GB2584872A

GB2584872A - Glazing bar

Info

Publication number: GB2584872A
Application number: GB1908737.8A
Authority: GB
Inventors: Jarvis Will; Blackaller Neil
Original assignee: METFLAM Ltd
Current assignee: METFLAM Ltd
Priority date: 2019-06-18
Filing date: 2019-06-18
Publication date: 2020-12-23
Also published as: GB201908737D0

Abstract

A glazing bar (1, fig 1) for a fire-retardant glass door having a bridging portion 10 between two panes of glass 70, 75, two upstanding portions 20, 22 set in from each end of the bridging portion for receiving a sealant 60, 65 to fix the bar to the panes. The upstanding portions form a reservoir 30, 35 for an intumescent material. There may be a third upstanding portion 24 to form two reservoirs and the portions may partially enclose the reservoirs to retain the material at an optimum temperature. The third member may support a draught seal (50, fig 3) and the bar may be included in an assembled fire-proof door. Also provided is a fire-retardant glass door comprising a glazing bar and a glazing bar with the first and second upstanding portions not set in from the ends of the bridging portion.

Description

Glazing bar

Field of the invention

The present disclosure relates to a glazing bar for a glass door, and in particular a 5 glazing bar for a fire retardant glass door.

Background

The walls and inner fire-zone partitions of modern buildings are generally fabricated using materials that are known to impede the spread of fire. However, weak points in the resistance to fire may occur at the locations of apertures in the walls or partitions. For example, fire may take less time to traverse a closed window or door than it would to traverse a solid wall. Accordingly, many jurisdictions have buildings regulations that set out fire performance requirements for newly installed windows, doors, and partitions. In the United Kingdom, doors and windows that are installed in regulated building zones must comply with a given fire resistance as determined in accordance with British Standard 476: part 22: 1987 "Methods for determination of the fire resistance of non-load bearing elements of construction" and/or BS EN 1364-1:2015 "Fire resistance tests for non-loadbearing elements", the whole contents of both of which are hereby incorporated by reference.

British Standard 476 sets out methods for assessing both the integrity and the insulating properties of doors and windows when subjected to fire. Window and door integrity during a fire is important for preventing the direct spread of fire, and the insulating properties of a window or door are important during a fire both for preventing any materials that are adjacent to the door or window from reaching their ignition point, and for sheltering any people that may be behind the door or window. Integrity and insulating performance for a given door or window may be given in terms of a time value, for example, under test conditions a specific door may have met the required integrity criteria for 30 minutes but have only met the required insulating criteria for 20 minutes.

For apertures that are specified to have a translucent or transparent filling, such as windows or glass doors, special glazed materials that have fire retardant properties generally need to be used in order for the door or window to comply with buildings -2 -regulations. Example glasses that may be suitable are: Promat® SYSTEMGLASO glass, POLFLAM® glass and VETROTECH SAINT-GOBAINO CONTRAFLAM® glass.

From a fire resistance perspective, the interface between a fire retardant glazed pane and its surround is a potential a point of weakness and may cause reduced performance with respect to the pane and/or aperture surround or may necessitate bulky additional door or window furniture to avoid reduced performance. For example, the stiles of glazed fire retardant doors are typically 70 to 90 mm wide which can limit the glazed surface area that is available for the passage of light and may also be unaesthetic.

Summary of the invention

Aspects of the invention are as set out in the independent claims and optional features are set out in the dependent claims. Aspects of the invention may be provided in conjunction with each other and features of one aspect may be applied to other aspects.

According to a first aspect there is provided a glazing bar for a fire-retardant glass door. The glazing bar comprises a bridging portion configured to bridge between two panes of glass of the fire-retardant glass door, and a first upstanding portion and a second upstanding portion extending from the bridging portion. The first and second upstanding portions are set in from each end of the bridging portion for receiving a sealant to secure the glazing bar to the respective panes of glass. The first and second upstanding portions are arranged to form a reservoir therebetween for holding an intumescent material.

It will be understood that the glazing bar bridges between the two panes of glass of the fire-retardant glass door in a direction perpendicular or orthogonal to the planes of each pane of glass, but that the glazing bar may extend along an edge of the fire-retardant glass door along a longitudinal axis in a direction parallel to the planes of the panes of glass of the fire-retardant glass door. As such, the glazing bar is elongate along the longitudinal axis. When reference to each end of the bridging portion is made in this description, this is taken to mean each end of the bridging portion as taken in the direction orthogonal to the planes of each pane of glass, rather than in a direction along the longitudinal axis of the glazing bar. -3 -

The glazing bar seals to a glass door separately on either side of the glazing bar using a sealant such as silicone between the glass and the upstanding portions (that are set in from each end of the bridging portion) such that the panes of glass are independently 5 sealed to respective sides of the glazing bar at each end of the bridging portion. The reservoir between the upstanding portions, that comprises the intumescent material, may produce a seal between the door and a doorframe of the door in the event of a fire. Providing a seal beneficially prevents smoke and gas from escaping through the door and also helps to protect the panes of glass that are not under attack from flames of the 10 fire.

The upstanding portions may extend from the same side of the bridging portion. The upstanding portions may extend in direction to parallel to one another. The upstanding portions may also be configured to extend in a direction parallel to the panes of glass, for example parallel to but spaced away from the panes of glass. The upstanding portions may therefore extend in a direction perpendicular to the bridging portion, however it will be understood that in other examples the upstanding portions may extend in a direction transverse to the bridging portion, for example at an angle (for example, at an angle other than perpendicular, for example less than 80 degrees) relative to the bridging portion and optionally at an angle relative to each of the panes of glass which may be configured to be held perpendicularly to the bridging portion. In such examples the first and second upstanding portions may each extend at the same angle relative to the bridging portion. The first and second upstanding portions may be the same length.

The glazing bar may comprise respective receiving portions configured to receive a sealant to secure the glazing bar to the respective panes of glass. The respective receiving portions may be defined by the respective first and second upstanding portions, the respective glass panes and respective inset portions of the bridging portion (wherein the inset portions of the bridging portion are the portions at each end of the bridging portion by which the upstanding portions are set in from each of the ends of the bridging portion). The respective inset portions may therefore comprise the respective portions of the bridging portion remaining between the respective first and second upstanding portions and each end of the bridging portion. -4 -

Optionally, the first and second upstanding portions are arranged to at least partially enclose the reservoir formed therebetween. For example, the first and second upstanding portions may be arranged to partially enclose the reservoir to form an aperture, for example a slit. In some examples the glazing bar may be arranged to completely enclose the reservoir in one plane (in other words so that the reservoir is bounded on all sides in a plane, such as a cross-section through the glazing bar), but may have an opening in another plane for the injection of intumescent material into the reservoir. The glazing bar may also comprise a deformation or line of weakness (for example in an axis parallel to the longitudinal axis of the glazing bar which may extend between the two panes of glass in use) that may be operable to form an aperture such as a slit into the reservoir to permit the escape of intumescent material from the reservoir in the event of a fire and the intumescent material in the reservoir reaching and/or exceeding a selected threshold temperature. The slit or aperture may be created when the intumescent material expands, or may be created as part of the manufacturing process once the intumescent material has been fed into the reservoir and cured (the intumescent material may be fed into the reservoir in a liquid form and subsequently cure as part of the manufacturing process, such that in use the glazing bar contains a cured intumescent material in the reservoir).

The glazing bar optionally comprises a third upstanding portion between the first and second upstanding portions. The third upstanding portion may be parallel to the first and second upstanding portions. The third upstanding portion separates the reservoir into a first reservoir between the first upstanding portion, the bridging portion and the third upstanding portion; and a second reservoir between the third upstanding portion, the bridging portion and the second upstanding portion. The third upstanding portion may therefore serve as a barrier or membrane to separate the reservoir into the first and second reservoirs. In some examples the third upstanding portion may extend from the bridging portion at a different angle to that which the first and second upstanding portions extend from the bridging portion. The third upstanding portion may be a different length to the first and second upstanding portions, for example the third upstanding portion may be shorter than the first and second upstanding portions. -5 -

An advantage of first and second reservoirs being formed in this way is that they can respectively seal the door either side of the glazing bar and protect the seal (such as the silicone seal) between the glazing bar and the glass pane -so that, for example, even if the pane of glass facing the fire shatters due to the heat, the intumescent seal from the reservoir on the other side can expand and protect the seal on the other side, such that the door is still securely held in position within the door frame. The first and second reservoirs may be configured to contain the same intumescent material.

Optionally, as in the case where there is a single reservoir, the first reservoir may be at least partially enclosed to form a first aperture for the first reservoir between the first upstanding portion and the third upstanding portion; and wherein the second reservoir may be at least partially enclosed to form a second aperture for the second reservoir between the second upstanding portion and the third upstanding portion. The apertures may comprise a slit. As described above for the case where there is a single reservoir, when there are two reservoirs the glazing bar may be arranged to completely enclose each reservoir in one plane (in other words so that each reservoir is bounded on all sides in a plane, such as a cross-section through the glazing bar), but may have an opening such as an aperture in another plane for the injection of intumescent material into each reservoir. The glazing bar may also comprise a deformation or line of weakness for each respective reservoir (for example in an axis parallel to the longitudinal axis of the glazing bar which may extend between the two panes of glass in use) that may be operable to form an aperture such as a slit into each respective reservoir to permit the escape of intumescent material from each respective reservoir in the event of a fire and the intumescent material in the reservoir reaching and/or exceeding a selected threshold temperature. The slit or aperture may be created when the intumescent material expands, or may be created as part of the manufacturing process once the intumescent material has been fed into each reservoir and cured (the intumescent material may be fed into each reservoir in a liquid form and subsequently cure as part of the manufacturing process, such that in use the glazing bar contains a cured intumescent material in each reservoir).

The first and second apertures, for example slits, may therefore be optionally sized such that they are configured to retain the intumescent material at a temperature below a -6 -selected threshold temperature, but when the temperature reaches or exceeds the selected threshold temperature, the apertures permit the intumescent material to expand out through the apertures and to provide a seal between the fire-retardant door and a frame of the door. The threshold temperature may be, for example, equal to or at least 110 degrees centigrade.

The third upstanding portion is optionally shorter than the first and second upstanding portions. This may be because the third upstanding portion is configured to support a draught seal, for example a brush or blade, for example an elastomeric blade. The third upstanding portion may further support a receiving portion for receiving the draught seal, which is optionally configured to extend at least partially in a direction parallel to the bridging portion, transverse to the third upstanding portion, and towards both the first upstanding portion in one direction and towards the second upstanding portion in another direction. The length of the third upstanding portion comprising the receiving portion for receiving a draught seal may be the same length as each of the first and second upstanding portions, such the ends of the first and second upstanding portions and an end of the receiving portion are in line with each other, such that the glazing bar can provide a structure that is flush with an edge of a glass door.

In some examples, the first and second upstanding portions are configured, in use, to extend from the bridging portion towards respective edges of the respective panes of glass, such that the bridging portion, for example inset portions of the bridging portion, are set in from an edge of each pane of glass by the length of the first and second upstanding portions. The length of first and second upstanding portions is less than 20mm, preferably equal to or less than 15mm. Optionally, the first and second upstanding portions extend from the same side of the bridging portion.

According to a second aspect there is provided a fire-retardant glass door comprising a glazing bar as described above.

According to a third aspect there is provided a fire-retardant glass door comprising two panes of glass sandwiching a fire-retardant material therebetween. The fire-retardant glass door comprises a glazing bar along at least one edge of the door separating and -7 -connecting the two panes of glass. The glazing bar comprises two receiving portions each holding a sealant to secure the glazing bar to a respective pane of glass either side of the glazing bar, and a reservoir containing an intumescent material between the two receiving portions. The glazing bar may extend along a longitudinal axis along the edge of the door parallel to the panes of glass of the fire-retardant glass door, and the reservoir and/or the receiving portions may also extend along the longitudinal axis along the edge of the door, optionally along the length of the entire edge of the door. The glazing bar may act to retain the fire-retardant material between the two panes of glass of the fire-retardant glass door. In some examples the fire-retardant glass door may comprise two reservoirs between the two receiving portions, each reservoir containing an intumescent material. The reservoirs may be separated by a barrier or membrane, such as an upstanding portion, such as the third upstanding portion as described below.

Optionally, the glazing bar is configured to retain the intumescent material in the reservoir when the temperature is below a selected threshold temperature, but to permit the intumescent material to escape towards and away from the edge of the fire-retardant glass door when the temperature reaches or exceeds the selected threshold temperature for providing a seal between the edge of the fire-retardant glass door and a frame surrounding the fire-retardant glass door. For example, the intumescent material may escape from the reservoir to seal a gap between the glass door and a doorframe of the glass door.

Optionally, the two receiving portions can be defined by a bridging portion extending between the two panes of glass, and first and second upstanding portions set in from each end of the bridging portion and extending in a direction parallel to each pane of glass and towards the edge of both panes of glass. The first and second upstanding portions are optionally the same length.

The glazing bar optionally comprises a third upstanding portion between the first and second upstanding portions, the third upstanding portion parallel to the first and second upstanding portions. The third upstanding portion may separate the reservoir into a first reservoir containing intumescent material between the first upstanding portion, the bridging portion and the third upstanding portion; and a second reservoir containing -8 -intumescent material between the third upstanding portion, the bridging portion and the second upstanding portion.

The first reservoir may be partially enclosed to form a first aperture for the first reservoir 5 between the first upstanding portion and the third upstanding portion; and wherein the second reservoir may be partially enclosed to form a second aperture for the second reservoir between the second upstanding portion and the third upstanding portion.

The first and second apertures are optionally sized such that they are configured to retain the intumescent material at a temperature below a selected threshold temperature, but when the temperature reaches or exceeds the selected threshold temperature, the apertures permit the intumescent material to expand out through the apertures and to provide a seal between the fire-retardant door and a frame of the door.

Optionally, the third upstanding portion is shorter than the first and second upstanding portions. The third upstanding portion optionally supports a draught seal, for example a brush or blade, for example an elastomeric blade. Optionally, the third upstanding portion may support a receiving portion for receiving the draught seal, wherein the receiving portion for receiving the draught seal optionally extends at least partially in a direction parallel to the bridging portion, transverse to the third upstanding portion, and towards both the first upstanding portion in one direction and towards the second upstanding portion in another direction.

The first and second upstanding portions optionally extend from the same side of the 25 bridging portion towards respective edges of the respective panes of glass, such that the bridging portion is set in from an edge of each pane of glass by the length of the first and second upstanding portions.

According to a fourth aspect there is provided a glazing bar for a fire-retardant glass door. The glazing bar comprises a bridging portion configured to bridge between two panes of glass of the fire-retardant glass door, a first receiving portion arranged, in use, between a first upstanding portion and a first pane of glass, and a second receiving portion arranged, in use, between a second upstanding portion and a second pane of -9 -glass. The first upstanding portion extends from the bridging portion, and the second upstanding portion also extends from the bridging portion and is parallel to and spaced away from the first upstanding portion. The glazing bar also comprises a reservoir arranged between the first and second upstanding portions and configured to receive an intumescent material.

The first and second upstanding portions are optionally substantially parallel to each other and may be positioned in a substantially perpendicular direction from the bridging portion.

Drawings Embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 illustrates a cross-sectional view of an example glazing bar of embodiments of the disclosure; Figure 2 illustrates a perspective view of the example glazing bar shown in Figure 1; Figure 3 illustrates a cross-sectional view of another example glazing bar supporting a draught seal; Figure 4 illustrates a cross-sectional view of the example glazing bar of Figure 3 fitted to a fire door; Figure 5 illustrates a cross-sectional view of the example glazing bar of Figure 1 fitted to a fire door and in proximity to a fire; and Figure 6 illustrates a cross-sectional view of the example glazing bar of Figure 5 25 comprising a seal.

Specific description

Embodiments of the disclosure relate to a glazing bar for use between two panes of glass of a fire-retardant door, and configured to seal the edges of the fire-retardant door in the event of a fire in proximity to the fire-retardant door. Embodiments of the disclosure also relate to a fire-retardant glass door comprising a glazing bar along at least one edge of the door separating and connecting the two panes of glass of the fire-retardant glass door. It will be understood that the glazing bar described herein may be -10 -combined with other commercially available fire glass systems, such as the Promat® SYSTEMGLAS® E1, which comprises two toughened float glass panes encapsulating an intumescent fire-resistant gel.

Figure 1 illustrates a cross-sectional view of an example glazing bar 10. The cross-section is taken in plane orthogonal, in use, to the planes of the two panes of glass between which the glazing bar 1 fits and separates. The glazing bar 1 comprises a bridging portion 10 and first, second and third upstanding portions 20, 22, 24 that are upstanding relative to the same side of the bridging portion 10. The bridging portion 10 has a length, which may be between 10 to 40 mm, which defines the distance between two panes of glass in a fire-retardant glass door when in use. The thickness of the bridging portion may be between 1 mm and 10 mm, for example between 3 mm and 5 mm, preferably around 1.5 mm.

The three upstanding portions 20, 22, 24, extend from the bridging portion 10 in the same direction from the same side of the bridging portion 10, and in the example shown extend parallel to one another perpendicular to the bridging portion 10 (although it will be understood that in other examples the upstanding portions 20, 22, 24 need not be parallel to one another or extended perpendicular to the bridging portion 10, but instead, for example, may be merely transverse to the bridging portion 10).

The third upstanding portion 24 is positioned in a central location along the bridging portion 10 and between the first and second bridging portions 20, 22. The first and second upstanding portions 20, 22 may be spaced away from each end of the bridging portion 10 by a distance a, which defines first and second inset portions at each end of the bridging portion 10. The distance of the first inset portion from a first end of the bridging portion 10 to the first upstanding portion 20 may be equal to a distance of the second inset portion from a second end of the bridging portion 10 to the second upstanding portion 22. The distance separating the first and third upstanding portions 20, 24 and the distance separating the second and third upstanding portions 22, 44 in the example shown is equal and may be equal to a distance a, or may be different to a. The distance a may be between 2 mm and 5 mm, preferably around 3 mm. The distance between the first upstanding portion 20 and the third upstanding portion 24 may be between 3 mm and 6 mm, preferably around 5 mm, more preferably 4.5 mm. The upstanding portions 20, 22 may have a length of between 5 mm and 15 mm, for example around 12 mm. The third upstanding portion 24 may be shorter than the first and second upstanding portions 20, 22, and may have a length of around 9 mm.

The upstanding portions 20, 22, 24 split the bridging portion 10 into separate portions or zones along the bridging portion 10. The first zone or first inset portion of the bridging portion 10 is arranged between a first end of the bridging portion 10 and the first upstanding portion 20. The second zone or first reservoir portion of the bridging portion 10 is arranged between the first upstanding portion 20 and the third upstanding portion 24. The third zone or second reservoir portion of the bridging portion 10 is arranged between the third upstanding portion 24 and the second upstanding portion 22. The fourth zone or second inset portion of the bridging portion 10 is arranged between the second upstanding portion 22 and a second end of the bridging portion 10.

First and second receiving portions 60, 65 of the glazing bar 1 are defined by the first and second inset portions of the bridging portion 10 between respective ends of the bridging portion 10 (i.e. the respective portions of the bridging portion 10 between each end of the bridging portion 10 and the respective first and second upstanding portions 20, 22) and the first and second upstanding portions 20, 22 respectively.

The first upstanding portion 20 has a first transverse portion 40, which in the example shown extends in a direction orthogonal to the first upstanding portion 20 and parallel to the bridging portion 10. The first transverse portion 40 may extend in a direction towards the second and third upstanding portions 22, 24. The second upstanding portion 22 has an opposing second transverse portion 42 that extends in a direction towards, and in line with, the first upstanding portion 20.

A draught seal receiving portion 45 is supported by the third upstanding portion 24 and is arranged between the first and second upstanding portions 20, 22 at the opposite end of the upstanding portions 20, 22 from the bridging portion 10. The third upstanding portion 24 has a third transverse portion 44, which extends in a direction orthogonal to the third upstanding portion 24 and towards the first and second upstanding portions 20, 22. The -12 -third transverse portion 44 has additional fourth and fifth upstanding portions 46, 48 at respective ends that are parallel to the first and second upstanding portions 20, 22, and form the draught seal receiving portion 45 The fourth and fifth upstanding portions 46, 48 of the third upstanding portion 24 connect to the first and second transverse portions 40, 42 extending respectively from each of the first and second upstanding portions 20, 22 to form two closed reservoirs 30, 35 between the transverse portions 40, 42 the upstanding portions 20, 22, 24 and the bridging portion 10. The first and second transverse portions 40, 42 may extend, for example into the draught seal receiving portion 45, so as to create a T-shaped cross-sectional area of the draught seal receiving portion 45, for receiving and retaining a draught seal as shown in Figures 3 and 4 and as described below.

A first reservoir 30 is arranged between: the first reservoir portion of the bridging portion 10, the first upstanding portion 20, the first transverse portion 40, the third upstanding portion 24, the third transverse portion 44, and the fourth upstanding portion 46. A second reservoir 35 is arranged between: the second reservoir portion of the bridging portion 10, the second upstanding portion 20, the second transverse portion 42, the third upstanding portion 24, the third transverse portion 44, and the fifth upstanding portion 48.

The first and second reservoirs 30, 35 are separated by the third upstanding portion 24. The reservoirs 30, 35 may have a cross-sectional area of between 40 mm2 and 55 mm2, for example around 45 mm2.

The first, second and third upstanding portions 20, 22, 24 may have a thickness (in a direction orthogonal to the panes of glass of the fire-retardant glass door, in use) that is less than that of the bridging portion 10, for example between 0.5 mm and 2 mm, preferably around 1 mm. The first, second and third transverse portions 40, 42, 44 may all have the same thickness, for example the same thickness as the first, second and third upstanding portions 20, 22, 24.

The bridging portion 10 provides means for separating the panes of glass of the fire-retardant glass door and for supporting the glazing bar 1 between the panes of glass of the fire-retardant glass door in use. The bridging portion 10 also provides a support for -13 -the first, second and third upstanding portions 20, 22, 24.

Figure 2 illustrates a perspective view of the example glazing bar 1 shown in Figure 1. The glazing bar 1 is configured to extend along at least one edge of a fire-retardant door, in use. The glazing bar 1 is therefore elongate along a longitudinal axis L that, in use, extends between and parallel to the two panes of glass along at least one edge of the fire-retardant door. The longitudinal axis L is orthogonal, in use, to the distance of closest approach between the two glass panes of the fire-retardant glass door, and is parallel, in use, to each pane of glass of the fire-retardant glass door. Because the glazing bar 1 is elongate extending in a longitudinal axis L, in use, between two panes of glass of a fire-retardant glass door, the bridging portion 10, the first, second and third upstanding portions 20, 22, 24, first and second transverse portions 40, 42 and therefore also the draught seal receiving portion 45 and reservoirs 30, 35 are also elongate and extend in the longitudinal axis L. The bridging portion 10, the first, second and third upstanding portions 20, 22, 24, the first and second transverse portions 40, 42 and therefore also the draught seal receiving portion 45 and reservoirs 30, 35 therefore have a minor dimension as taken along a cross-section perpendicular to the longitudinal axis L of the glazing bar 1, and a major (greater) dimension that extends along the longitudinal axis L of the glazing bar 1. The minor dimension of the bridging portion 10 defines, in use, the separation between the two panes of glass of the fire-retardant glass door and corresponds to the distance of closest approach of the two glass panes. It will be understood that the description above in relation to Figure 1 relates to the minor dimensions of the glazing bar 1 as taken along a cross-section of the glazing bar 1 that is, in use, orthogonal to the planes of the two panes of glass of the fire-retardant door.

In the example shown in Figure 1 the reservoirs 30, 35 extend along the entire length of the longitudinal axis L of the glazing bar 1. At at least one end of the glazing bar 1 (along the longitudinal axis L) each of the reservoirs 30, 35 have an aperture. The glazing bar 1 may have apertures at both ends of the glazing bar 1, or only at one end. The aperture may permit a material such as an intumescent material to be fed into each of the reservoirs 30, 35, for example injected into each of the reservoirs 30, 35. It will be understood that the aperture(s) may be sealed in use.

-14 -The first and second receiving portions 60, 65 are each configured to receive a first material, such as a sealant, for example silicone, to secure the glazing bar 1 to respective panes of glass 70, 75 either side of the glazing bar 1 when the glazing bar 1 is positioned between the glass panes 70, 75 of a fire-retardant door. The reservoirs 30, 35 are each arranged to receive a second material such as an intumescent material, for example Ammonium Phosphate, Lithium Phosphate, Sodium Silicate and/or Graphite. The intumescent material may be received in the reservoirs 30, 35, and then optionally treated, for example cured. The first and second materials are kept separate from one another by the first, second and third upstanding portions 20, 22, 24.

The first and second transverse portions 40, 42 supported by the first and second upstanding portions 20, 22, are configured to partially enclose the area between the upstanding portions 20, 22, and in some examples comprise an aperture formed by a slit in each of the first and second transverse portions 40, 42 (not shown in Figures 1 to 4 but shown in Figures 5 and 6). In the example shown in Figures 1 to 4, a slit may be put into each transverse portion 40, 42 after the intumescent material has been received and cured in the reservoirs 30, 35. A first slit, forming a first aperture, is arranged on first transverse portion 40 between the first upstanding portion 20 and the fourth upstanding portion 46 of the draught seal receiving portion 45. A second slit, forming a second aperture, is arranged on the second transverse portion 42 between the second upstanding portion 22 and the fifth upstanding portion 48 of the draught seal receiving portion 45. The first and second apertures extend the length of the glazing bar in the longitudinal axis L such that, in use, intumescent material can escape from the reservoirs along the length of the glazing bar 1 (along the longitudinal axis L) to provide a seal between the entire edge of the door and a doorframe.

The draught seal receiving portion 45, defined by the first, second and third transverse portions 40, 42, 44, and the fourth and fifth upstanding portions 46 and 48, is arranged to receive a draught seal 50, for example a brush or a blade, for example an elastomeric blade or other suitable draught seal. The first and second transverse portions 40, 42 comprise protruding portions that protrude into the draught seal receiving portion 45 so as to form the T-shaped cross-section of the draught seal receiving portion 45 as described above. The first and second transverse portions 40, 42 (and therefore the -15 -protruding portions of the first and second transverse portions 40, 42) are supported by the third transverse portion 44 coupled to the third upstanding portion 24 via the fourth and fifth upstanding portions 46, 48 of the draught seal receiving portion 45. The T-shaped cross-section allows a draught seal 50 to be disposed along the length on the glazing bar and constrained to remain within the draught seal receiving portion 45 of the glazing bar by the protruding portions of the first and second transverse portions 40, 42. The protruding portions of the first and second transverse portions 40, 42 therefore form a lip or flange configured to retain the draught seal 50 within the draught seal receiving portion 45.

Figure 3 illustrates a cross-sectional view of another example glazing bar la supporting a draught seal 50. The draught seal 50 may have a length that extends from between the draught-seal receiving portion 45 of the glazing bar la and a doorframe; across a gap created by the door and the doorframe. The draught seal 50 may be a brush-like or flexible rubber-like material that has degree of flexibility that allows easy opening and closing of the door but also acts to at least partially close or protect the gap between the door and the doorframe when the door is closed.

The glazing bar 1, la described above may be inserted along at least one edge of a fire-retardant door to protect the door from damage caused by fire. The glazing bar 1, 1a may also act to retain a fire-retardant material between two panes of glass of a fire-retardant glass door, as well as to separate the two panes of glass from each other and to secure them together.

Figure 4 illustrates a cross-sectional view of the example glazing bar 1 a of Figure 3 fitted to a fire door as viewed in plane perpendicular to the planes of the panes of glass forming the fire-retardant glass door. The bridging portion 10 is located, in use, between the panels of a fire-retardant glass door, for example wherein the panels comprise two panes of glass 70, 75 as shown in Figure 4. The bridging portion 10 is configured to extend between and fit snugly to each of the glass panes 70, 75 and is arranged, once the glazing bar 1 a has been sealed to each of the glass panes 70, 75, to form a fixed connection to the fire-retardant door such that the glazing bar maintains a steadfast position along the edge of the door to which it is fitted. In the example shown, the first -16 -and second receiving portions 60, 65 attach the glazing bar la to the first and second glass panes 70, 75 respectively via a sealant received by the receiving portions 60, 65. The sealant attaches the glass panes 70, 75 to the glazing bar 1a individually and independently of each other, which can improve the performance of the fire-retardant door.

Figure 5 illustrates a cross-sectional view of the example glazing bar 1 of Figure 1 fitted to a fire door and in proximity to a fire 90, and Figure 6 illustrates a cross-sectional view of the example glazing bar 1 of Figure 5 comprising a seal 95 between the glazing bar and a door frame. The cross-sections of both Figures 5 and 6 are taken in a plane perpendicular to the planes of the panes of glass forming the fire-retardant glass door.

In use, as illustrated for example in Figures 4 to 6, the glazing bar 1, la is disposed between panes of glass 70, 75 of a fire-retardant glass door. If there is a fire 90, the intumescent material heats up and expands. The intumescent material that fills the reservoirs 30, 35 expands when it reaches a selected threshold temperature, for example of 110 degrees centigrade or over. The glazing bar 1 is configured to retain the intumescent material in the first and second reservoirs 30, 35 when the temperature is below a selected threshold temperature, but to permit the intumescent material to escape towards and away from the edge of the fire-retardant glass door when the temperature reaches or exceeds the selected threshold temperature for providing a seal 95 between the edge of the fire-retardant glass door and a frame 80 surrounding the fire-retardant glass door. The slits in the transverse portions 40, 42 permit the intumescent material to escape from the glazing bar 1, la when the threshold temperature of the intumescent material is reached in a defined location that ensures that a seal 95 is made. The intumescent material forms a seal 95 that provides an improved seal, for example against gas and smoke, compared to the draught seal 50 illustrated in Figures 3 and 4.

Although the glazing bar 1, 1a shown in Figures 4 to 6 is shown as being inset or recessed from an edge of the door/from the edges of the panes of glass 70, 75, it will be understood that in other examples an edge of the glazing bar 1, la (such as the ends of the upstanding portions 20, 22 and optionally the draught seal receiving portion 45) may be configured, in use, to be flush with the edges of each of the panes of glass 70, 75 of -17 -the door.

The thickness of the upstanding portions 20, 22, 24 (as taken in the cross-sectional direction orthogonal to the planes of the panes of glass in use and orthogonal to the 5 longitudinal axis L of the glazing bar) is enough to maintain strength under the conditions caused by a fire to keep the separate portions of the glazing bar separate, whilst being thin enough to enable the reservoirs 30, 35 to receive a minimum volume of intumescent material that, when heated to above a threshold temperature will be capable of forming a suitably secure seal between the door and the door frame 80. There must also be 10 enough space provided by the receiving portions 60, 65 to provide enough sealant to seal the glazing bar 1, 1a to the panes of glass 70, 75. The glazing bar 1, 1a, and components thereof (such as the upstanding portions 20, 22, 24) may be made from a metal such as aluminium.

In the event of a fire in proximity to the door, one of the glass panes 70 on the side of the door that is being attacked by flames during the fire may be smashed/shatter and consequently become loose from the fire-retardant door. If a seal 95 has been formed between the door and the doorframe 80 by the intumescent material from the reservoir(s) 30, 35, the sealant provided between the other glass pane and the glazing bar 1 should not be compromised by the loosened pane of glass 70 such that the unaffected glass pane 75 may remain in position and prevent the fire 90 from spreading as quickly and may also prevent smoke from getting through the gap between the door and the doorframe 80.

Although in the examples shown above the glazing bar 1, 1a comprises three upstanding portions 20, 22, 24, it will be understood that in other examples the glazing bar 1, la may only comprise two upstanding portions, such as the first and second upstanding portions 20, 22 such that only one reservoir is formed. In such examples, the reservoir may comprise one or more apertures such as slits for the intumescent material to escape from in the case of fire. In some examples, the aperture may be larger than a slit, for example a hole.

Although in the example shown in and described above with reference to Figures 1 to 3, -18 -a slit may be put into each of the first and second transverse portion 40, 42 after the intumescent material has been received and cured in the reservoirs 30, 35, it will be understood that in other examples a physical slit or aperture need not be formed. For example, each of the first and second transverse portions 40, 42 may be provided with a deformation such as a line of weakness, through which the intumescent material can escape (for example by causing the deformation or line of weakness to break) in response to the temperature of the intumescent material reaching a threshold temperature, such as equal to or at least 110 degrees centigrade.

The draught seal 50 is an optional feature of the glazing bar 1, as well as the draught seal receiving portion 45 of the glazing bar 1 configured to receive the draught seal 50. It will be appreciated from the discussion above that the embodiments shown in the Figures are merely exemplary, and include features which may be generalised, removed or replaced as described herein and as set out in the claims.

In the context of the present disclosure other examples and variations of the apparatus and methods described herein will be apparent to a person of skill in the art.

Claims

-19 -CLAIMS: 1. A glazing bar for a fire-retardant glass door, the glazing bar comprising: a bridging portion configured to bridge between two panes of glass of the fire-5 retardant glass door; a first upstanding portion and a second upstanding portion extending from the bridging portion wherein the first and second upstanding portions are set in from each end of the bridging portion for receiving a sealant to secure the glazing bar to the respective panes 10 of glass; and wherein the first and second upstanding portions are arranged to form a reservoir therebetween for holding an intumescent material.
2. The glazing bar of claim 1 wherein the upstanding portions extend from same side 15 of bridging portion.
3. The glazing bar of any previous claim wherein the upstanding portions are configured to extend in a direction parallel to the panes of glass
4. The glazing bar of any previous claim wherein the glazing bar is configured to receive a sealant to secure the glazing bar to the respective panes of glass in respective receiving portions defined by the respective first and second upstanding portions, the respective glass panes and respective inset portions of the bridging bar.
5. The glazing bar of any previous claim wherein the first and second upstanding portions are arranged to partially enclose the reservoir formed therebetween.
6. The glazing bar of any of the previous claims wherein the first and second upstanding portions are the same length.
7. The glazing bar of any previous claim wherein the glazing bar comprises a third upstanding portion between the first and second upstanding portions, the third upstanding portion parallel to the first and second upstanding portions, the third -20 -upstanding portion separating the reservoir into: a first reservoir between the first upstanding portion, the bridging portion and the third upstanding portion; and a second reservoir between the third upstanding portion, the bridging portion and 5 the second upstanding portion.
8. The glazing bar of claim 7 wherein the first reservoir is partially enclosed to form a first aperture for the first reservoir between the first upstanding portion and the third upstanding portion; and wherein the second reservoir is partially enclosed to form a second aperture for the second reservoir between the second upstanding portion and the third upstanding portion.
9. The glazing bar of claim 8 wherein the first and second apertures are sized such that they are configured to retain the intumescent material at a temperature below a selected threshold temperature, but when the temperature reaches or exceeds the selected threshold temperature, the apertures permit the intumescent material to expand out through the apertures and to provide a seal between the fire-retardant door and a frame of the door.
10. The glazing bar of any of claims 7 to 9 wherein the third upstanding portion is shorter than the first and second upstanding portions.
11. The glazing bar of any of claims 7 to 10 wherein the third upstanding portion is configured to support a draught seal, for example a brush or blade, for example an elastomeric blade.
12. The glazing bar of claim 11, wherein the third upstanding portion supports a receiving portion for receiving the draught seal.
13. The glazing bar of claim 12 wherein the receiving portion for receiving the draught seal is configured to extend at least partially in a direction parallel to the bridging portion, transverse to the third upstanding portion, and towards both the first upstanding portion -21 -in one direction and towards the second upstanding portion in another direction.
14. The glazing bar of any of the previous claims wherein the first and second upstanding portions are configured, in use, to extend from the bridging portion towards respective edges of the respective panes of glass, such that the bridging portion is set in from an edge of each pane of glass by the length of the first and second upstanding portions.
15. A fire-retardant glass door comprising a glazing bar according to any of the 10 previous claims.
16. A fire-retardant glass door comprising two panes of glass sandwiching a fire-retardant material therebetween; wherein the fire-retardant glass door comprises a glazing bar along at least one 15 edge of the door separating and connecting the two panes of glass; and wherein the glazing bar comprises two receiving portions each holding a sealant to secure the glazing bar to a respective pane of glass either side of the glazing bar, and a reservoir containing an intumescent material between the two receiving portions.
17. The fire-retardant glass door of claim 16 wherein the glazing bar is configured to retain the intumescent material in the reservoir when the temperature is below a selected threshold temperature, but to permit the intumescent material to escape towards and away from the edge of the fire-retardant glass door when the temperature reaches or exceeds the selected threshold temperature for providing a seal between the edge of the fire-retardant glass door and a frame surrounding the fire-retardant glass door.
18. The fire-retardant glass door of claim 16 or 17, wherein the two receiving portions are defined by a bridging portion extending between the two panes of glass, and first and second upstanding portions set in from each end of the bridging portion and extending in 30 a direction parallel to each pane of glass and towards the edge of both panes of glass.
19. The fire-retardant door of any of claims 16 to 18 wherein the first and second upstanding portions are the same length.-22 -
20. The fire retardant glass door of claim 18 or claim 19 wherein the glazing bar comprises a third upstanding portion between the first and second upstanding portions, the third upstanding portion parallel to the first and second upstanding portions, the third 5 upstanding portion separating the reservoir into: a first reservoir containing intumescent material between the first upstanding portion, the bridging portion and the third upstanding portion; and a second reservoir containing intumescent material between the third upstanding portion, the bridging portion and the second upstanding portion.
21. The fire-retardant door of claim 20 wherein the first reservoir is partially enclosed to form a first aperture for the first reservoir between the first upstanding portion and the third upstanding portion; and wherein the second reservoir is partially enclosed to form a second aperture for 15 the second reservoir between the second upstanding portion and the third upstanding portion.
22. The fire-retardant door of claim 21 wherein the first and second apertures are sized such that they are configured to retain the intumescent material at a temperature below a selected threshold temperature, but when the temperature reaches or exceeds the selected threshold temperature, the apertures permit the intumescent material to expand out through the apertures and to provide a seal between the fire-retardant door and a frame of the door.
23. The fire-retardant door of any of claims 20 to 22 wherein the third upstanding portion is shorter than the first and second upstanding portions.
24. The fire-retardant door of any of claims 20 to 23 wherein the third upstanding portion supports a draught seal, for example a brush or blade, for example an 30 elastomeric blade
25. The fire-retardant door of claim 24 wherein the third upstanding portion supports a receiving portion for receiving the draught seal.-23 -
26. The fire-retardant door of claim 25 wherein the receiving portion for receiving the draught seal extends at least partially in a direction parallel to the bridging portion, transverse to the third upstanding portion, and towards both the first upstanding portion 5 in one direction and towards the second upstanding portion in another direction.
27. The fire-retardant door of any of the previous claims wherein the first and second upstanding portions extend from the same side of the bridging portion towards respective edges of the respective panes of glass, such that the bridging portion is set in from an 10 edge of each pane of glass by the length of the first and second upstanding portions.
28. A glazing bar for a fire-retardant glass door, the glazing bar comprising: a bridging portion configured to bridge between two panes of glass of the fire-retardant glass door; a first receiving portion arranged, in use, between a first upstanding portion and a first pane of glass, wherein the first upstanding portion extends from the bridging portion; a second receiving portion arranged, in use, between a second upstanding portion and a second pane of glass, wherein the second upstanding portion extends from the bridging portion and is parallel to and spaced away from the first upstanding portion; 20 and a reservoir arranged between the first and second upstanding portions and configured to receive an intumescent material.