GB2043813A

GB2043813A - Fire Resistant Pipe Joints

Info

Publication number: GB2043813A
Application number: GB7907686A
Authority: GB
Original assignee: Beaveridge A G
Current assignee: Beaveridge A G
Priority date: 1979-03-05
Filing date: 1979-03-05
Publication date: 1980-10-08

Abstract

A (steel) clamping ring 20 is provided for a flanged 12, 13 pipe joint 10, 11 or coupling, the ring 20 having a layer or coating 21 of an intumescent substance on its inner surface. The intumescent annular ring 21 locates in a gap 17 between the flanges 12, 13. This gap 17 communicates via a chamber 16 with a gasket 19. In the event of fire the layer 21 swells and substantially closes the gap 17 between the flanges 12, 13 restricting leaks and protecting the gasket 19. Ring 20 is formed as a band clip whose ends are bolted. <IMAGE>

Description

SPECIFICATION A Clamp Ring for Increasing Fire Resistance in Pipework Joints This invention relates to a clamp ring for increasing the fire resistance of pipework joints and couplings, particularly flanged joints and couplings.

Pipeworkjoints and couplings, and particularly flanged connections are the points which offer lowest resistance to external fire.

An object of the invention is to provide a selfcontained device which can be fitted to existing pipework joints and couplings and which will increase the fire resistance of the joint or coupling.

According to the invention, there is a clamp ring for application to the exterior of a pipework joint or coupling, the clamp ring having on its inner surface an annular layer or coating of an intumescent material.

An intumescent material is one which swells upon change in environmental conditions. We are especially concerned with heat sensitive intumescent material, which, when the ambient temperature increases, undergoes a chemical change and expands, thus creating a heat barrier.

Preferably, the intumescent material is a heat sensitive material. Preferably, the clamp ring itself is made of light gauge steel, e.g. 18 or 20 gauge steel.

Preferably, the ring has a simple locking device which may be, for example, in the form of a simple bolt fastening.

Preferably, the ring has a small hole or holes which acts as a weep hole(s) to show the existence of a leak.

The intumescent material may be arranged around the hole or holes to close it (them) in the event of a rise in temperature due to a fire.

From another aspect, the invention relates to a flanged connection for pipework, the connection including a sealing gasket between the flanges, and a clamp ring located around the join between the flanges, the clamp ring having on at least part of its inner face a layer or coating of intumescent material. In one construction, there may be a gap between the radially outer ends of the flanges, the gap being in communication with the gasket and being closed or partially closed by an annulus of intumescent material so arranged that said material will, on heating, swell and close the gap to create a heat barrier and protect the gasket, the annulus of intumescent material being held in place by the clamping ring.

The gasket may be a separate item or it may be an extension of a plastic lining of the pipework.

In the accompanying drawings:~ Figure 1 is a section through a flanged pipe joint embodying a clamp ring according to the invention; Figure 2 is a section through the clamp ring at its lowermost point, as seen in Figure 1; Figure 3 is a plan view of the portion of the clamp ring shown in Figure 2; Figure 4 is a section through a portion of the clamp ring showing one form of locking means, and Figure 5 is a view similar to Figure 1 of an alternative construction.

In Figure 1 is shown a flanged pipe joint joining two portions of pipe 10, 11. Each pipe portion has a flange 12, 13. The outer portions 14, 15 of the flanges 12 and 13 are of reduced thickness and define a chamber 16 thus creating a gap 17 between the flanges. The flanges are bolted together by a number of bolts 18 (only one being shown) spaced around the flanges.

A sealing gasket 19 is trapped between the flanges 12 and 13. This gasket may be discrete part as shown in this embodiment or it may be an extension of a plastic lining for the pipe.

The joint has a clamp ring 20 of light gauge steel applied to its outer periphery and the ring 20 has attached to it an annular ring 21 of a heat sensitive intumescent material such as that marketed by Schlegel (UK) Engineering Ltd. This would be of the order of 1/1 6th to 1/8th inch thick.

The intumescent ring 21 does not quite bridge the gap 17. A weep hole 23 is shown formed in a lower portion 22 (Figure 2) of ring 20 and the intumescent material has a small hole 24 communicating with hole 23. It will be appreciated that one or more further such holes may be provided around the clamp ring.

The ring can be clamped in place by a simple locking device, e.g. a nut and bolt arrangement, as illustrated at 25 in Figure 4.

If a leak develops in the pipe joint fluid will initially escape through the weep hole(s) 23.

If there is a fire or undue heat adjacent the pipe joint, the intumescent ring 21 will heat up, a chemical change will take place and the ring will swell to fill and seal or partially seal the gap 17 and also to close or partially close the weep hole(s) 23. This immediately creates a heat barrier which protects the gasket from the fire.

Furthermore, the pipe joint may be sealed off or at least partially sealed and further escape of fluid will be prevented or at least reduced. If the fluid is an inflammable gas or liquid this will at least reduce the chance of the fire being spread by leaking gas or liquid.

In the alternative construction of flanged pipe connection shown in Figure 5, parts similar to those of the previous construction bear the same reference numerals. In this construction, however, each pipe 10, 11 has a flat faced flange 120,130, between which a gasket 190 is located. The gasket is shown extending radially throughout the total depth of the flanges, but this is not essential.

In order to protect the joint, and especially the gasket 190 in the case of fire, a clamp ring 20 is again provided to surround the joint, the clamp ring being held in position in known manner, and having a layer or coating of intumescent material 210 on its inner face. As shown, this layer 210 extends over the entire inner face, but this is not essential. In other respects the clamp ring may be similar to that of Figures 1-4.

Thus a device according to this invention meets the following requirements when used on a flanged connection of a pipeline (which is the point on a pipeline offering least resistance to an external fire).~ 1) It increases the fire resistance of the flange joint from an external heat source.

2) When the pipe contains liquid, any leaks (or seepage) at the flange joint can be easily seen.

3) Upon the application of external heat, any leak at a flange joint will be throttled down, thus restricting the amount of leaked substance which will feed the fire.

4) The device can be fitted to an existing pipework system without the flanges being dismantled.

5) The device is self contained, and does not require cleats or fixings of any kind to be attached to the flanges or pipework.

Claims

1. A clamp ring for application to the exterior of a pipework joint or coupling, the clamp ring having on its inner surface an annular layer or coating of an intumescent material.

2. A clamp ring according to claim 1 and in which the intumescent material is heat sensitive.

3. A clamp ring according to claim 1 or 2 which has at least one small "weep" hole therein, the or each hole also passing through the intumescent layer or coating but being small enough in relation to the thickness of the intumescent layer to ensure that it will be closed or partially closed when the intumescent layer is caused to expand by increase of surrounding temperature.

4. A clamp ring according to any of clams 1-3 including a locking device for retaining the ring on the joint or coupling.

5. A clamp ring according to any of claims 14 and in which the ring is made of light gauge steel.

6. A flanged pipe joint or coupling incorporating a clamp ring according to any of claims 1-5.

7. A flanged pipe joint according to claim 6 and in which the ring is arranged to cover a gap between the radially outer ends of annular flanges of a pipe joint, the gap communicating directly, or via an internal chamber formed between the flanges, with the gasket between the adjacent flanges and the intumescent material filling or substantially filling said gap.

8. A clamping ring for a pipework joint or coupling substantially as hereinbefore particularly described and as illustrated in the accompanying drawings.

9. A flanged pipework joint incorporating a clamping ring substantially as hereinbefore particularly described and as illustrated in the accompanying drawings.