GB2299845A

GB2299845A - Jacket construction

Info

Publication number: GB2299845A
Application number: GB9507705A
Authority: GB
Inventors: Vincent William Spano
Original assignee: AIC ISO Covers Ltd
Current assignee: AIC ISO Covers Ltd
Priority date: 1995-04-13
Filing date: 1995-04-13
Publication date: 1996-10-16
Also published as: GB9507705D0

Abstract

The jacket, particularly to provide fire protection to a control valve on oil rigs, comprises a stack of laminae each lamina being individually cut to conform closely to the shape of the apparatus in the location where that lamina is to fit, the laminae being arranged in stacks assembled together to form blocks, and pair of blocks fitting around the valve. The blocks are then encased in a wound bandage of a fire protective material, comprising a rubber formulation including a curing retardant.

Description

JACKET CONSTRUCTION This invention relates to a jacket construction to provide fire resistance particularly against hydro-carbon fires.

The problem is to provide such fire resistance for complex shapes of apparatus for example control valves in pipelines on oil rigs.

According to the invention a jacket construction comprises at least two parts which are assembled together to enclose the apparatus between, the assembly having a simple regular external shape, and each half comprising a stack of laminae individually cut to conform closely to the shape of the apparatus in the location where that lamina is to fit, each block being rendered unitary by applied layer and the blocks being wrapped by an outer layer adhered in position.

Preferably the laminae are cut from a so called ceramic log which is a block of felted ceramic fibers laid to form a thickbsheet, for example having a thickness up to say 15 centimeters. The sheet may be cut to provide a series of laminae which have semi-circular external shape and with an internal shape varied according to the profile of the apparatus or like which is to be encased at the particular point where the individual lamina is to fit.

The laminae may be assembled together to form the two blocks either with individual lamina abutted face to face or possibly with them felted together by a needling technique or adhered together with a bonding material or adhesive.

Each block is then encased over the (for example) semi-circular face with an applied layer of plaster which may be brushed or sprayed for example. The plaster may be reinforced by glass cloth or other reinforcing cloth applied between successive coats. The plaster may be resistant to high temperatures.

In order to protect the plaster, which when dry and set may be brittle, a layer of padding is applied for example in the form of a ceramic blanket of possibly 25mm thickness encasing the semi-circular face.

Two such blocks are prepared and are assembled together about the valve or other apparatus which is to be protected, and the blocks may be retained in position and in assembly by strapping of any suitable kind.

An outer layer is then applied for example by winding a suitable cloth to provide a number of layers, the winding being accomplished under tension and the layers being adhered together.

Preferably, the cloth used for the winding is to provide fire protection and consists of a glass cloth with an elastic polymer preferably silicon rubber applied to both sides, one side (conveniently called the outer side) being cured and the other side being uncured. The uncured side is tacky and provides the necessary adhesive and when cured after winding holds the assembly firmly together.

It is preferred to include a suitable pressure sensitive adhesive in the rubber formulation so as to aid the tackiness.

According to an important feature of the invention, a retardant is included in the uncured rubber formulation which may be benzyl peroxide. With an appropriate silicon rubber, the shelf life before curing at normal room temperature may be of the order of say three days, but with the benzyl peroxide added this can be delayed for as long as several months, possibly eight months.

This is particularly convenient in manufacture especially if fire resistant jackets are manufactured at one location in one country and then shipped perhaps to the other side of the world to be installed on an oil rig, since the final winding can only be applied in that installation.

When using the retardant, and completing the assembly, the benzyl peroxide can be burnt off by applying heat locally. The minimum temperature for this purpose is of the order of 850 centigrade, and after that the rubber may be allowed to cure naturally. However, by raising the temperature further for example to 1350 centigrade for a few minutes the effect is also to complete the curing of the rubber.

The jacket construction as thus far described is suitable for protection against hydro-carbon fires. To provide protection against jet fires, an additional layer or layers of the material described in International Patent Application No. PCT/GB94/00304 may be used.

It is preferred to seal the individual blocks against one and another for example by providing a cord of in tumescent material extending along and dropped between the faces which abut one and another when the blocks are assembled together.

The accompanying drawing illustrates 9 stages in the formation of a typical jacket.

Claims

1. A jacket construction comprising at least two parts which are assembled together to enclose the apparatus therebetween, the assembly having a simple regular external shape, and each part comprising a stack of laminae individually cut to conform closely to the shape of the apparatus in the location where that lamina is to fit, each part being rendered unitary by an applied layer and the assembly being wrapped by an outer layer adhered in position.

2. A jacket as claimed in Claim 1 wherein the laminae are cut from a block of felted ceramic fibers laid to form a thick sheet and cut to provide a series of laminae having an internal shape varied according to the profile of the apparatus or like which is to be encased at the particular point where the individual laminae is to fit.

3. A jacket as claimed in Claim 1 or Claim 2 wherein the laminae are assembled together to form the two parts with individual laminae in each part abutted face to face.

4. .N jacket as claimed in Claim 3 wherein the two parts are felted together.

5. A jacket as claimed in Claim 3 wherein the individual laminae are adhered together with a bonding material or adhesive.

6. A jacket as claimed in any of Claims 1 to 5 wherein the assembled parts are encased and reinforced.

7. X jacket as claimed in any preceding claim wherein assembled parts are assembled about the valve or other apparatus and retained in position by strapping.

8. A jacket as claimed in Claim 7 wherein the assembly is provided with an outer layer wound about the assembly.

9. A accet as claimed in Claim 3 wherein the winding cloth is adapted to provide fire protection.

10. A jacket as claimed in Claim 9 wherein the winding cloth comprises a rubber formulation including a retardant.

11. A jacket as claimed in any preceding claim including a cord of intumescent material.

12. A method of making a jacket substantially as described with reference to the accompanying drawings.