DESIGN PROCESS
HOSPITALS • Fire – HTM 05-02
FIRE RESISTANCE The requirement for fire resistance will be given in the devolved countries’ regulations and guidance. The period of fire resistance is determined in minutes and measured as integrity (E) and insulation (I). Integrity (E) The through-wall system should stop flames and hot gases from passing through the element for the specified fire resistance period. Failure is deemed to have occurred if flames or hot gases physically pass from one side of the element to the other during the fire resistance period. Insulation (I) Insulation refers to an element or system’s ability to limit the surface temperature rise above ambient on the non-fire side of the element to 140°C as an average, or 180°C as a hot-spot maximum, for the specified fire resistance period during which the fire side is exposed to a fully developed fire. Loadbearing (R) Loadbearing refers to an element or system’s capacity to resist collapse due to loss of structural strength caused by exposure to fire, or more specifically the heat generated by a fire. The element should remain structurally stable for the specified duration. Direction of fire test Because a through-wall system is asymmetrical, the designer should check that the fire test evidence is compliant for the project requirements – inside to out, outside to in. Reaction to fire Reaction to fire relates to the degree to which a product will contribute, by its own decomposition, to a fire under specified conditions. At the time of writing, the devolved regional guidance differed in its acceptance criteria. Classification of products is arrived at by using BS EN 13501-1. These classifications are determined by testing to BS EN 11925 part 2 Reaction to fire
• Acoustic – HTM 08-02 • Energy – HTM 07-02
COMMERCIAL • Fire – AD B Vol 2 • Acoustic – AD E • Conservation of Fuel and power – AD L2A, 2B The table on page 24 captures all the performance requirements for through-wall systems. The system owner is encouraged to publish their performance using the template in this table. Note: air permeability performance is an onsite test that includes windows, doors and air vents; the results will depend on how well these are sealed. The Centre for Window and Cladding Technology (CWCT) publishes guidance on sustainability, design, specification, construction and performance. cwct.co.uk/pages/welcome-to-the-cladding-forum FIRE PERFORMANCE Through-wall infill SFS is a series of components that, when tested together and installed as tested, can provide evidence of fire performance. There should be no substitution of components without the system owner’s written approval. REACTION TO FIRE AND FIRE RESISTANCE Reaction to fire and fire resistance are separate measures of fire performance but there is often confusion between the two. Fire resistance is the measurement of the ability of a system to resist, for the period of required fire performance, the passage of fire and heat from one distinct area to another. Reaction to fire is the measurement of how a material will contribute to the fire development and spread, particularly in the very early stages of a fire, when evacuation is crucial. Reaction to fire is classified under BS EN 13501-1. Fire classification of construction products and building elements - Classification using data from reaction to fire tests.
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