IE20080919A1 - An improved fire door - Google Patents

Abstract

A fire door comprising at least two panels and an internal core interposed between the panels and at least onr peripheral edge extending around the top, bottom and sides of the door. Each panel is arranged relative to the internal core to form a U-shaped channel which extends around a perpipheral edge surface of the internal core, such that the peripheral edge surface of the internal core forms the base of the U-shaped channel. The U-shaped channel is adapted to recieve an internal supporting framework of fibreboard which, with the panels, surrounds and encloses the internal core, the internal supporting framework of fibreborad and the perpipheral edge of the panels being juxtaposed to form a planar edge surface extending around the top, bottom and sides of the door. A hardwood edging member surrounds the planar edge surface at the top, bottom and sides of the door. <Figure 1>

Description

AN IMPROVED FIRE DOOR The present invention relates to an improved fire door.

Other than for access, fire doors provide a vital function closing openings within a building to control spread of fires. In order to do this effectively each fire door must perform to a certain standard in the presence of a fire. A fire doors performance is certified if it achieves a predetermined performance level while being subjected to strictly controlled criteria under test. Various authorities carefully control and provide the basis for legislation for test criteria to determine the level of performance of a fire door. For example, in the United Kingdom, British Standard BS 8214:1990 which outlines the code of practice for fire door assemblies with non-metallic leaves is controlled by the Timber Standards Policy Committee. BS EN 1634-1:2000 is a new European Standard prepared by Technical Committee CEN/TC 127 ‘Fire Safety in Buildings’, the secretariat of which is held by British Standards Institute. BS EN 1634-1:2000 will supersede British standard BS 476 Pt 8 in due course.

It is known to make fire doors using door blanks wherein the door blank corresponds to a door panel. Typically a door blank is manufactured in large sheets of fire resistant material. The sheets are converted into the type and style of door by cutting the sheet to size and finishing it with lippings, adding door furniture including ironmongery and intumescent seals as required. Waste generated is dependant on the door configuration, naturally if the size of the blank supplied is close to the final door size smaller amounts of waste are generated. Generally the waste factor is at its highest when doors are of bespoke design which may incorporate doors of uncommon size or overpanels. It is not uncommon to discard 15% to 45% of the door blank material when making bespoke doors. Bespoke doors are required in most industrial and commercial offices and many municipal type buildings such as hospitals and colleges where doors with overpanels and off size standard leaves are present.

A known door blank comprises a solid timber laminate core between two facings. Typically the core comprises hardwood strips laminated together. The facings are commonly formed from plywood. This type of door leaf can only be manufactured using specialised plants and machinery. It is uneconomical to produce such a door leaf in small or medium quantities thus it can only be effectively manufactured in high volume.

Use of hardwood in the core of the door leads to further problems including telegraphing. Telegraphing is when core materials move independently of each other causing a pattern of irregularities to develop on the facings of the fire door. Each individual piece of timber in the hardwood core has its own individual stiffness and grain characteristic which accentuates movement hence irregularities. Furthermore, it is not uncommon for timber of the same density and species to have marked differing fire performance when tested. To ensure that a fire door with a hardwood core performs to the correct standard in the presence of a fire, it is essential that the door is conditioned properly, it is stored correctly and that the final environment is maintained in order to prevent telegraphing. If consistent performance is to be achieved between hardwood core fire doors tested and the subsequent doors manufactured there must be a high level of quality control employed. Regardless, performances of these types of doors are less predictable than when manufactured board is used in the core.

Use of manufactured board in the form of thick particleboard or chipboard has other problems associated with it. Particleboard or chipboard does not provide sufficient support for retaining screws which in turn causes problems when trying to fix door furniture such as locks and hinges in place. This type of door blank is also manufactured using specialised plant and machinery which causes it to be uneconomical to produce in small or medium quantities.

GB 2186015 discloses a fire door that includes an internal manufactured core with a surrounding framework of fibreboard. The framework surrounding the internal core comprises two vertical stiles and two horizontal rails of elongate members of fiberboard having cross sectional dimensions of 48mm x 50mm. The horizontal stiles at the top and bottom of the door in GB 2186015 are encapsulated by an internal 25mm hardwood rail. This is a complicated structure which is time consuming and expensive to manufacture. This structure is also susceptible to considerable telegraphing if not stored correctly When a material is exposed to flames the outside edges are affected most vigorously and erosion at a radius corner on the outermost edges develops, this is known as the burn curve. When this radius meets the radius at the opposing corner erosion of the thickness of the material becomes much more rapid. This effect occurs most prominently on the corners at the head or top and bottom of a door. At the top and bottom of the door of GB 2186015 panels cover the hardwood thus the panels are exposed to »989919 more vigorous burning in the presence of a fire. When this occurs the panels tend to curl and peel away from the hardwood and internal frame, which would ultimately lead to exposure of the internal core. Once the frame and core are exposed on more than one face the door begins to breakdown more rapidly. A significant problem with current fire doors is that it is not possible to use fire doors of the type disclosed in GB 2186015 with steel door frames due to the effect of the burn curve. The intensity of the heat from the metal frame causes the door to burn more vigorously thus accelerating breakdown of the door.

An object of the present invention is to overcome the problems associated with known fire doors and their construction.

The present invention provides a fire door in the form of a rectangular parallelepiped having a top, a bottom and two sides, The fire door comprising at least two panels and an internal core interposed between the panels, in a plane transverse to the top, bottom and two sides of the door, each panel comprising an inner and outer planar surface and at least one peripheral edge extending around the top, bottom and two sides of the door, the internal core comprising at least two planar surfaces and at least one peripheral edge surface intermediate the planar surfaces, the inner planar surface of each panel being arranged relative to the internal core to form a U-shaped channel comprising two parallel elements and a connecting element, which extends around the peripheral edge surface of the internal core, such that the peripheral edge surface of the internal core forms the connecting element of the U-shaped channel, the U-shaped channel is adapted to receive an internal supporting framework comprising two parallel vertical stiles and two parallel horizontal rails of fibreboard arranged to surround the internal core such that the internal supporting framework together with the panels surrounds and encloses the internal core at the top, bottom and two sides, the internal supporting framework of fibreboard and the peripheral edge of the panels being juxtaposed to form a planar edge surface extending around the top, bottom and sides of the door and a hardwood edging member surrounding the planar edge surfaces at the top, bottom and sides of the door.

Advantageously the hardwood edging member covers the internal supporting framework and protects the edges of the panels at each of the corners. This significantly improves the capacity of the fire door of the invention to resist erosion at the radius corners thus reducing the effect of the burn curve on the corners at the head or top and bottom of a door. This also removes the need for the hardwood rail as disclosed in GB 2186015 which in turn has both cost and production advantages over the previous design.

Ideally when forming the internal supporting framework the at least two vertical stiles and at least two horizontal rails of fibreboard are spaced apart from each other to form opposing sides of a rectangular parrallelpiped. Thus when surrounding the internal core in the door, the internal supporting framework comprises a single vertical stile at each side of the fire door and a single horizontal rail at the top and bottom of the fire door respectively. Advantageously reducing the size of the internal supporting framework reduces the effect of telegraphing. This advantage maintains the integrity of the fire door of the invention even if the fire door is stored or used in less suitable environmental conditions.

Advantageously the fire door of the present invention is designed and constructed to meet current safety standards as set out in Standard BS 476 Pt 8 and Standard BS EN 1634-1:2000. Both of these standards involve exposure to a controlled fire within laboratory conditions where the door sample is tested to destruction. Advantageously the fire door of the present invention has FD3O and FD6O performance, wherein the fire door maintains its integrity when exposed to a fire under standard testing conditions for 30 minutes and 60 minutes respectively. Furthermore the unique construction of the fire door of the present invention ensures that this fire door is suitable for use in a metal door frame and meets the current safety standards as set out above when used is such a door frame.

A further significant advantage of the invention is that the fire door can be manufactured using simple construction processes. It does not require extensive setting up times and is suitable for all size production runs. When the door size and design is known the internal supporting framework is cut to size and filled with internal core material of the appropriate type. Accordingly there are significant production savings when manufacturing this fire door over the fire door which is disclosed in GB 2186015.

The present invention further provides a method for making a fire door in the form of a rectangular parallelepiped having a top, a bottom and two sides comprising the steps of: (a) sizing an internal core; (b) surrounding the internal core with at least two vertical stiles and at least two horizontal rails of fibreboard to form an internal supporting framework of fibreboard, the internal supporting framework having a peripheral edge member remote from the internal core; (c) interposing the internal core and internal supporting framework between two panels in a plane transverse to the top, bottom and sides of the door, wherein, each of the panels comprises an inner and outer planar surface and at least one peripheral edge extending around the top, bottom and sides of the door, and wherein the inner planar surface of each panel is arranged relative to the internal core and the internal supporting framework of fibreboard such that the peripheral edge of the panels are juxtaposed to the peripheral edge of the internal supporting framework to form a planar edge surface extending around the top, bottom and sides of the door; and (d) surrounding the planar edge surfaces at the top, bottom and sides of the door with a hardwood edging member.

In the preferred embodiment of the invention the panels and internal supporting framework form the door shape and size. This is in the form of a rectangular parallelepiped wherein the panels are substantially the size of the opening to be closed and the internal supporting framework is substantially the depth of the opening to be closed. Conveniently the panels support the entire door construction. Ideally the fire door is supported in the opening to be closed by a doorway frame.

In the preferred embodiment of the invention the stiles and rails of the internal supporting framework comprise an elongate fibreboard element. Conveniently the fibreboard comprises medium density fibreboard (MDF) or plywood. Ideally in the preferred embodiment the stiles and rails comprise MDF which is approximately 25 mm wide and which is then cut to the appropriate length. Reducing the size of the internal supporting framework reduces the effect of telegraphing even if the fire door is stored or used in less suitable environmental conditions.

Ideally in the preferred embodiment the hardwood edging member comprises at least two vertical stiles and at least two horizontal rails of elongate members. Advantageously in the preferred embodiment the hardwood edging member completely surrounds the planar edge surfaces at the top, bottom and sides of the door. Optionally the hardwood edging member is a 10mm strip cut to the appropriate length. Ideally the density of the hardwood used to form the edging member is in the range 350kgm'3 to 700kgnV3. More preferably the density of the hardwood used to form the hardwood edging member is in the region of approximately 520kgm’3 Ideally the panels are chosen to prevent erosion of the door which can be a weakness of many door designs when subjected to fire testing. Conveniently the panels also support the door construction, as in the event of a fire the facing on the unexposed side remains functional and provides necessary support for the door. Optionally the panels can be further faced with either decorative veneer, laminates or prepared for painting as required by the user.

Preferably the internal core is composed of fire resistant material, for example, flaxboard, particleboard, chipboard or laminated chipboard. It is of course understood that any suitable fire resistant material known to the person skilled in the art may also be used. Preferably in one embodiment the internal core comprises two sheets of fire resistant material, each of which is 18mm in thickness. Advantageously this embodiment of the fire door has FD3O performance characteristics. In a further embodiment of the fire door the internal core comprises three sheets of fire resistant material, which are 18mm, 12mm and 18mm in thickness respectively. Advantageously this embodiment of the door has FD6O performance characteristics. Conveniently this results in a door thickness of approximately 44mm and 56mm respectfully, which coincides with the standard thickness of doors of each performance characteristic.

A further advantage of this invention is that the internal core is composed of manufactured material. This removes the effects of fire performance on the variable characteristics of natural wood materials. It is not uncommon for timber of the same density and species to have marked differing fire tested performances. The fire door of the present invention achieves consistent performance when tested.

Conveniently the panels and internal supporting framework may also be used to frame openings in doors such as vision panels and facilitate formation of ancillary openings for vision panels and the like within the door or over-sized doors. It is of course understood by the person skilled in the art that the number and size of openings and/or view panels within a door is not limited.

The door is constructed using panels to conceal the core. Optionally the core can be formed using several core pieces rather than one full size piece. Advantageously this further facilitates the inclusion of vision panels and formation of ancillary or over-sized doors.

Failure of door designs when fire tested is often attributable to door deflection or warping while under test. Forming the core using several parts can benefit fire performance. In the presence of a fire each piece of core deflects independently, thereby ensuring that the door, although deflecting, does so in a series of small movements rather than in one continuous curve and therefore is more likely to remain within the door frame increasing the door's performance.

A further advantage of this invention is that the internal supporting framework together with the hardwood edging member provide sufficient support for the retention of screws used for fixing hinges and locks. In the preferred embodiment the internal frame is a 25mm strip and the hardwood edging member is a 10mm strip, together providing a depth of 35mm. Conveniently if a 30mm screw fixing is used, it remains completely within the internal supporting framework of the door thereby ensuring quality screw retention. Advantageously 30mm is the most commonly used size screw for the purpose.

Responsibility for fire performance certification lies with the door manufacturer or the company whom convert door blanks to a fire door. This can lead to difficulties and improper product being incorporated within the marketplace. A further advantage of the invention is that it provides the option to extend the range of sizes available for the fire door whilst retaining the certification of fire performance through testing. This is not possible with fire doors constructed from door blanks.

Advantageously the manufacturer of the fire door of the invention is identifiable by the mere fact that the entire door is constructed at one location. For example in common «080919 practice when currently constructing fire doors at multiple locations, ambiguity can arise when it comes to certification as to which company is actually responsible for the manufacture of the door. Furthermore control over the product as tested can be misrepresented or misinterpreted, thus it is not an uncommon experience to find construction details being transferred with less than correct detail, rendering the door ineffective as a fire door. With this in mind it can be understood that a single source with responsibility for the fire doors performance is preferable to conversion of door blanks which is current practice with prior art fire doors.

Optionally one or more strips of intumescent material are disposed in the hardwood edging member and/or the doorway frame supporting the door. In the presence of a heat the intumescent strip expands thereby sealing the opening between the door and the doorway frame. This is the widely employed method of preventing the fire passing through the clearance gaps between door and frame, which are required to allow door and frame to function. Advantageously the fire door of the invention requires less intumescent material than the fire door known in the prior art.

Advantageously the fire door of the present invention is cheaper and easier to manufacture than those currently on the market whilst improving performance and product quality.

The invention will hereinafter be more particularly described with reference to the accompanying drawings which illustrate by way of example only, an embodiment of the invention.

In the drawings; Figure 1 is a sectional top view of a portion of a fire door of the invention; Figure 2 is a sectional view of the fire door of the invention; Figure 3 is a enlarged sectional view I of a portion of the fire door of Figure 2; and Figure 4 is a cut away perspective view of a comer of the fire door of Figure 1; *089919 Figure 5 is a side view of Doorsets 1A and 1B showing the measuring points for Doorset Clearance Gaps in the Fire Resistance Performance Tests.

Figure 6 is a graph showing mean furnace temperature, together with the temperature/time relationship specified in the Standard BS EN 1634-1:2000; Figure 7 is a graph showing mean temperatures recorded on the unexposed surface of Doorset 1A; and Figure 8 is a graph showing mean temperatures recorded on the unexposed surface of Doorset 1B.

Referring to the drawings and initially to Figure 1 there is shown a sectional top view of a portion of fire door 1. Fire door 1 comprises panels 3a and 3b and internal core member 2 interposed between the panels 3a and 3b. The internal core is surrounded by an internal supporting frame member 4. The internal supporting framework member and the panels are juxtaposed to form a planar edge surface, fire door 1 further comprising a hardwood edging member 5, which extends around the planar edge surface surrounding and enclosing the planar edge surface.

The door is mounted by means of hinges 9 to a timber or metal doorframe 7. Door stop 8 forms part of the doorframe 7. The hinges 9 are secured to both the doorframe 7 and the fire door 1 by means of screws 10. The screw penetrates the hardwood edging member 5 and internal supporting framework member 4 thereby ensuring quality screw retention.

In Figure 2, there is shown a sectional view of fire door 1. Figure 3 is an enlarged section view of portion I of fire door 1 showing the arrangement of the internal supporting framework 4 and hardwood edging member 5 around internal core 2.

Fire door 1 comprises internal core 2 which is divided into a number of individual pieces which are then fixed together by appropriate means such as gluing. This facilitates the insertion of a viewing panel 11. The viewing panel 11 is composed of any suitable transparent material for example glass or Perspex (RTM) and so forth. The viewing panel 11 is further supported by framing strips of fibreboard 6a to 6d respectively. The strips of fibreboard typically comprise two 25mm horizontal rails 6a and 6d, and two 25mm vertical «080919 stiles 6b and 6c of MDF. The framing strips 6a to 6d provide further protection in the event of a fire for the internal core 2 due to their fire retardant properties.

The internal core 2 is surrounded by the internal supporting framework 4, which comprises two 25mm vertical stiles 4a and 4c and two 25mm horizontal rails 4b and 4d. The panels 3a and 3b (not shown) cover in effect the front and back panels of fire door 1 such that the internal supporting framework 4 and the peripheral edge of the panels 3a and 3b form a planar edge surface. The planar edge surface is completely surrounded and enclosed by the hardwood edging member 5. Hardwood edging member 5 comprises two 10mm vertical stiles 5a and 5c and two 10mm horizontal rails 5b and 5d. The hardwood edging member protects the peripheral edge surfaces of the panels 3a and 3b from immediate exposure to flames in the event of a fire. This slows down the burn curve at the corners of fire door 1 and thereby improves the performance characteristics of fire door 1 even though there is reduced volume of fire retardant material in the internal supporting framework 4.

Figure 4 shows a cut-away perspective view of a corner of fire door 1. Figure 4 shows a vertical stile 5a and horizontal rail 5b of hardwood engaging member 5 surrounding the planar edge surface thus surrounding and enclosing the internal supporting framework 4 and the edges of the panels 3a and 3b (3b not seen). This protects the edges of the panels 3a and 3b from succumbing as quickly to the effects of the fire.

Referring now specifically to Figures 5 to 7. Fire Door 1 was subjected to a fire resistance performance test in accordance with European Standard BS EN 1634-1:2000. For the purpose of the test two samples of fire door 1, samples 1A and 1B respectively, were hung within mild steel frames using four stainless steel hinges and were mounted within a low density rigid supporting construction. It is understood by the person skilled in the art that hanging the fire door for testing within a mild steel frame provides a more onerous test scenario than if a timber frame is used. The overall dimensions of each doorset, comprising fire door samples 1A and 1B and the frames were 2443 mm x 1016 mm x 45 mm whilst the overall dimensions of each fire door sample 1A and 1B were 2400 mm x 930 mm x 45 mm. Fire door samples 1A and 1B comprised Medium density fibreboard stiles and rails, a chipboard core, Medium density fibreboard inner facings with a decorative laminate outer facing and hardwood lippings on the vertical edges.

Doorset 1A was fitted with a surface mounted overhead door closer, this was mounted on the exposed face in projecting arm configuration. Doorset 1B was fitted with a surface mounted overhead door closer mounted on the unexposed face in projecting arm configuration. Doorset 1A was also fitted with a glazed aperture comprising of Medium density fibreboard framing, ‘Pilkington Pyroshield (RTM) Polished Wired Glass’ and hardwood beading. Doorset 1A was mounted such that it opened towards the heating conditions of the test and Doorset 1B was mounted such that it opened away from the heating conditions of the test, both doorset were unlatched for the duration of the test.

Schedule of Components for Fire Resistance Performance Test Item 1. Door Frame Material Thickness Overall section size Jambs to head jointing method Fixings to masonry i. method ii. fixing size iii. reinforcing plates iv. frequency 2. Door Leaf Stiles and Rails Material Description Mild steel, painted finish. 1.5 mm. 125 mm x 60 mm.

Butt joined and fixed together with 2 no. 8 mm diameter bolts.

Countersunk steel screws into plastic plugs fixed through a mild steel reinforcing plate welded to the back of the frame. Intumescent mastic was applied around the edges of the frame to the masonry wall. mm diameter x 75 mm long. mm deep x 3 mm thick plates.

No. fixings to jambs, positioned 100 mm up from the bottom edge then 740 mm centres.

Medium density fibreboard (MDF) DEO 8 Ο 9 1 β Density Overall section size Jointing method Adhesive 3. Door Leaf Core Material Density Thickness Fixing method Adhesive 4. Door Leaf Inner Facings Material Thickness Fixing method Adhesive . Door Leaf Outer Facings Material Thickness Fixing method Adhesive 6. Aperture Framing to Door A Material Density Overall section size Jointing method 720 kg/m3. mm x 36 mm.

Stiles and rails butt joined and fixed with steel staples, 15 mm x 25 mm x 1 mm. Urea formaldehyde.

Chipboards. 550 to 600 kg/m3. layers each being 18 mm thick.

The core to door leaf B was butt joined horizontally and the joints were coincident. The chipboards layers were glue fixed Together.

Urea formaldehyde.

Medium density fibreboard (MDF). 3.6 mm.

Glue fixed.

Polyvinyl acetate (PVA).

Decorative laminate. 0.6 mm.

Glue fixed.

Polyvinyl acetate (PVA).

Medium density fibreboard (MDF). 720 kg/m3 25 mm x 36 mm.

Butt joined and fixed with steel staples, mm x 25 mm x 1 mm. 7. Lippings Material Sapele hardwood. Density 550 to 650 kg/m3 Thickness 16 mm. Size 45 mm wide. 8. Door Leaf Intumescent Seal Manufacturer Mann McGowan. Reference 100P. Material Palusol (RTM). Overall section size 20 mm x 4 mm. Fixing method Self adhesive to perimeter edge of door leaf. 9. Glass Manufacturer Pilkington. Reference Pyroshield (RTM) Polished Wired Glass. Thickness 6.4 mm. Glass sight size 200 mm wide x 400 mm high. Nominal edge clearances 5 mm. 10. Glazing Beads Material Sapele hardwood. Density 550 to 650 kg/m3 Size Fixings 29 mm by 23 mm with 5 mm bolection return. i. type Steel nail pins. ii. size 1 mm diameter by 50 mm. iii. skew angle approximately 30 degrees. iv. frequency 3 No. to horizontal edges at 75 mm centres.

No. to vertical edges at 65 mm centres. 11. Glass Edge Seal Manufacturer and reference Material Not stated. Intumescent mastic. 12. Hinges Manufacturer Not stated. Reference CE Mark BS EN 1935 Grade E13. Primary material Overall size Stainless steel. i. knuckle 14 mm diameter x 110 mm. ii. blades 30 mm x 100 mm x 2.5 mm thick. Details of fixings to frame i. type Steel alien head screws into a steel reinforcing plate welded to the frame. ii. material Steel. iii. size 6 mm diameter x 32 mm long. iv. quantity per blade Details of fixings to leaf i. type ii. material 4. Countersunk steel screws. Steel. iii. size 6 mm diameter x 70 mm. iv. quantity per blade Bedding material 4. None. 13. Lock and Handleset Lock reference CFC1121. Primary material Polished mild steel lock and plates with stainless steel throw. Overall sizes i. forend 24 mm wide x 35 mm deep. ii. strike plate 24 mm wide x 235 mm deep with a 28 mm deep box for the lock. iii. casing iv. latch bolt throw 88 mm wide x 165 mm deep. 10 mm. Barrel manufacturer ISEO (Italy). Barrel type Door A fitted with knob on unexposed face and key slot to exposed face. Door B fitted with turn knob on exposed face «08Η1Ι Barrel material Lever handle and escutcheon material Lever handle size Operation of latch Bedding material 14. Overhead Door Closer Reference Material Location Body size Maximum opening moments i. Doorset ΊΑ' ii. Doorset ΊΒ’ Maximum closing moments i. Doorset11 A’ ii. Doorset ΊΒ’ and key slot to unexposed face.

Stainless steel.

Stainless steel with mild steel backing plate to Escutcheon. mm diameter x 135 mm long with 52 mm diameter escutcheon.

Disengaged.

None.

FRD Closer, F6424BC, size ADJ EN2-4. Aluminium body with steel arms.

Exposed face of door leaf 1 A.

Unexposed face of door leaf 1B. 208 mm x 60 mm x 40 mm deep.

Newton metres (Nm).

Nm.

Nm.

Nm.

Storage of fire door 1A and 1B, construction of fire doorset 1A and 1B and test preparation took place in the test laboratory over a total, combined time of 6 days. Throughout this period of time both the temperature and the humidity of the laboratory were measured and recorded as being within a range of from 12°C to 22°C and 34% to 64% respectively.

Doorset clearance gaps Door Ref Gap Dimension in mm at Positions A 1 2 3 4 5 6 7 8* 9* 10* 11 12 13 14 1.9 1.4 1.2 3.1 2.5 3.0 2.4 5.9 6.0 5.8 2.2 2.3 2.6 2.5 B 15 16 17 18 19 20 21 22* 23* 24* 25 26 27 28 1.5 2.0 1.7 2.7 3.2 3.1 2.4 5.1 5.2 5.0 3.0 2.8 2.5 2.1 A Mean 2.2 Maximum 3.1 M inimum 1.2 B Mean 2.4 Maximum 3.0 Minimum 1.5 Door Ref Gap Between Face of Leaf and Doorstop in mm at Position A 1 2 3 4 5 6 7 8# 9# 10# 11 12 13 14 3.9 3.1 2.7 0.6 0.5 0.8 0.9 2.4 3.8 4.5 4.9 B 15 16 17 18 19 20 21 22# 23# 24# 25 26 27 28 1.2 1.8 2.1 1.2 1.4 1.8 1.9 3.8 4.2 4.7 3.4 *Dimension not included in calculations # Gap not measured Instrumentation General The instrumentation was provided in accordance with the requirements of the Standard.

Furnace The furnace was controlled so that its mean temperature complied with the requirements of the testing standard using six plate thermometers, distributed over a plane 100 mm from the surface of the test construction.

General Thermocouples were provided to monitor the unexposed surface of the specimen and the output of all instrumentation was recorded at no less than one minute intervals.

The locations and reference numbers of the various unexposed surface thermocouples are shown in Figure 1.

Roving Thermocouple A roving thermocouple was available to measure temperatures on 25 the unexposed surface of the specimen at any position, which might appear to be hotter than the temperatures indicated by the fixed thermocouples.

Integrity Criteria Radiation Cotton pads and gap gauges were available to evaluate the integrity of the specimen.

A water-cooled foil heat-flux meter was used to record the heat radiation from Doorset A. The heat flux meter was positioned at a distance of 1 metre from the unexposed surface of the Doorset A.

Furnace Pressure The furnace atmospheric pressure was controlled so that it complied with the requirements of the testing standard. Clause 5.2. The calculated pressure differential relative to the laboratory atmosphere at the top of the specimens was 16.5 (±3) Pa.

Test Observations Time All observations are from the unexposed face unless noted otherwise.

The ambient air temperature in the vicinity at the test construction was 14°C at the start of the test with no variation during the test. mins secs 00 00 The test commences. 00 38 The glass pane starts to crack on Doorset 1A. 00 58 Smoke release starts at the head of both doorsets. 01 40 The exposed faces of both doorsets have ignited; the laminate face on both doorsets is starting to come away. 03 38 Smoke release increases form the top two hinge positions on Doorset 1B. Smoke release also starts to increase from the two top corners of Doorset 1A. 05 00 Smoke release starts around the latch positions on both doorsets. 06 20 Viewed from the exposed side remnants of the laminated face are still attached to both doorsets, the exposed faces 56 56 00 00 00 00 00 00 00 00 00 00 50 00 00 appear blackened.

Black residue runs down the trailing edge of Doorset 1B from the second to top hinge position downwards.

Smoke release is visible and a dark patch of discolouration forming on the trailing edge of Doorset 1A. Just above % height.

Thermocouple 27 on the left hand vertical edge of the frame on Doorset 1B, exceeds a 360°C rise. Insulation failure is deemed to have occurred.

A dark brown residue is running down the leading edge of the Doorset 1B from the head down to just below mid-height. A dark brown residue can be seen running on the leading edge of Doorset 1A, from the top of the door and from around mid-height.

Discolouration increase at the top of the trailing edge of Doorset 1 A, roughly equivalent to the hinge positions.

The laminate has now totally fallen away from the exposed faces of both doorsets.

The frame of Doorset 1B has discoloured black on both its vertical faces.

A black residue can be seen bubbling out at a couple of locations on the trailing edge of Doorset 1A.

Overall there has been very little deflection of both doorsets. Doorset 1B is proud of the frame by a couple of mm along its leading edge.

The lipping at the bottom of Doorset 1B starts to deteriorate around mid-span.

Only the arm of the exposed closer remains on Doorset 1 A. Discolouration starts to increase at the head of Doorset 1 A. A cotton wool pad is tested in the top trailing edge corner of Doorset 1 A, around an area of dark discolouration, the cotton fails to ignite.

Doorset 1A continues to satisfy the test criteria, Doorset 1B continues to satisfy the integrity criteria of the test.

The lipping falls way at the bottom of Doorset 1 A, at its leading edge corner. 31 30 Intermittent flaming seen in the top leading edge corner of Doorset 1A. 32 00 Sustained flaming seen in the trailing edge corner of Doorset 1A. Sustained flaming failure deemed to have occurred. 33 00 Smoke starts to issue from the closer on Doorset 1B. 33 40 Intermittent flaming seen along the threshold of Doorset 1B 35 00 Glowing can now be seen around the frame at mid-height of the trailing edge on Doorset 1B. 36 00 Sustained flaming seen along the leading edge of Doorset 1B starting at the bottom. Sustained flaming failure is deemed to have occurred. 37 00 The test is discontinued at the sponsor’s request.

Performance Criteria and Test Results Integrity It is required that the specimen retains its separating function, without either causing ignition of a cotton pad when applied, or permitting the penetration of a gap gauge as specified in testing standard or resulting in sustained flaming on the unexposed surface. These requirements were satisfied for the periods shown below: Doorset 1A Doorset 1B Sustained flaming 32 minutes 36 minutes Gap gauge 37 minutes* 37 minutes* Cotton pad 32 minutes 36 minutes Insulation The mean temperature rise of the unexposed surface shall not be greater than 140°C and that the maximum temperature rise shall not be greater than 180°C (except on the doorframe, where the maximum temperature rise shall not exceed 360°C). Insulation failure also occurs simultaneously with integrity failure as specified in testing standard These requirements were satisfied for the periods shown below: Doorset A Doorset B Insulation 33 minutes 11 minutes The test duration. The test was discontinued after a period of 37 minutes.

It will of course be understood that the invention is not limited to the specific details described herein, which are given by way of example only, and that various modifications and alterations are possible within the scope of the invention as defined in the appended claims.

Claims (19)

CLAIMS:

1. A fire door in the form of a rectangular parallelepiped having a top, a bottom and two sides, the fire door comprising at least two panels and an internal core interposed between the panels, in a plane transverse to the top, bottom and two sides of the door, each panel comprising an inner and outer planar surface and at least one peripheral edge extending around the top, bottom and two sides of the door, the internal core comprising at least two planar surfaces and at least one peripheral edge surface intermediate the planar surfaces, the inner planar surface of each panel being arranged relative to the internal core to form a U-shaped channel comprising two parallel elements and a connecting element, which extends around the peripheral edge surface of the internal core, such that the peripheral edge surface of the internal core forms the connecting element of the U-shaped channel, the U-shaped channel is adapted to receive an internal supporting framework comprising two parallel vertical stiles and two parallel horizontal rails of fibreboard arranged to surround the internal core such that the internal supporting framework together with the panels surrounds and encloses the internal core at the top, bottom and two sides, the internal supporting framework of fibreboard and the peripheral edge of the panels being juxtaposed to form a planar edge surface extending around the top, bottom and sides of the door and a hardwood edging member surrounding the planar edge surfaces at the top, bottom and sides of the door.

2. A fire door as claimed in Claim 1, wherein the at least two vertical stiles and at least two horizontal rails of the internal supporting framework comprises medium density fibreboard (MDF).

3. A fire door as claimed in Claim 1, wherein the at least two vertical stiles and at least two horizontal rails of the internal supporting framework comprises plywood.

4. A fire door as claimed in any one of the previous claims, wherein the hardwood edging member comprises at least two vertical stiles and at least two horizontal rails.

5. A fire door as claimed in any one of the previous claims, wherein the density of the hardwood edging member is in the range 350kgm' 3 to 700kgm' 3 ,

6. A fire door as claimed in Claim 5, wherein the density of the hardwood edging member is approximately 520kgm' 3 .

7. A fire door as claimed in any one of the previous claims, wherein the internal core is composed of fire resistant material.

8. A fire door as claimed in Claim 6, wherein fire resistant material is selected from one or more groups comprising flaxboard, particleboard, chipboard or laminated chipboard.

9. A fire door as claimed in any one of the previous claims, wherein the internal core comprises two sheets of fire resistant material.

10. A fire door as claimed in claim 9, wherein the sheets of fire resistant material have a depth of 18mm.

11. A fire door as claimed in any one of Claims 1 to 8, wherein the internal core comprises three sheets of fire resistant material.

12. A fire door as claimed in claim 11, wherein two sheets of the fire resistant material have a depth of approximately 18mm and one of the sheets has a depth of approximately 12mm.

13. A fire door as claimed in any one of the previous claims, wherein the depth of the fire door is approximately 44mm or 56mm.

14. A fire door as claimed in any one of the previous claims, wherein the panels and internal supporting frame work frame openings in the fire door thereby facilitating formation of ancillary openings for vision panels and the like within the door or over-sized doors. »080 9 1 $

15. A fire door as claimed in any one of the previous claims, wherein the core is formed using several core pieces rather than one full size piece

16. A fire door as claimed in any one of the previous claims, wherein one or more strips of intumescent material are disposed in the hardwood edging member and/or the doorway frame supporting the door.

17. A method for making a fire door in the form of a rectangular parallelepiped having a top, a bottom and two sides comprising the steps of: (a) sizing an internal core; (b) surrounding the internal core with at least two vertical stiles and at least two horizontal rails of fibreboard to form an internal supporting framework of fibreboard, the internal supporting framework having a peripheral edge member remote from the internal core; (c) interposing the internal core and internal supporting framework between two panels in a plane transverse to the top, bottom and sides of the door, wherein, each of the panels comprises an inner and outer planar surface and at least one peripheral edge extending around the top, bottom and sides of the door, and wherein the inner planar surface of each panel is arranged relative to the internal core and the internal supporting framework of fibreboard such that the peripheral edge of the panels are juxtaposed to the peripheral edge of the internal supporting framework to form a planar edge surface extending around the top, bottom and sides of the door; and (d) surrounding the planar edge surfaces at the top, bottom and sides of the door with a hardwood edging member.

18. A fire door substantially as herein described with reference to and as shown in the accompanying drawings.

19. A method for making a fire door substantially as herein described with reference to and as shown in the accompanying drawings.