Fire Resisting Metal Doors

				Procedure & Guidance
		Fire Resisting Metal Doors
				Ref	- NFG028
Issue/Revision Date	01/05/2010	Review Date	13/05/2015	Version	4.0

Information on Timber Doors can be found in FS-NFG003 – Fire Resisting Self Closing Doors

Introduction
This Note provides guidance concerning the testing and assessment of fire resisting metal doorsets (e.g. doors with swinging leaves).

Typically a door which is required to satisfy the building regulations for the particular period of fire resistance referred to in the Approved Document is usually subject to a test in accordance with the relevant clause of BS 476: Part 22: 1987.

The test must be performed on a specimen of the complete door assembly and its performance reported in terms of integrity and insulation for a period of minutes. However, insulation is not currently a requirement of the building regulations and additional performance requirements may be specified by insurance bodies and other organisations.

The performance of fire resisting metal doorsets should be covered by:

Product Conformity Certification

Whilst not currently a requirement of the building regulations, product conformity certification of a metal fire door product is available through independent bodies such as LPCB and CERTIFIRE. Certification defines the field of application of the product, i.e. variations in size, mode of action, hardware etc. that will achieve the specified fire performance.

Fire Test Reports

These are issued by UKAS accredited test laboratories to report the performance, in terms of integrity and insulation in minutes of a specific size and combination of frame, door construction and hardware when tested to the relevant clause of BS 476: Part 22. Fire test reports that are quite lengthy documents are limited to the performance of the exact specimen test assembly and contain confidential design data. For this reason manufacturers are often reluctant to release test reports in full.

Assessment Reports

These are prepared under the guidelines of the UK Fire Test Study Group by UKAS accredited laboratories, or suitably qualified independent fire engineers with laboratory test experience of the performance of metal doors. Assessment reports normally take into account evidence from a number of fire tests sponsored by a particular manufacturer in arriving at an assessed performance for a range of doorset sizes, construction and hardware combinations.

Assessors may also take into account evidence from third party tests, e.g. tests sponsored by glass or hardware manufacturers, provided written permission is obtained from the test sponsor.

Most established metal fire door manufacturers have conducted tests over many years on a variety of doorset sizes, configurations, constructions and hardware combinations.

Characteristics of Fire Resisting Metal Doorsets

Appropriately designed and correctly installed metal doorsets can be capable of providing extended periods of fire resistance, however, the design and construction of metal fire resisting doorsets varies from manufacturer to manufacturer and performances when tested to BS 476: Part 22 may differ considerably.

Some designs may be prone to distortion and bowing leading to potential gaps occurring. Some designs, whilst more stable under test, may use core materials and adhesives that may release flammable gases. Either or these factors may lead to integrity failure under test.

Metal doorsets which do not satisfy the insulation criterion of BS 476: Part 22, conduct considerable levels of heat to the unexposed side of the assembly and even doors constructed with a degree of insulation are inclined to conduct high levels of heat at the perimeter of the door adjacent to the frame.

For this reason it should not be assumed that items such as hardware, glass and frame seals that have been tested with timber doors will perform satisfactorily with metal fire resisting doorsets unless supported by independent test evidence.

Evidence of Performance of Fire Resisting Metal Doorsets

Documented evidence of performance of the metal fire resisting doorset should be available from the door manufacturer, or their agent. The evidence of performance should be in the form of

• Product conformity certification

• Fire test reports or

• Assessment reports

The evidence should support the claimed performance for the complete fire doorset, as a combination of door, frame, glass, hardware and ancillary fittings.

The evidence of performance, which may be in one or several documents, should always state the maximum fire resistance performance for the complete doorset configurations.

Variations not included in the scope of evidence of performance may not have undergone an appropriate technical assessment and therefore they must be considered to be likely to affect the performance of the doorset.

Timber Fire Doors Installed In Metal Door Frames

It should not be assumed that timber fire doors installed in metal door frames will achieve the required performance unless the door product (facing, lipping, core and intumescent seals) has been satisfactorily tested in the proposed metal door frame assembly (hollow or back filled or with partition) and is covered by appropriate evidence of performance for sizes and door configuration. Such evidence should be available from the timber door manufacturer or his agent.

Hardware

Only hardware listed in the evidence of performance should be installed, unless alternative types are covered by CERTIFIRE, LPCB or other recognised approval schemes for installation with fire resisting metal doorsets, or approved evidence of performance is available from the hardware manufacturer, or his agent.

Metal doorset manufacturers may refuse to install specified hardware for which appropriate evidence of performance with metal doorsets is not available.

Locks and Latches

Where the scope of evidence of performance covers latched doorsets only, the doorsets must include locks incorporating a latch bolt, covered by evidence of performance as defined above.

Locking mechanisms that rely on manual operation only e.g. deadlocks, and bolts on the inactive leaf of pairs, should not be installed in fire resisting metal doorsets unless the scope of evidence of performance covers unlatched doors and the approval authority accepts their use.

Similarly the use of emergency exit (panic) hardware in which the components, essential in maintaining the door closed under fire conditions, are made with low melting temperature materials should not be installed in fire resisting metal doorsets unless the scope of evidence of performance covers unlatched doors.

Metal door manufacturers generally provide their own architectural quality steel hinges as part of the fire resisting metal doorset covered by the evidence of performance. Alternative hinges should not be installed unless covered by evidence of performance as defined.

Door Closing Devices, Surface Mounted, Single Action

Fire test evidence shows that surface mounted door closing devices fitted to the non-fire risk (unexposed) face of un-insulated fire resisting metal doorsets are susceptible to ignition of leaking fluid, causing integrity failure of the doorset.

Any surface mounted door-closing device may be fitted to the fire risk side of a latched metal doorset, provided the risk side can be positively identified. However, if the doorset is unlatched, or if both faces of the door are potentially at risk, whether latched or unlatched, only door closers covered by appropriate evidence of performance should be fitted.

Door Closing Devices, Concealed, Single Action

There are three categories of concealed single action door closer:

• Fitted in the head or transom of the frame

• Fitted within the top of the door leaf

• Edge mounted in the hinge side of the door leaf

These door-closing devices should only be installed in fire resisting metal doorsets when covered by appropriate evidence of performance.

Edge mounted door closing devices which do not incorporate a "snap action" facility to overcome latch bolt friction or to firmly hold unlatched doors in a closed position, are unsuitable for use with fire resisting doorsets.

Floor Spring Door Closers

With this type of closer the risk of integrity on the face of a door is minimal. However, as a metal door expands and bows stresses can build up at the floor pivot position that could lead to bursting of fluid seals and flaming at the bottom of the door. Evidence of performance that the floor spring has been tested with metal doors should be available.

Plastic Fittings

Signs, and other items of hardware made of, or containing plastic, should not be fitted to the non-fire risk (unexposed) side of metal fire doors or frames unless covered by appropriate evidence of performance.

Plastic signs may be suitably sited above or to the side of fire resisting metal doorsets. Metal signs may be fitted to the door leaf.
Electronic Door Control Key Pads

Electronic door control keypads are susceptible to flaming on the non-fire risk side of metal doors and frames and should not be in contact with either unless covered by evidence of performance.

Louvres, Letter plates And Door Viewers

Louvre’s, door viewers, letter plates and other items of hardware which require a significant penetration through a metal fire door should not be fitted unless covered by evidence of performance for the doorset assembly.

Installation

It is critical that correct methods of installation are adopted to ensure that the doorset, when fixed into the wall, will achieve the fire rating designated for the door opening.

It is strongly recommended that installation is carried out by the manufacturer or, alternatively, by installers trained in fixing metal fire doorsets to the manufacturers' fixing instructions. A recommendation of Approved Document B of the Building Regulations is that the installation of fire resisting products should be covered by product conformity certification e.g. LPCB or by independent registered installer schemes, e.g. FIRAS, where such schemes are available to cover metal doorsets.

Labelling

Every fire resisting metal doorset should bear the label of an accredited product conformity certification scheme, when the doorset is installed within the scope of that certification scheme. Otherwise it is recommended that the doorset should bear a label showing the manufacturers' name, the fire rating of the doorset and a traceable serial number.

Figure 1: Checking Doorsets

Evidence of Performance should include		Typical non-compliant deviations from the evidence of performance
Maximum door leaf size	For each door construction	Door widths or heights exceeding the maximum stipulated.
Door leaf construction	Door, face material, jointing, core material, internal framing or reinforcing, and door thickness	Changes to the internal framing or reinforcing, the core material, the door thickness, the door face or face material should not be made unless covered in the scope of the evidence of performance. In addition any perimeter forming for the purpose of maintaining integrity should not be altered.
Door configurations and action	Single leaf, double leaf, single swing, double swing, latched, unlatched	Any configuration or action excluded from the scope of the evidence of performance.
Vision Panels	Type of glass, glass size, shape, framing/beading, glazing material	Vision panel sizes exceeding the size tested or otherwise approved for the doorset. The performance characteristics of the different types of fire resisting glass installed in metal doors varies considerably and unauthorised substitution of the glass or the glazing system should not take place.
	Location of door closers adjacent to glazing	The glazed area of a vision panel should not extend beneath the position of an overhead door closer fitted to the non-fire risk side of a metal door unless the door closer is covered by appropriate evidence of performance for this type of location - refer to notes on door closing devices below.
Frames, profiles, fixings and wall construction	Identification of the frame type or profile and fixing requirements with types of wall covered - masonry, structural steelwork, stud partition etc.	Installation in supporting constructions not covered by the evidence of performance e.g. fire tests carried out in masonry walls only do not necessarily cover installation in stud partitions or vice-versa.
Over panels and side panels	Identification of arrangement details and maximum sizes	The size and construction of frames with over panels and side panels should not exceed or differ from that covered by the evidence of performance. The limitations governing substitution of fire resistant glass in over panels and side panels are as for vision panels.
Smoke seals	Type by brand name or performance specification	Frame seals can ignite and flame, causing integrity failure, when the frame and edge of a door reach critical temperatures. Only seals that are covered by the evidence of performance should be fitted. Incorrect seals can force open unlatched doors even when door closers are fitted.
Hardware	Model type and/or brand name of hinges, locks, door closers, and other items of hardware which may be fitted	Refer to notes below

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