Article by Tom Gregory, Chiltern International Fire, published in TRADA Timber Industry Yearbook 2002.
Fire doors save lives and properties and as such it is vital that they perform the task for which they were intended. There are a number of opportunities for mistakes in the process from fire door design to end-use.
Once a fire door has been designed the manufacturer needs to prove its performance. UK Building Regulations, through their associated guidance - Approved Documents, Technical Standards and Technical Booklets - require fire doors to have appropriate test evidence from a UKAS accredited test laboratory. In the UK, doors are currently tested according to BS 476: Part 22: 1997. The standard outlines testing and monitoring procedures, including a prescribed time-temperature curve that requires temperatures in the test furnace to exceed 800oC after only 23 minutes. Failure is measured against a number of integrity criteria:
Continuous flaming on the unexposed face for more than 10 seconds
Ignition of a cotton pad held against the unexposed face
Expansion of gaps to allow a gauge of certain size to pass through.
The nature and time of failure are detailed in the test report. It is important to check the details carefully to ensure that the failure time exceeds that which is required by the building regulations guidance and by controlling authorities.
Experience teaches us that the performance of fire doors is influenced by a wide range of factors, including: leaf size and thickness, configuration (double or single acting and double or single leaf), glazing area. Based on calculated principles it is possible for our consultants to assess fire door designs based on existing evidence eg a similar construction of smaller leaf size and reduced glazing area can be covered under an assessment without the requirement for further testing. Relevant assessment evidence from other UKAS accredited laboratories is also acceptable.
A new European test standard has also been recently published (BS EN 1634-1-2000) with the aim of harmonising test procedures and standards throughout Europe. A supplement to Approved Document B for England and Wales produced by the DTLR to explain how this might affect the requirements is in preparation. This will take into account a research project undertaken by Chiltern Fire to establish the crucial factors influencing the performance of doorsets when changing to the BS EN test and providing some guidance on design changes necessary to re-instate the performance.
For those wishing to have a better understanding of fire resistance testing, Chiltern Fire has produced a short video to explain the procedure and evidence. Chiltern also organise training days to explain all aspects of fire door manufacture, testing, certification, installation and specification. The day includes a full-scale fire test to illustrate the impact of seemingly minor flaws in design, manufacture and installation. Please contact Tom Gregory for full details on 01494 569812.
Test evidence is a vital tool in ensuring fire doors are specified correctly, it proves the design can work – assuming it has been manufactured and installed as per the test specimen.
Product certification goes one stage further than testing alone. It provides the confidence that the fire doors arriving on site meet the same high standards as those originally tested. The BM TRADA Q-Mark fire door scheme requires its members to have test evidence for their certified ranges, the production of which must be covered by a Quality Management System, eg ISO 9000. Further still, manufactured doorsets are taken at regular intervals for audit testing to ensure the consistent manufacturing process continues to produce doors meeting the test requirements.
The majority of members are bespoke manufacturers able to offer specifically designed solutions to satisfy a wide range of technical and aesthetic requirements. The BM TRADA website (www.bmtrada.com) lists all the scheme members (almost 40) and gives details of their location and scope of certification, as such it offers an excellent specification list for construction projects nation-wide.
For complete peace of mind it is important to ensure that installation has been carried out as per the manufacturers instructions. Modifications and mistakes made on site can seriously affect the performance of fire doors, even those with comprehensive test and certification evidence.
Checks made on site after installation, unless by experienced consultants, are insufficient to pick up on the majority of errors. To ensure correct installation BM TRADA operate a Q-Mark registered installer scheme which certifies and audits the training and checking procedures of responsible personnel, such as the foreman, on site.
Requiring fire doors to be supplied and installed by Q-mark members means assured and hassle-free specification. Q-Mark members are required to mark fire door leaves, doorsets and installed doorsets with appropriately coloured plastic plugs in the door edge. The colours allow specifiers and controlling authorities to identify the period of fire resistance and status of intumescent, glazing, frame, hanging and installation. The validity of claims can be checked against the details on the BM TRADA website or full details are available on demand from members, summarised as a ‘Scope of Certification’ document or the complete test evidence.
