GB2034535A

GB2034535A - Electric cable duct having fire protection provision

Info

Publication number: GB2034535A
Application number: GB7929551A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-09-11
Filing date: 1979-08-24
Publication date: 1980-06-04
Also published as: DE2839396C3; SE7906891L; DK148246C; AT370261B; DE2839396B2; DK375679A; BE878643A; FR2435844B1; GB2034535B; NL7906406A; FR2435844A1; IT1123111B; CH646549A5; ATA595179A; DK148246B; IT7925609A0; DE2839396A1; SE425448B

Abstract

A cable duct (1) for electric cables (19) comprises a channel (14) of double- walled construction, having a cover (2). To prevent overheating of the cables in the normal course, ventilation openings (10) are provided, offset in the inner and outer walls (5, 6 and 7, 8) respectively of the channel, to prevent flames reaching the cables, in the event of fire. The inner and/or outer walls of the channel, and the cover, are coated on their insides and/or their outsides with a coating of a material which foams when heated by the flames to form heat insulating layers enclosing the cables. Materials are exemplified. In this manner, vital services, powered by the cables, are protected. <IMAGE>

Description

SPECIFICATION Electric cable duct having fire protection provision The invention relates to an electric cable duct having a fire responsive provision for protecting the cables.

In known cableways or ducts providing fire protection, separate linings or asbestos or the like fireproof material cover the inside of the duct and in this manner, in the case of a fire, it is intended to prevent the fire or the heat from destroying the cables or at least damaging them to such an extend that current supply to vital units, for example in hospitals, fails through short-circuiting. such internal lining, however, leads to pour ventilation in the interior of the duct so that the cables tend to overheat and increase their electrical resistance, so that scorching or smouldering of the cables can occur.

The invention provides a cableway or duct for electric cables which is at least in part of doublewalled construction having offset ventilation openings in its inner and outer walls, the outer and/or inner walls being coated, at least on their insides with a heat insulating layer forming coating which is activated by heating.

With this construction, ventilation of the interior of the duct is ensured in a simple manner through the ventilation openings in the walls to prevent overheating of the cables. At the same time, because the ventilation openings are offset in the inner and outer walls respectively, flames cannot strike the cables in the event of fire. Instead, the flames activate the heat insulating layer forming coatings to protect the cables from damage by the heat.

Depending on the required intensity of such fire protection for the cables, all the channel walls may be coated on their insides and/or their outsides.

Preferably, the duct comprises a channel of double-walled construction and a covertherefor, and the cover is also provided with a heat insulating layer forming coating on its inside and/or its outside which is activated by heating.

In this way it is ensured that thermally insulating layers of foam complete enclosure of the cables in the event of fire.

The coatings responsive to heating may consist of a two-component epoxide resin, such as is sold, for example, by the Metallgesellschaft AG, Frankfurt/M.

under the trad name "Flamarest" 1600 B. Afew seconds after the action of heat at about 280 to 290"C, this material forms a plastics foam layer composed of an organic polymer having a multiple of the thickness of the original coating and this provides effective heat insulation for the cables, the foam layers themselves also withstanding the heat.

A specific embodiment of the invention will now be described by way of example and not by way of limitation with reference to the accompanying drawings in which: Figure 1 shows a cableway or duct according to the invention in cross-section on the line I-I in Figure 2,and Figure 2 shows a plan view of an end region of the cableway of Figure 1 with the cover shown broken away.

The cableway or duct illustrated in the accompanying drawings,-can be positioned in a conventional manner at its place of use. The cableway comprises a channel designated as a whole by 1, and a cover 2 closing the channel 1. The cover 2 can be a separate component which is clipped onto the channel 1 to close the channel at the top. The channel 1 is of double-walled construction and is made up of an inner U-section 3 and an outer U-section 4 which is at the same distance from the inner U-section 3 on all sides. The inner U-section 3 comprises two opposite longitudinal side walls 5 and a bottom wall 6, while the outer U-section comprises two opposite longitudinal side walls 7 and a bottom wall 8.The inner channel walls 5, 6 and the outer channel walls 7,8 are located on al sides at the same mutual spacing by screw connections 9 carrying distance sleeves 9a disposed between the inner bottom wall 6 and the outer bottom wall 8. The screw bolts of the screw connections 9 extend through separate holes, suitably located, in the inner bottom wall 6 and the outer bottom wall 8 respectively.

Ventilation openings 10 are provided in the inner channel wall 5,6 and the outer channel walls 7, 8.

These holes may be formed by stamping and they may be of circular or elongated or other suitable shape. The ventilation openings 10 in the inner channel walls 5, 6 are offset in relation to the ventilation openings 10 in the outer channel walls 7, 8.

The inner channel walls 5, 6 are provided on their inside 11, and the outer channel walls 7,8 are provided on their inside 12, with an insulation layer forming coatings, for example, a coating of material sold by the firm Metallgesellschaft AG, Frankfurt/M.

under the trademark "Flamarest". This material can be applied by means of a brush our a roller to the inside 11 or 12, or it may be sprayed on. In the same manner, the outsides 13 and 14 of the inner channel walls 5, 6 and the outer channel walls 7,8 and also the inside 15 and the outside 16 of the cover 2 can be coated with the insulation layer forming coating.If the insulation layer forming coating is to be provided on the inner channel walls 5, 6, the outer channel walls 7, 8 and/or the cover 2, both inside and outside, then dip coating is recommended for its application, which can be effected for the inner channel walls 5,6 of the inner U-section 3 and the outer channel walls 7,8 of the outer U-section 4 and possibly for the cover 2, before the cableway is assembled.

The inner channel walls 5,6 of the inner U-section 3 carry distance pieces 17 of refractory material, for example, asbestos, disposed spaced apart in the longitudinal direction of the cableway, and the lower arms 18 of the distance pieces support cables 19 laid in the interior of the inner U-section 3. The distance pieces 17 may, for example, be suitably shaped members. The cables 19 are held by the distance pieces 17 in spaced relation to the side walls 5 and the bottom wall 6 of the inner U-section of the channel 1 over the greater part of their length so that unhindered foaming, particularly of the insulation layer forming coating provided on the inside 11 of the bottom wall 6 of the inner channel wall section 3 can take place in the event of fire. The distance pieces 17 do not, as a whole, impair the thermal insulation of the cables 19 provided by the insulation layer forming coatings in the event of fire because thermal insulation is provided also by the distance pieces which are composed of refractory material.

Because they are of narrow, yoke-shaped form, the distance pieces 17 do not impairthe ventilation of the cableway either.

Claims

1. A cableway or duct for electric cables which is at least in part of double-walled construction having offset ventilation openings in its inner and outer walls, the outer and/or inner walls being coated, at least on their insides with a heat insulating layer forming coating which is activated by heating.

2. A cableway or duct as claimed in claim 1, in which the outer and/or the inner walls are coated on their insides and on their outsides with a heat insulating layer forming coating which is activated by heating.

3. A cableway or duct as claimed in claim 1 or 2 comprising a channel of double-walls construction and a cover therefor, and the cover is also provided with a heat insulating layer forming coating on its inside and/or its outside which is activated by heating.

4. A cableway or duct as claimed in any preceding claim in which the insulating layer forming coating consists of a two-component epoxide resin which forms a thermally insulating foam layer when activated by heating.

5. A cableway or duct as claimed in any preceding claim in which the inner walls carry distance pieces to support the cables clear of the walls at spaced apart locations in the longitudinal direction of the cableway.

6. A cableway or duct as claimed in claimed 5 in which the distance pieces are composed of fireproof, thermally insulating material.

7. A cableway or duct for electric cables substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.