire protection contractor, or did the responsible person undertaken his/her own inspection to verify adequacy?

The obvious item to look at in any fire risk assessment of passive fire protection is the condition and operation of fire doors as they are readily accessible. Unfortunately fire travels in difficult to access areas and in concealed spaces and cavities. That’s why there is so much guidance in AD-B on fire stopping and subdividing large concealed spaces. Consequently, other questions that will need answering are:
•    Have new services been installed e.g. above suspended ceilings that penetrate fire compartment walls/floors?
•    Has the compartmentation been made good following installation?
•    Have penetration sealing systems been modified or removed?
•    Are fire dampers in situ as required?
•    Are the fire dampers accessible for inspection and/or testing by the local authorities? If fire dampers are not accessible from a grill, an access door in the ductwork is required.
•    Has the operation of fire dampers been compromised by lagging to ducting or other obstruction of the moving parts, or where applicable, the fusible link?
•    Are the dampers maintained and checked at least annually? (Annex W of BS9999 gives guidance on maintenance of fire resisting         ducts and fire dampers).

REVIEW OF FIRE SAFETY SYSTEMS
In the same way that all the passive fire protection measures need reviewing, so do the active fire protection measures. Consider the fire safety systems listed below and ask yourself if the average Responsible Person or fire risk assessor can answer the questions related to each.
•    Fire alarm including automatic fire detection
•    Smoke and heat extract ventilation systems (SHEVS)
•    Smoke control pressurisation systems
•    Fire Suppression systems e.g. sprinklers, water mist and gas suppression systems
•    Evacuation lifts/fire-fighters lifts

OPERATIONAL ARRANGEMENTS
Operational arrangements covering the management and operation of the building will need to be reviewed as part of any fire risk assessment, specifically to ensure it is in alignment with the Fire Safety Strategy. In doing this the fire risk assessor will have to use his skills and experience to address the following areas: means of escape, control of fire load, displays and temporary furnishings, and housekeeping and the removal of waste. Looking first at means of escape, the risk assessor will need to ask the following:
•    Has the use and occupation of the building changed from that recorded in the Fire Safety Strategy? Consideration needs to be given to the number of people in the building and their distribution
•    Is the fire alarm protocol unchanged, for example, supporting a simultaneous, phased, or horizontal evacuation?
•    Are all the means of escape designated in the Fire Safety Strategy still available? Consideration needs to be given to potential obstructions, checking compartmentation and fire safety systems
•    Is the resource in terms of personnel adequate to support the evacuation strategy?
•    Are personnel adequately trained and instructed?
•    Are personnel shift changes, work rotas and leave adequately catered for?
•    Is adequate equipment provided?

Increased compartment sizes and extended travel distances, often based around a fire engineered solution that requires atrium, balcony and gallery spaces, need to be kept to agreed fire loads complying with the fire safety strategy. Smoke extraction capability is usually also based upon agreed fire sizes and fire loads (typically found in PD 7974) and agreed with the regulator. Management of the fire load is therefore critical to the performance of the systems specified in the FSS, more so than in a building of prescriptive design and consequently, the assessor will need to verify that it has been controlled adequately.

Displays are often located in corridors, entrance foyers and shop floors, and often comprise materials which provide a means for the rapid spread of fire. The risk assessor should assess how these materials could contribute to the development of a fire.  Possible control measures include:
•    Avoiding the use of displays in corridors and foyer
•    Minimising the size and number of display areas to discrete, separated areas
•    Treating displays with flame retardants and/or using display boxes
•    Keeping displays away from curtains.
Good housekeeping will lower the chances of a fire starting, so the accumulation of combustible materials in premises should be monitored carefully. It is essential to reduce the chances of escape routes and fire doors being blocked or obstructed. Waste material should be kept in suitable containers prior to removal from the premises. Considerable quantities of combustible waste material need to be managed by the development of a formal plan.

PLANNED PREVENTATIVE MAINTENANCE
Planned preventative maintenance and the testing of fire safety equipment essential to the Fire Safety Strategy is crucially important in a complex building because the operation of the systems is critical in affording the required level of safety to the occupants.

The greater variety of systems in complex fire engineered buildings, such as smoke extraction and pressurisation systems require detailed PPM programmes. Complex ‘cause and effect’ matrices are often linked to the automatic fire detection. Changes to the building, its usage, or the procedures, may render these inappropriate. Consequently, systems of scheduling PPM and record keeping are very important in ensuring the relevant systems are maintained in working order. The fire risk assessor will need to investigate these as part of his risk assessment.

CONCLUSION
This article highlights the many special factors that need to be considered in undertaking a fire risk assessment in a complex fire engineered building. There are a myriad of specialist questions under each of the four areas of: passive fire protection, active fire protection, operational requirements and planned preventative maintenance that need detailed answers. Undertaking such a risk assessment is not for the feint hearted and can probably only be undertaken by a qualified fire safety engineer.

Simpler buildings also need qualified and experienced people (although to a lower level) to undertake fire risk assessments.   Consequently the ASFP fully supports efforts being made by the fire risk assessor industry to develop a set of agreed competencies, experience and qualifications in preparation for a national register of fire risk assessors.

The ASFP, in line with its policy promoting third party certification for the manufacture and installation of passive fire protection products, supports those schemes which require full third party certification, either for individual assessors under a personnel certification scheme, or for companies who employ assessors under a company scheme. Any such schemes will need to be accredited by UKAS – the UK body responsible for accrediting certification bodies – to ensure credibility. It is only in this way will we see the status of the profession of fire risk assessor rise to the level that it deserves.

 



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