School design has come a long way over the decades, with architects increasingly utilising large, open-plan and multi-use spaces to provide bright, airy environments from which to teach and promote socialisation.
While contemporary schools require flexible open spaces, achieving this isn’t always straightforward. Building Bulletin 100 (BB100) guidance on the construction, fire safety compliance and ongoing management of educational establishments has long promoted cellular room layouts with limited compartment sizes as a means of containing fire. However, BB100 also acknowledges that where an alternative approach is required, this can be overcome by adopting a fire engineered approach, stating: “It may be the only practical way to achieve a satisfactory standard of fire safety as school building usage becomes ever more flexible in response to the needs of the local community.”
Achieving a similar level of fire safety with larger open spaces puts greater onus on the remaining elements to perform in the event of fire. Fire design is key and should form an integral part of the overall building design. By enlisting experienced fire design engineers at the outset, architects and designers can meet the needs of the end client without excessive cost or design compromise.
A fire engineered approach may enable designers to move away from prescriptive codes that can restrict design freedom in order to maximise space, increase design flexibility, extend travel distances, increase compartment sizes and achieve virtual compartmentation, or avoid costly fire systems.
There are several ways to provide fire engineering solutions within schools, largely through the use of computational fluid dynamics (CFD) analysis, ASET/RSET assessment and risk-based approach.
CFD modelling predicts the flow of gases within a building and is a highly effective way of illustrating smoke movement and combustion products. It takes into account the building’s shape and scope of safety features to predict how smoke would affect the means of escape routes. In addition, through the use of ASET (available safe egress time) and RSET (required safe egress time) assessments, it is possible to calculate the potential evacuation period required to successfully escape from the building and the maximum available escape period which can be determined by CFD analysis.
Building code requirements and insurers can require systems such as property protection sprinklers. Although there is a cost to install these systems, they can bring benefits to the design and reduce fire rated construction. With the use of sprinklers, it is possible to increase compartment spaces from the standard 800sqmup to 2,000sqmand remove the requirement for compartment walls and floors. While in the case of buildings with a top-floor height below 5m, fire resistance periods can be reduced from 60 to 30 minutes on the basis of lower evacuation times and ventilation conditions.
Sprinkler systems can be divided into two categories, ‘life safety standard’ and ‘property protection’ systems. While risk assessment outcomes only call for the use of property protection systems, life safety systems may be required to meet regulations. An appropriate balance can be struck by enhancing certain elements of a property protection system, specific to the educational facility in question, satisfying insurers and building regulations while also providing potential cost savings.
Finally, another important consideration when designing a fire strategy is the ongoing fire safety management of the building. Fire safety and evacuation management must be easily understood and implemented by staff. Fire risk assessment must be completed by suitable and appropriately qualified persons and fire safety systems maintained as required by the Regulatory Reform Order (RRO).
The author of this article, Jigar Pandya, is senior fire engineer at fire engineering consultancy FDS Consult W: www.fdsconsult.com