GB2072046A

GB2072046A - Flat support material carrying a coating, process for protecting objects from the effect of fire and use of the flat support material for this purpose

Info

Publication number: GB2072046A
Application number: GB8106267A
Authority: GB
Original assignee: Herberts GmbH
Current assignee: Axalta Coating Systems Germany GmbH and Co KG
Priority date: 1980-03-25
Filing date: 1981-02-27
Publication date: 1981-09-30
Also published as: NL8100661A; ES500257A0; SE8101845L; DE3011453A1; FR2479307A1; DK133781A; BE887978A; ES8206720A1

Abstract

The invention provides a coated support material with a plurality of empty interstitial spaces wherein the coating comprises a mass of fire protective material able to form a barrier layer, the empty interstitial spaces of the support material are of such a size that they become closed as a result of formation of the barrier layer, and the total surface of the empty interstitial spaces constitutes at least 10% of the total surface.

Description

SPECIFICATION Flat support material carrying a coating, process for protecting objects from the effect of fire and use of the flat support material for this purpose The present invention relates to a flat support material having a coating, a process for protecting objects against the effects of fire and the use of the flat support material for this purpose.

A very wide range of articles must be protected against the effects of fire. In many cases this is done by providing the object to be protected with a coating of a fire protecting mass, which in the case of fire forms a barrier layer which thus protects the object to be protected for a certain period of time from becoming destroyed as a result of excess heat or fire. Masses for producing fire protective coatings of this type are known in a whole range of compositions. The requirements to be met in each case, which are partly established by Law, require that the fire protection in this sense be of various durations, e.g., of at least 10 minutes. It is obviously desirable, and additional there is a great need for this, to increase the length of time during which such fire protection is effective.An important group of objects which have to be protected are electrical cables and conduits, e.g., in ships, power supply devices, buildings, tunnels of underground railways and the like. It would be possible to increase the fire protection of cables and conduits of this type and other objects which have to be particularly well protected by surrounding these with a constructional material, non-flammable casings and the like.

The disadvantage of such an arrangement resides in the fact that then the object, e.g., cables, are not readily accessible, that little or no ventilation takes place, and that such protective casings are of appreciable weight.

The present invention has the aim of providing fire protection for objects, which is superior to the fire protection provided by a coating of a fire-protective mass, and which, on the other hand, does not suffer from the disadvantages discussed above.

The object of the present invention accordingly is a flat support material with a plurality of empty interstitial spaces distributed statistically and a coating, which is characterised in that the coating comprises a mass of fire-protective material able to form a barrier layer, the empty interstitial spaces of the support material are of such a size that they become closed as a result of formation of the barrier layer, and the total surface of the empty interstitial spaces constitutes at least 10% of the total surface.

The invention further provides a process for protecting objects against the effects of fire by enveloping the object, which is characterised in that the envelope is made up by at least 30% of the above defined flat support material, and in that the flat support material is arranged at a distance, which is advantageously at least 30mm and at the most 1 50mm, from the object to be protected.

The present invention further has as it object the use of the above-defined flat support material for protecting objects, particularly cables and/or conduits, against the effects of fire, by enveloping them with said material.

A very wide range of objects can be protected from the effects of fire by employing the invention.

The invention can be used with particular advantage for protecting electric cables and conduits. These generally run along walls or under roofs of rooms, including tunnels. In some cases they run in cable shafts. The cabes or conduits are sometimes arranged directly on these building components; sometimes they run through holders with a certain amount of spacing. According to the invention, the sides which are still free are covered with the flat support material having the empty interstitial spaces as defined above. In order to obtain an adequate degree of fire protection, at least 30% of the total peripheral surface should be covered with the support material according to the invention. The size of such a surface essentially depends on the way in which the object to be protected is arranged.When, for example, cabes run in the corner defined between a wall and the roof, the cables are protected on two sides by these walls, or ceiling respectively, and the two open sides, considering the arrangement in cross-section, would be formed by the support material according to the invention. It is of course possible, according to the invention, to envelope the objects to be protected against the effects of fire completely with the support material according to the invention. For example, freehanging cable troughs with the cables lying in them could be completely surrounded on all sides with the support material according to the invention.

When, for example, cables are laid in a shaft, which is surrounded on three sides by walling, only one open side remains, which constitutes 25% of the total outer surface, and which is covered off using the support material according to the invention. The objects to be protected from fire could obviously also be completely surrounded by the support material according to the invention, or they could be covered by an amount of at least 30% with the support material according to the invention and have the remainder covered with some other fire protective material.

Fire protective masses which are known per se can be used to provide the fire protective coating which forms the barrier layer.

The flat support material having empty interstitial spaces according to the invention is advantageously made of metal. Examples of such support materials are expanded metal, perforated metal sheet, wire mesh, etc. The size of the empty interstitial spaces of the support material is so arranged that they become closed, in the case of fire, by formation of the barrier layer from the mass forming the fire protective coating. It is obvious thatthe thickness of the mass of fire protective coating should be selected so that the empty spaces provided in the support material become closed within a short period of time which essentially is determined by the requirements of Law. The closing off of the interstitial spaces occurs as a result of the formation of the barrier layer resulting from the effects of fire and heat on the mass forming the fire protective coating.Such procedures are known per se. As a general rule, it has been found advantageous for the empty interstitial spaces to have a size of 1cm2 maximum, preferably a maximum of 0.8cm2, and particularly preferred a maximum of 0.5cm2. They may take various geometrical shapes, i.e., they may be round, quadratic, rectangular, etc. They may also, for example in the case of wire mesh, be of other shapes. The essential thing is that the shape is such that, in the case of fire, the barrier layer fills all the empty interstitial spaces, so that an un-interrupted surface is formed, which protects the objects requiring protection from the fire or from the effects of heat.

The flat support material may also be a coarse mesh fabric in a non-flammable material or a material which only burns with difficulty, such as for example a glass fibre cloth.

The size of the individual empty interstitial spaces in the flat support material is advantageously at least 1 mm2, preferably at least 4mm2, and particularly preferably at least 1 0mm2.

As has already been discussed, the total surface area ofthe empty interstitial spaces should make up at least 10% of the total surface area of the flat support material. It is preferable for the total surface area of the empty interstitial spaces to make up at least 30% of the total surface area of the flat support material. The top limit for the total surface area of the empty interstitial spaces is determined by the stability of the support material and by the suitable amount of fire protective mass, which must be introduced in order for the empty spaces to become closed off as a result of formation of the barrier layer when fire occurs.In practice, it has been found that the total surface area of the empty interstitial spaces should at the most make up 95%, preferably a maximum of 80% of the total surface area of the flat support material.

The empty interstitial spaces provide good ventilation of the object to be protected. This is particularly important in the case of, e.g. electrical cables or conduits, where a not inconsiderable amount of heat is produced when high currents are flowing, which must be removed by adequate ventilation.

All the data concerning the size of the individual empty spaces and the amount of the total surface of the empty interstitial spaces are based on a coated flat support material according to the invention.

The objects which are to be protected from fire, e.g., cables, may obviously have their own coating or outer layer made up by a fire protective mass which forms a barrier layer, and this coating andlor protective layer can, in a known manner, be provided with a non-foaming coating varnish.

In order to obtain this desired protection from fire it is essential for the support material according to the invention to be arranged at a certain distance from the object which is to be protected. This preferably amounts to at least about 40mm and particularly preferably to at least about 50mm. At the maximum it should amount to 150mm, preferably a maximum of 1 20mm and particularly preferably a maximum of 100mm. The exact spacing can be selected in each individual case as a function of the actual conditions at the point of application and as a function of the desired time for which fire protection is to be effective.

In order to provide a value for the time of protection against fire or heat, modeis, e.g., consisting of cables optionally coated with a fire protective mass, which are covered by the flat support material according to the invention, are subject to the effect of flame using the unit temperature curve according to DIN 4102, whilst at the same time, using a suitable measuring arrangement, values for the insulation resistance of the conductor of the cable under investigation are provided.

The time of protection may for example be the time expressed in minutes during which such a testing arrangement still fulfills its electrical supply - function.

The present invention will now be described in greater detail with reference to the attached drawing.

In the Figures the same parts are indicated by the same reference numerals.

Figure 1 is a diagrammatical view of a flat support material according to the invention.

Figure 2 is a cross-section through the same at the point indicated by the arrows.

Figure 3 is a diagrammatical view of the arrangement which is discussed in example 1, and Figure 4 shows the arrangement discussed in example 2.

In Figure 1, the coated grid members of the flat support material are indicated by 1, and these form the empty interstitial spaces 2. In Figure 2 it can be seen that the coated grid members consist of a core 1 a, e.g., of wire, textile fibres or glass fibres, which have a coating 1 b of a mass of fire protective material which is able to form a barrier layer.

In Figure 3, cables 4 are shown attached to a tunnel wall 6. The roof of the tunnel is shown at 7.

The flat support material 3 according to the invention is, using attaching members 5, arranged at a spacing, which in this case is advantageously about 35mm from the thickest cable.

Figure 4 is a diagrammatical cross-section through the testing arrangement described in Example 2. The wall 6, which is covered by the roof 7, is provided with an opening 8. Cables 4 run along the opening 8.

The flat support material 3 according to the invention having its solid grid members 1 and empty interstitial spaces 2 is arranged at a distance from the cable 4 and closes the whole of the opening 8 off.

The area of the fire is located on the side at which a flame 10 is shown diagrammatically. On the opposite side to the fire, the opening 8 is closed off by means of a slab 9 of rock wool. The temperatures are measured at the points of measurement 11.

Example 1 A set of cables, which were laid in the usual way on the wall of an underground railway shaft, was covered with a flat support material in such a way that it was spaced by about 35mm from the cables or respectively, their attachment members. The support material contained empty spaces each of about 1cm2 in size. It was coated with a fire protective mass able to form a barrier layer, which in the case of fire, foamed so as to occupy 35 times its normal volume, as a result of which the interstitial spaces became filled with insulating foam, and had an outer coating of a non-foaming varnish. The cable itself as well as its attachment members were also coated with the fire protective mass and the varnish outer coating.

When an investigation of the effects of fire was carried out according to DIN 4102, the time of protection amounted to at least 30 minutes.

Example 2 Fire proof closing off a ventilated wall (or roof) opening, which had cables running along it.

The testing arrangement was built in the form of a wall element and was covered off, on the opposite side to the fibre, with slabs of rock wool, in order to create the most unfavourable testing conditions as a result of the accummulation of heat.

The opening provided a clear space of size 50 x 50cm. It had several cables passing along it of the types NYM and NYY, of 4 x 1 0mm2 diameter, which were not provided with additional fire protection. At a distance of about 35mm from the cables, a flat support material coated with a fire protective mass, according to the invention, was arranged, the size of the openings in it, i.e., the empty interstitial spaces, being in each case about 1.2cm2 in size.

The fire test was carried out according to DIN 4102: the required time of protection was 30 minutes, expressed as a temperature limit of 200"C on the outer side of the cables. The temperatures measured remained at all points of measurement below 200"C until a time of 57 minutes had elapsed.

Claims

1. Flat support material with a plurality of statistically distributed, empty interstitial spaces and with a coating, characterized in that the coating comprises a mass of fire-protective material able to form a barrier layer, the empty interstitial spaces of the support material are of such a size that they become closed as a result of formation of the barrier layer, and the total surface of the empty interstitial spaces constitutes at least 10% of the total surface.

2. Flat support material according to Claim 1, characterized in that the total surface of the empty interstitial spaces constitutes at least 30% of the total surface.

3. Flat support material according to Claims 1 or 2, characterized in that the total surface of the empty interstitial spaces constitutes at the maximum 80% of the total surface.

4. Flat support material according to any one of Claims 1 to 3, characterized in that the size of the individual empty interstitial spaces of the flat support material is between 1 mm2 and 1cm2.

5. Flat support material according to any one of Claims 1 to 4, charåcterized in that the size of the individual empty spaces of the flat support material is between 10mm2 and 0.5cm2.

6. Flat support material according to any one of Claims 1 to 5, characterized in that the flat support material is made of metal.

7. Flat support material according to Claim 6, characterized in that the flat support material is an expanded metal.

8. Flat support material according to any one of Claims 1 to 5, characterized in that the flat support material is a glass fibre fabric.

9. Process for protecting objects against the effects of fire by enclosing said objects in an envelope, characterized in that at least 30% of said envelope is made up of a flat support material according to Claims 1 to 8, and in that the flat support material is arranged at a distance of from 30mm to 1 50mm, from the object to be protected.

10. Process according to Claim 9, characterized in that the objects to be protected are cables and/or conduits.

11. Process according to Claims 9 or 10, characterized in that the flat support material is at a distance of from 40mm to 1 20mm from the objects.

12. Process according to any one of Claims 9 to 11, characterized in that the flat support material is at a distance of from 50mm to 100mm,from the objects.

13. Use of the flat support material according to Claims 1 to 8 for protecting objects, in particular electrical cables and/or conduits, against the effects of fire, by surrounding them with said material.