FOCUS
Protection systems
Compliance and systems
A fire resisting product claiming 30 minutes’ fire resistance performance is therefore capable of 30 minutes’ fire resistance performance to the relevant test standard. Any adjustments to the specification of the product outside of the supporting documentation (eg engineering assessment, field of application or test evidence) could lead to a failure. Of equal importance is the correct installation
of the product: fire resisting construction is only as good as its weakest link, and often it is the installation of fire resisting products that undermines the proven capabilities of the product.
All elements of fire resisting construction must be considered as systems – a complete design constructed in accordance with the supporting evidence of performance for the element of construction. These elements include fire doors; glazed screens; fire stopping materials for service installations; fire rated ducts; dampers; roller shutters; operable fabric curtains; ceiling systems; load bearing walls and floors; dry wall partitions; cladding; fire retardant coatings; structural steel and engineered joists.
Adopting a piecemeal approach to passive
fire protection could, at best, result in a tortuous and potentially expensive sign off process at building handover (assuming it is picked up on); or, at worst, critical life safety systems being installed that are likely to fail in the event of fire. Fire resisting products are only designed to be used once, which is why they need to be right first time. The following are a few examples of fire resisting construction products in which
20 MAY 2018
www.frmjournal.com
the systems approach was not followed, as a result of poor specification, manufacture, installation or ongoing maintenance, and which were subsequently fire tested to the relevant test standard: 1. Incorrect use of expanding polyurethane foam to seal around cable trays. The foam was proven for use as a linear gap seal for four hours’ fire resistance, but when tested around a cable tray to the same temperature and pressure conditions, it provided 12 minutes.
2. Modified toughened glass incorrectly fitted in a glazed screen with incorrect expansion allowance, and with too large edge cover from the glazing beads. Glass capable of 30 minutes’ fire resistance when correctly installed, was subsequently tested to BS 476: Part 22: 1987, and failed within four minutes.
3. A fire rated letter plate proven for 30 minutes in solid timber door construction. The same letter plate, incorrectly fitted within a tubular chipboard core, subsequently failed in 15 minutes when tested to BS 476: Part 22: 1987, as reacting intumescent flowed into the tubes within the core.
4. A 30 minute fire resisting door with head rail removed (leaf adjustment should have been from bottom of leaf only) provided less than 20 minutes when subsequently tested to BS 476: Part 22: 1987.
In the examples cited above, fire resisting products were used, but because they were not compatible or had not been tested as they
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