GB2226345A

GB2226345A - Structural cam cladding

Info

Publication number: GB2226345A
Application number: GB8830088A
Authority: GB
Inventors: Paul Maniatt
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-12-23
Filing date: 1988-12-23
Publication date: 1990-06-27
Also published as: GB8830088D0

Abstract

There is disclosed a method of applying fire proof cladding around a structural beam (10), in which the cladding comprises a pair of elongate pre-formed components (11) which are capable of being snap-fitted together to form a cladding enclosure around the beam (10), and which is a self-supporting and free standing structure which does not rely upon the structural beam for support, and which defines an air gap between the cladding and the structural beam to provide additional fire retarding properties. <IMAGE>

Description

STRUCTURAL BEAM CLADDING This invention relates to the cladding of structural beams used in buildings, such as columns and horizontal support beams.

In the construction of buildings used by the general public, such as office blocks and supermarkets, it is usual to erect a framework of metal beams and then to mount the structure of the building on the framework. While metal beams are not themselves readily combustable, fire regulations for public buildings require that metal beams should be clad with fire resistant material which can shield the beams from the effects of a fire for a predetermined period, such as one or two hours. These requirements are intended to maintain the structural integrity of a building in which a fire develops for a sufficient period for all of the occupants to leave the building long before there is any risk of collapse of the building by buckling of the beams under the effect of heat and load.The maintenance of the structural integrity of the building for a reasonable period will also assist in fire fighting efforts.

There are a number of existing ways of applying fire resistant cladding to metal beams, and these result in a generally satisfactory finished product, but suffer from the disadvantage that they require a number of separate manual operations to assemble the cladding on the beams, which is a time consuming exercise.

One known method comprises the application of metal gauze around each beam. followed by the application of wet plaster around the beam and so as to embed the gauze which effectively "keys" the plaster cladding to the beam.

Another method involves the use of plasterboard type panels which are assembled in a box-shape around each beam, and are then held together by ties.

Both of these existing methods involve a number of separate manual operations. and the time element of the assembly inevitably is reflected in the costing of the job.

Also, the quality of the job, both from the point of view of technical function and also visual appearance will be dependant to a large extent upon the care and attention given by the persons responsible, and this of course can be a variable factor.

The invention therefore seeks to provide an improved means for applying cladding to a structural beam and which involves the use of pre-formed cladding which can be assembled around a beam in a speedy and reliable manner i.e. applied to the beam in a "dry state".

The invention has been developed primarily in relation to the application of fire-resistant cladding to metal beams, such as columns pillars, beams or lintels, though it should be understood that the invention is not restricted to fire resistant cladding, but may include other forms of cladding, and including ornamental or decorative cladding.

For the purposes of this specification, the reference to fire resistant cladding is intended to include nonflammable material which is capable of withstanding the application of high temperatures generated by a fire for a substantial period e.g. half an hour or more, without serious deterioration or degradation, and so as to shield a beam enclosed by the cladding from the full effects of these high temperatures.

According to one aspect of the invention there is provided a method of applying cladding around a structural beam and comprising snap-fitting two preformed elongate components together to form an enclosure around the beam.

Preferably, the design of the components is such that they form a shelf-supporting and free standing structure when assembled, and which does not rely upon the structural beam for support. By virtue of this arrangement, and air gap is formed between the cladding and the structural beam which will provide additional fire retarding properties.

The snap-fitting together of the components may take place in any convenient manner. Conveniently, each one of the components has a pair of longitudinal coupling edges which mate with corresponding coupling edges of the other of the components. The edges at the opposed ends of the components may be similarly designed for snap-fitting together of assembled cladding components end to end to form a rigid interconnected structure throughout its height.

The engagement between the mating edges of the components is a resiliently deformable arrangement, in that the limbs from which the mating edges project are able to carry out a resilient bending movement as the edges come into engagement and, once the edges are fully in engagement, the resilient bending energy stored in the limbs enables the edges to "snap" fit into a locked position.

Any suitable profile may be provided on the mating edges. such as saw tooth type projections arranged along tapering edges which provide a progressively tighter fit as the mating edges move towards full engagement. However.

many other edge profiles may be adopted. which are capable of permitting the components to be snap-fitted together.

Additionally. it should be mentioned that. when the components are made of plaster. upon heating of the components in a fire the plaster contracts thus tightening and thereby interlocking its edges even further. In addition, the profile is specially designed to incorporate a series of consecutively mating edges so that each longitudinal and vertical unit retains its interlocking properties even during degradation due to heat.

To provide cladding around standard I-beam sections, it is preferred that the two components, when assembled together. form a rectangular box-type enclosure around the I-beam.

Each component may therefore be formed substantially either as a channel comprising a base and a pair of parallel side limbs projecting from the base or a circle cut across its diameter, in which the mating edges are formed along the free edges of the limbs or at the points where the diameter dissects the circular profile. However, other shapes may be adopted for the components, such as one channel section forming three sides of a rectangle to enclose the beam, and a further component in the form of an elongate strip with projections which are engageable with the free edges of the channel shaped component in order to complete the rectangular formation of the enclosure.

Further, the invention should not be considered as restricted to the use of two components only to form an enclosed cladding around a beam, provided only that the components which make up the cladding are capable of snapfitting together to form an enclosure around any particular beam.

Also, other shapes than rectangular enclosures may be formed, including circular cross section cladding.

The preferred material from which the components of the cladding are formed is gypsum, which can be moulded into required shapes for the components, and with appropriate selection of the material and the moulding conditions, it is possible to achieve the formation of suitable profiled edges which can snap fit together without damage to the engaging edges, or to the main body of each component.

A particuarly suitable type of gypsum which may be used in a formation of the components comprises relatively "hard" types of plaster obtainable from British Gypsum and sold under the trade names Cristocal and Cristocast. The use of these hard plasters provides a particularly impact resistant cladding component, when fully dried out, and therefore will be especially useful when mounted on columns or pillars near to floor level, where they are liable to be exposed to impact from time to time. Thus, the support columns in supermarkets are particularly liable to be exposed to damaging impact from supermarket trolleys.

Less hard plasters may be employed in the cladding of pillars and columns in situations where they are unlikely to be exposed to the risk of damaging impact.

When additional fire resistance is required, the plaster components will incorporate any suitable known fire resistant or fire retardant material such as fibreglass strands.

Upon assembly of the cladding component around a beam, by snap-fitting the components together, fine liquid plaster may be poured over the joints between the mating edges of. the components, and also between adjacent cladding assembly, so as to provide a smooth final finish which then only requires painting.

The invention also includes cladding for application around a structural beam and comprising at least two preformed elongate components made of fire resistant material and capable of snap-fitting together to form an enclosure around the beam.

One embodiment of the invention will now be described in detail, by way of example only, with reference to the accompanying drawing, in which: Figure 1 is an exploded view illustrating the manner by which cladding components can be assembled around a structural metal beam to form a cladding enclosure; Figure 2 is a plan view of the two components which can be snap-fitted together to form the cladding enclosure; and.

Figure 3 is a detail illustration of the snap-fitting interengagement between the components.

Referring now to the drawings, there is shown a structural beam in the form of a metal I-beam 10 which may form an upright column or pillar as part of a metal framework of a building, and which requires the application of fireproof cladding thereon, to meet fire regulations. A pair of elongate pre-formed components are provided, one of which is shown and designated by reference 11, and which are capable of being snap-fitted together to form a cladding enclosure around the beam 10. The cladding components 11 are moulded from gypsum, and each takes the form of a channel shape, so that when assembled together they form a box-shaped enclosure surrounding the beam 10.

One preferred material from which the components 11 are made comprises any suitable "hard" plaster, such as those obtained from British Gypsum under the trade mark Cristocal or Cristocast. The use of hard plasters will provide a cladding which is both fire resistant, and also has impact resisting properties, which may be desirable in the cladding of the lower regions of the beam 10 adjacent to a floor.

It has been found surprisingly, that with careful attention in the moulding of the components 11, and provision of suitable snap-fitting mating edges, that two components 11 can be pressed firmly into engagement with each other, one from either side of the beam 10, and then snap-fit into rigid engagement with each other, and without any appreciable damage to the mating edges, or to the main body of the components.

By way of example only, Figure 2 shows a pair of channel shaped components ila and lib each having a base 12, a pair of parallel limbs 13 projecting from the base 12, and free edges 14 of the limbs 13 which are provided with suitable profiles to permit snap-fitting engagement with complementary profiles provided on another component.

By way of example only, the free edges 14 of component ila are provided with inwardly facing saw tooth or curved rib configurations 15 and the free edges 14 of the component lib are provided with complementary configurations 16 facing outwardly, so that the inward configurations 15 of component lla can make resilient snap-fitting engagement with corresponding outward configurations 16 of the other component llb.

In addition, although not shown, the edges at the opposed ends of the components may be designed to be capable of being snap-fitted together to enable assembled cladding components to be coupled together end to end to form a rigid interconnected structure throughout its height. Also, the design of the components is such that they form a self-supporting and free standing structure when assembled, and which does not rely upon the structural beam for support. By virtue of this arrangement, and air gap is formed between the cladding and the structural beam which will provide additional fire retarding properties.

Upon heating of the components, in the event of a fire, the plaster from which they are made contracts thus tightening the interlocking edges even further. In addition, the profile is specifically designed to incorporate a series of consecutively mating edges, so that each longitudinal and vertical unit retains its interlocking properties even during degradation due to heat.

It should be understood that a rectangular box-shaped cladding enclosure around a structural beam represents just one example of a form of enclosure which may be provided within the scope of the invention. Also, when a rectangular enclosure is required, it is not essential for two channel shaped components 11 to be provided, as a single channel shaped component with long parallel limbs to be provided, and a second strip shaped component can complete the rectangular shape, provided that it has depending flanges or projections which are capable of snapfitting into engagement with the free edges of the channel shaped component.

Also, enclosures may be formed from two or more components which can be snap-fitted together, and other shapes than rectangular may be adopted, including circular cross section shapes.

It is envisaged that cladding components assembled to form a cladding enclosure around the structural beam will be particularly suitable in the application of fire resistant cladding to meet fire regulations in public buildings. However, the invention is not restricted to this, and has general application to the application of cladding forming an enclosure snap-fitting around a structural beam, including ornamental or decorative cladding.

Claims

1. A method of applying cladding around a structural beam and comprising snap-fitting to pre-formed elongate components together to form an enclosure around the beam.

2. A method according to Claim 1, in which the design of the components is such that they form a self-supporting and free standing structure when assembled, and which does not rely upon the structural beam for support.

3. A method according to Claim 1 or 2, in which each of the components has a pair of longitudinal coupling edges which mate with corresponding coupling edges of the other of the components in order to snap-fit together.

4. A method according to any one of claims 1 to 3, in which the edges at the opposed ends of the components are designed for snap-fitting together of assembled cladding components end to end to form a rigid interconnected structure throughout its height.

5. A method according to any one of the preceding claims, in which the mating edges of the components are provided with saw tooth type projections arranged along tapering edges which provide a progressively tighter fit as the mating edges move towards full engagement.

6. A method according to any one of the preceding claims, in which the components are made of plaster so that, upon heating of the components in a fire, the plaster contracts thus tightening and thereby interlocking its edges even further.

7. A method according to Claim 6, in which the mating edge profiles incorporate a series of consecutively mating edges so that each longitudinal and vertical unit retains its interlocking properties even during degradation due to heat.

8. A method according to any one of the preceding claims, in which the two components, when assembled together, form a rectangular box-type enclosure around an I-beam.

9. A method according to Claim 8, in which each component is formed either as a channel comprising a base and a pair of parallel side limbs projecting from the base or a circle cut across its diameter, and in which the mating edges are formed along the free edges of the limbs or at the points where the diameter bisects the circular profile.

10. A method according to any one of the preceding claims, in which the components of the cladding are made of gypsum.

11. A method according to Claim 10, in which the gypsum incorporates fire resistant or fire retardent material.

12. A method according to any one of the preceding claims, in which fine liquid plaster is poured over the joints between the mating edges of the components after the latter have been snap-fitted together.

13. A method according to Claim 1 and substantially as hereinbefore described with reference to, and as shown in the accompanying drawings.

14. Cladding for application around a structural beam and comprising at least two pre-formed elongate components made of fire resistant material and capable of snap-fitting together to form an enclosure around the beam.