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Tuesday 15th September 2009
BS9999 has been heralded as a practical guide for fire safety, offering additional flexibility in design and management. However, care is needed in its application
by James Lane
17 September 2009
Widely recognised as the de facto industry standard, the Approved Document B (ADB), with additional reference to the British Standard BS5588, has been the mainstay in assessing buildings for fire safety compliance for many years.
While adoption of the ADB is not mandatory, departure from its recommendations would normally mean negotiation with Building Control and the local Fire Service.
Rather than diving straight into a fully fire-engineered solution, it might be that a simple case of providing a compensating measure to offset a small departure from the code is all that is required.
Although a well-practised tool, assessment under the ADB is far from an exact science. With allowances in relation to compensating features typically agreed on a case by case basis, this has led to significant variations in practice, according to the viewpoint of the individuals involved.
The new BS9999 is not intended to be a fire engineering standard. Its aim is to offer a more structured approach for assessing fire safety requirements based on risk rather than the more general ADB, but which are not complex enough to warrant a fully engineered fire solution.
By outlining a sliding scale of extended limits for appropriate enhancements being considered over the minimum provisions, BS9999 has effectively formalised the trade-off process, helping to ensure greater consistency in its enforcement.
How it works
The basis of the new code is the assignment of a risk profile to each building. Measurement is based on a combination of occupancy type (defined according to alertness and level of familiarity) with the building's potential rating for fire growth (from 1 'slow' to 3 'fast'). Different categories of buildings may attract similar profiles.
A base case is then established for the assigned profile, taking into account maximum travel distance and minimum exit and stair widths, with the assumption that no additional precautions will be present. Any enhancements over the base model are assessed in line with a sliding scale of appropriate benefits.
In a building project where many additional features will be introduced, the benefits may be aggregated to provide greater flexibility in the restrictions for travel distances and widths, up to a specified maximum limit. A building's overall risk profile may also be reduced through the addition of measures such as sprinklers, the contribution of which to fire protection is recognised for the first time under the new code.
How will it affect me?
During the lifetime of a building, changes in usage are inevitable, either in ownership and tenancy or shifts in the resident population, often resulting in material site alterations. This may prompt a re-evaluation of fire systems and equipment, where such changes mean provisions are no longer in line with the assumptions made when developing the original fire strategy. BS9999 potentially offers increased flexibility in gaining acceptance from Building Control/fire officers for variations intended to bring systems up to date.
The clarity of the BS9999 approach will assist facilities managers as non-specialists in interacting with architects and fire safety consultants to evaluate and influence system specifications by providing a common basis of understanding.
In addition to providing a valuable benchmark tool for assessment, the new code also offers comprehensive guidance to assist facilities managers in determining the level of ongoing management appropriate to the building's risk profile.
In particular, the code presents requirements of the Regulatory Reform (Fire Safety) Order and the introduction of regulation 16B to the Building Regulations. These requirements call for all relevant information for fire safety to be passed on to the designated 'responsible' person, ensuring any important features are recorded.
This practice is an excellent safety development, ensuring that future changes to the building will not compromise the existing fire strategy.
Where next?
The current climate, with a slowdown in new building works, means that the full benefit of BS9999 has yet to be realised. Where decisions are taken in-house for budget reasons, it is important to recognise that the BS9999 code of practice can only work where recommendations are universally adopted. Convenient use of only those parts that offer a benefit to the building in question, reverting to the ADB for other areas, could lead to a serious failure in the co-ordinated fire safety package for a development.
Understanding the limits of the new code, and where it is appropriate for it to be used in place of the ADB, and at which point a bespoke fire-engineered solution should be commissioned is something best left to the experts. The safety of buildings, and the people that use them, is not an area where risks can, or should, be taken.
James Lane is principal fire consultant for consulting engineers Hilson Moran
Fire facts
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Serious fires for all types of dwelling cost more than £169 million in the UK in 2006 (Fire Protection Association).
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Fire affects one in every 100 businesses. Many never re-open.
- Blocked cooling vents
- Overloaded electrical system
- Fuel store areas with high oxygen concentration or poor protection
- Materials that produce toxic fumes when heated
- Objects that block fire exits
- Clothes resting under a gas dryer