Timber Fire Door Test Result

The Ministry of Housing, Communities & Local Government (MHCLG), on 18th July 2019, finally issued a long expected short summary note of the results of the tests they initiated on timber fire doors on the advice of their Expert Panel (as part of the overall response to re-establish confidence after the Grenfell fire).

It’s all GOOD NEWS! Though no surprise at all to the specialist door sector.

Timber fire doors rated for 30 minutes fire resistance from 25 suppliers were tested in a standard furnace test of the type that has been carried out by door manufacturers many hundreds of times over the years. A total of 50 separate tests are recorded in the Ministry note, carried out from 15.10.18 to 16.03.19.

We now have the formal reporting of the results. All doors passed, very well. For the early tests the Ministry asked for testing to be terminated at 36 minutes. For the subsequent tests the test duration was extended to onset of integrity failure in accordance with the standard test criteria. Many of the doors succeeded in going beyond 35 minutes, some even going successfully beyond 50 minutes.

The results point to three main conclusions that should emphasise a high degree of confidence in timber fire doors:

a) High level confirmation of the performance of timber fire doors: no failures at all; and typically a significant safety margin test overrun for a number of doors.

b) Consistency of performance, from one supplier to another across the sector.

c) Confirmation of the established test convention for timber fire doors for the door to be tested in what is deemed to be the weaker leaf opening direction, into the furnace.

It is particularly important to note that the convention of testing timber fire doors with the leaf opening into the test furnace for symmetric door leaf constructions is suitably supported by the tests. That is a well-established rule, derived from testing over the years across the sector, in combination with an established understanding of the door technology in fire. The convention is supported by UK test houses in the testing they carry out. And is confirmed in the clauses of test standard BS EN 1634-1, based on a Europe-wide consensus as part of the EN standards process, as well as by BS 476 as a test principle.

ASDMA’s advice for timber fire doors remains as it has always been. That is for doors to be properly supported in-depth by a continuous process of both formal and research & development testing established over several years. Testing is carried out across the sector, not only by door manufacturers but also by main door component and door blank providers as well. There is, in effect, a tremendous multiplication of testing across the specialist timber door sector. That in-depth understanding of the door technology within the sector should be taken by specifiers, clients and authorities alike to provide a justified high level of confidence in the specialist door sector. Testing is a way of life.

Appropriate test evidence can be found in individual test reports and better from technical assessment evaluations which take into account a number of relevant and appropriate test reports that go together to define the scope of design and application. In addition, manufacturers should also be covered by third-party product certification, which includes regular review and auditing of product consistency, testing and factory control processes linked with overview of quality systems.


What is passive fire protection?

As its name suggests, passive fire protection (PFP) is a form of fire safety provision that remains dormant, or inert, during normal conditions but becomes active in a fire situation. It is an integral component of structural fire protection in a building, which is designed to contain fires or slow their spread. The purpose of PFP is to contain the spread of fire for sufficient time to permit i) the safe evacuation of all occupants of the premises and ii) the arrival of the fire brigade. The person responsible for fire safety also has a duty of care towards any members of the emergency services, e.g. fire fighters, who may have to enter the premises during the course of a fire; in slowing the spread of flames, smoke and hot gases, PFP also serves to ensure the building remains as safe as possible for entry in this situation.

PFP: what and where?

PFP provision is required in all buildings, whether domestic or non-domestic, with the purpose of containing / compartmentalising / retarding the spread of fire.

There are several methods and products available that will achieve the required standard of fire resistance in existing buildings, some of which may be more appropriate than others. If you have any doubts about the best way to ensure PFP provision in your premises, you should seek the advice of a competent person. Any new build / modernisation / extension works must be carried out in accordance with The Building Regulations 2010, Fire Safety, Approved Document B.

In respect of internal fire spread (structure) and the relevance of PFP in particular The Building Regulations 2010 (Volume 2, p 67) stipulate the following (Requirement B3):

  • Where reasonably necessary to inhibit the spread of fire within the building, measures shall be taken, to an extent appropriate to the size and intended use of the building, comprising either or both of the following –

(a)    sub-division of the building with fire-resisting construction;

(b)   installation of suitable automatic fire suppression systems.

  • The building shall be designed and constructed so that the unseen spread of fire and smoke within concealed spaces in its structure and fabric is inhibited.

In respect of the protection of openings and fire-stopping in order to inhibit the spread of fire, 10.2 of the Regulations states (p 85):

If a fire-separating element is to be effective, every joint or imperfection of fit, or opening to allow services to pass through the element, should be adequately protected by sealing or fire-stopping so that the fire resistance of the element is not impaired.

There are two main types of opening that could compromise the integrity of a fire resistant structure: openings for pipes (10.5); and ventilation ducts, flues, etc. (10.9). At 10.17, additional provisions in respect of fire-stopping are detailed as follows:

  1. joints between fire-separating elements should be fire-stopped;
  2. all openings for pipes, ducts, conduits or cables to pass through any part of a fire-separating element should be:
  1. a) kept as few in number as possible; and
  2. b) kept as small as practicable; and
  3. c) fire-stopped (which, in the case of a pipe or duct, should allow thermal  movement).

Every service that is installed in a building, such as water pipes, electrical sockets, cable trunking and lighting units, can compromise the fire resistance of a room by creating openings in its walls, floor and ceiling. The role of PFP is to seal the gaps these penetrations create should the worst happen and fire break out. All products designed to fulfil this criteria are fire rated, i.e. certified to resist fire for a specified length of time, which can be anything from 30 minutes to 4 hours. They all include an intumescent material, which remains dormant, or passive, during normal conditions but swells to many times its original size when exposed to the heat of a blaze.

Examples of PFP

Fire doors, whose purpose is to contain a fire / protect a designated fire escape route, should be fitted with intumescent fire and smoke seals, either around the edges of the door leaf or the frame. These seals are an integral part of a fire door structure and ensure that, not only is the spread of fire prevented, but also and more importantly the ingress of cold smoke in the early stages of a fire. Smoke is known as the silent killer as it can overwhelm the occupants of an enclosed area long before the heat and flames of a fire are sensed.

The hot gases of a blaze can also move swiftly around a building, undetected at first, for example through air conditioning ducts. Intumescent air transfer grilles, which are typically 30 or 60 minute fire rated, allow air to circulate freely around a building under normal conditions, but the intumescent material swells and creates a barrier to restrict the passage of hot gases in a fire situation. They are suitable for use with both fire rated doors and compartment walls.

Intumescent pipe wraps and collars are designed for use on plastic pipes that pass through masonry floors and walls; the intumescent material expands inwards in a fire situation to squeeze the collapsing pipe until the opening is completely sealed.

Intumescent downlighter covers and fire hoods / canopies for recessed light fittings prevent fire from penetrating the ceiling void and thus preserve the fire resistant integrity of the ceiling; they are typically 30 or 60 minutes fire rated.

Electrical sockets in walls and skirting boards are another vulnerable point in a fire rated compartment; intumescent socket box inserts / covers expand to fill the electrical box in a fire, preventing the spread of flames, smoke and hot gases.