GB2306994A

GB2306994A - Compound door frame with core sections filled with a heat absorbing material

Info

Publication number: GB2306994A
Application number: GB9621391A
Authority: GB
Inventors: Louis Francis William Hartin; Arthur Phillips
Original assignee: Shapland and Petter Ltd
Current assignee: Shapland and Petter Ltd
Priority date: 1995-11-10
Filing date: 1996-10-14
Publication date: 1997-05-14
Also published as: GB9621391D0

Abstract

A door frame assembly with fire resisting properties includes first and second frame sections 18, 20 which fit over respective sides of a partition wall, in which a metal stud 14 with an infill 16 of timber or similar material is provided. The first frame section 18 is filled with, or fitted over a subframe or frame lining filled with, timber or similar material. The second frame section 20 is filled with, or fitted over a subframe or frame lining filled with, a cementitious grout. The first and second frame sections provide enhanced fire resisting qualities to the door frame assembly. Also disclosed is a door frame assembly comprising an enclosed box frame, filled with a cementitious grout.

Description

DOOR FRAME The present invention relates to a door frame for a wood door.

Wood doors are often required to be hung on a steel frame as steel is often considered to be more durable and less susceptible to water damage. However, as fire resisting assemblies, steel frames with wood doors are notoriously unsatisfactory because of the differing behaviour of wood and steel when heated (for example to temperatures of approximately 9000C and above). More specifically, during heating, the steel will grow and distort, whereas the wood will remain more stable and will not grow appreciably. The difficulty is increased when such assemblies are installed in metal stud partitions, as they commonly are, because the partition is itself very unstable when heated.

Known steel frames also perform unsatisfactorily with wood doors as the steel will conduct heat from the face of the door exposed to fire to the unexposed face, causing the latter to ignite.

Steel frames are most often used as a "first fix" item in which a wall of block or brick is built into the back of the U-section frame with voids being filled with cement as building proceeds. On the other hand, with metal stud partitions, steel frames cannot be used in this way and are most usually "second fixed", in which case the architrave cannot perform its usual function of obscuring the joint between the frame and wall.

The present invention seeks to provide an improved frame assembly.

According to an aspect of the present invention, there is provided a door frame assembly comprising first and second frame sections each attachable to a respective side of a wall and relative to one another to form an integral frame.

Each frame section is preferably fitted over a subframe or frame lining of wood or alternatively is of hollow box form and filled with a heat absorbing material.

For more prolonged fire resistance at least one of the frame sections may include a hollow box section preferably filled with a heat absorbing material. The material may be cementitious grout. The other frame section may be fitted over a subframe of timber.

The filled box section enclosure can add stability to the frame at high temperatures (such as 9000C and above), in particular to assemblies which are installed into a partition formed of metal studs.

According to another aspect of the present invention, there is provided a door frame assembly comprising one or more frame sections filled with a heat absorbing material.

According to another aspect of the present invention, there is provided a door frame assembly comprising an enclosed box frame section filled with cementitious grout.

An embodiment of the present invention is described below, by way of example only, with reference to the accompanying drawing, in which: Figure 1 is a cross-sectional view from above of an embodiment of door frame assembly; Figure 2 is a cross-sectional view of another embodiment of door frame assembly; and Figure 3 is a cross-sectional view of a third embodiment of door frame assembly.

Referring to Figure 1, the embodiment of door frame assembly shown is shown fitted to a wall formed of two spaced plasterboard sheets 12 fixed to a metal stud 14 in the form of a C-shaped box section. The stud 14 has an infill 16 of timber or similar material. This describes a typical form of metal stud partition.

The metal frame is formed as two half frames 18,20 which are coupled together during installation. This enables the frame to take up any variation, if any, in wall thickness, with the integral architrave performing the usual function.

The first half frame 18 is an elongate member which is substantially J-shaped in transverse cross-section, as will be apparent from Figure 1. Filling the first frame half 18 and extending beyond its front elongate flange 22 is an elongate rectangular frame lining or subframe 24 made of timber, MDF or similar material. A series of apertures in the front flange 22 allows fixing screws 28 to pass through the lining 24 and the metal stud 14 and into the infill 16, thereby to secure the first frame half 18 to the wall.

The second frame half 20 describes a hollow box section filled with a heat absorbing material and includes an outer section 26 equivalent to the first frame half 18, although with an inwardly extending flange 30 protruding from a rear wall 32 thereof.

In the embodiment shown in Figure 1, the second frame half 20 includes an inner section 34 which forms an enclosure 36 between the front and rear walls of the outer section 26. The enclosure is preferably pumped with cementitious grout. This infill acts as a heat sink and prevents heat from transferring through the steel and igniting the unexposed face of the door leaf 50. This enables the frame to impart to the door frame assembly a much enhanced fire resistance and can prevent charring of the lining and heat transmission through the steel. A further advantage of this embodiment is that since it remains relatively cool, the frame does not expand or distort to the same degree as an unfilled frame. As a result, the integrity of the door and frame assembly with respect to penetration of fire around the frame/leaf gap is greatly increased.

The filling also adds rigidity to and reduces distortion of the metal stud 14, thereby enhancing fire resistance of the structure due to the reduction of gaps through which fire can pass.

The second frame half 20 can include mitred joints between the vertical and horizontal elements thereof.

The second frame half 26 also acts as the frame part on which the door 50 is hung.

The extremity of the front wall of the second frame half 26 is also provided with a row of apertures for receipt of screws 40, which also pass into the infill 16. In practice, the width of the front walls of the first and second frame halves 18, 20 is chosen such that they do not touch when fitted to the wall. However, the lining 24 is of a width so as to extend under the apertures for the screws 40, thereby providing a strong connection between the two frame halves 18, 20.

An elongate hollow metal door stop 60 is fitted over the gap between the two frame sections 18, 20 and is secured to the frame by screws 62, for which the front wall of the door stop 60 is provided with apertures 64. The apertures 64 can be covered with any suitable cover for aesthetic purposes.

The metal parts of the frame assembly are preferably of steel or similar material.

It will be apparent from the above that the door and frame assembly can be installed in the conventional manner appropriate to a second fix doorset, in the following manner. Packings 66 are first used to take up space between the lining 24 and the metal stud 14. The door-hanging grout-filled box frame half 20 is then fixed through its flange and through the lining 24 into the wall via the stud 14. The first frame half 18 is then fixed through the lining 24 and into the wall 12, also through the stud 14. In each case, the integral architrave of each frame half 18, 20 is brought to a tight fit to the wall faces 12, thereby taking up any variation in partition thickness. Finally, the door stop 60 is fitted to cover the frame joint and arrest the door 50 in the correct position for latch or lock.

Referring to Figure 2, an alternative embodiment of frame assembly is shown which includes first and second frame sections 70,72 which are usually disposed either side of a wall (not shown). The first and second frames are filled with a subframe or frame lining 74 of timber, MDF or the like. A hollow box section 76 couples first and second frame sections 70,72 to one another. A door 78 of any suitable construction is hinged to the second door frame 72. The door could be a nil fire or a half hour fire door.

Figure 3 shows an embodiment intended to provide high resistance to fire. As will be apparent, the Figure shows two side by side doors, each pivotally coupled to a respective door frame assembly 80,82.

Each frame assembly fits over a wall or other partition 84. The first frame section 86 of each frame assembly is in the form of a metal box section frame filled, in this embodiment, with cementitious grout. The second frame section 88 is hollow and fits over part of the first frame section 86.

It will be apparent that the size of the first frame section 86 is larger than that shown in the previous embodiments, as a result of which it provides greater heat sink capacity. The second frame section 88 does not, therefore, require any infill.

As for the previous embodiments, a box frame section 90 acts as a steel cover overlying the joint between the first and second frame sections 86,88. Screws 92,94 fix the first and second frame sections to one another and to the wall or other partition 84.

Claims

1. A door frame assembly comprising first and second frame sections each attachable to a respective side of a wall and to one another to form an integral frame.

2. A door frame assembly according to claim 1, wherein each frame section is fitted over a subframe or frame lining.

3. A door frame assembly according to claim 2, wherein the subframe or frame lining is of wood, MDF or similar material.

4. A door frame assembly according to claim 2, wherein the subframe or frame lining is of hollow box form and filled with a heat absorbing material.

5. A door frame assembly according to any preceding claim, wherein at least one of the frame sections includes a hollow box section.

6. A door frame assembly according to claim 5, wherein the box section is filled with a heat absorbing material.

7. A door frame assembly according to claim 6, wherein the heat absorbing material is cementitious grout.

8. A door frame assembly comprising one or more frame sections filled with a heat absorbing material.

9. A door frame assembly comprising an enclosed box frame section filled with a cementitious grout.

10. A door frame assembly substantially as hereinbefore described with reference to and as illustrated in Figures 1, 2 or 3 of the accompanying drawings.