GB2329688A - Weather proofing protection for pipework - Google Patents

Abstract

A weather proofing sheet 1 is wrapped around a pipe 3 so that it overlaps 4 and is bonded to itself, this bonding being the primary means of securing the sheet 1 to the pipe 3. The sheet 1 is preferably non-metallic, and is more preferably formed of a rubber compound such as polychloroprene rubber. Preferably, the overlapping edges are bonded together using an adhesive, and a waterproof sealant is applied externally over the exposed edge of the bonded overlapped edges. The sheet 1 is preferably stretched around the pipe 3 to tighten it against the pipe 3. Additional adjacent sheets 1 may be secured to the pipe 3 (shown in steps 2 and 3), each adjacent sheet also being overlapped 4. The pipe may include a layer of insulation 2 around which the sheet 1 is wrapped, or alternatively the insulation for the pipe 3 may be provided by the weather proofing sheet 1 itself, which is preferably in the form of a laminate of a rubber compound based weatherproof sheeting layer bound to a thermal insulation layer. In addition to being applied to straight pipes as shown, the sheet 1 may also be applied to ends of pipes (figure 2), pipes with reducing diameter (figure 3), bending pipes (figure 4), and T-pieces (figure 5). The sheet 1 may also be easily repaired if required (figure 6).

Description

WEATHER PROOFING PROTECTION OF PIPEWORK Field of the Invention The present invention relates to an improved method and apparatus for weather proofing protection of pipework and is particularly although not necessarily exclusively suitable for use in offshore environments such as oil or gas rigs.

Background to the Invention The environmental conditions to which pipework is exposed on offshore oil and gas rigs are particularly severe. Improved methods of protecting the pipework against corrosion are constantly being sought.

For much of the pipework there is an additional requirement to provide some form of thermal insulation especially to protect against the sub zero temperatures often experienced at sea.

A common general approach to providing the protective cover for the pipework is to apply a sheet of insulating foam around the pipework and to then coat the external surface of the foam with an adhesive to which an outer weather proofing sheet is then applied to enwrap the pipework. Such prior art methods are, however, not entirely reliable and are inherently laborious and costly.

It is, therefore, a general objective of the present invention to provide a relatively swift and efficient system for cladding pipework to provide weather proofing.

Summary of the Invention According to a first aspect of the present invention there is provided a method for protecting pipework which comprises mounting around the pipework a weather proofing sheet, wherein the weather proofing sheet is mounted to the pipework directly ot indirectly as a jacket which is wrapped around the circumference of the pipework and overlapped and bonded to itself as the primary means of securing the weather proofing sheet to the pipework.

The jacket of weather proofing sheet is generally not bonded directly or indirectly to the pipework to any substantial extent other than suitably where the jacket ends along the pipework or where the jacket is perforated by protrusions from the pipework or has inspection "windows" being gaps or removable pieces in the jacket for viewing the pipe surface. At such locations a watertight seal is required between the jacket and the pipework.

Suitably the method comprises the steps of: providing a weather proofing non-metallic sheet material for cladding the pipework; cutting from the sheet material a first piece that is sufficient to wrap around the circumference of a selected length of the pipework completely and provide an overlapping edge; mounting the piece of sheet material around the selected length of pipework and applying adhesive substantially only to one or both of the overlapping edges to bond them together in order to hold the sheet material on the pipework.

Preferably when mounting the piece of sheet material around the pipework the sheeting is stretched around the pipework to tighten it against the pipework. For this reason and also for improved water proofing and fire proofing the sheeting material suitably comprises rubber and preferably polychloroprene rubber.

The method preferably comprises repeating the aforementioned steps of the method to apply respective further pieces of sheeting to each next adjacent length of the pipework and wherein each next adjacent piece of sheeting is mounted with its end edge overlapping with the end edge of the preceding piece of sheeting and with the two pieces bonded together at the overlapping end edges by adhesive applied to one or both of the end edges.

Brief description of the drawings Preferred embodiments of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, wherein: Figure 1 is a diagram illustrating the successive stages of a first preferred embodiment of the method of the present invention for cladding straight lengths of pipe; Figure 2 is a diagram illustrating successive stages of cladding the pipe at a flange termination; Figure 3 is a diagram illustrating successive stages of cladding of a pipe reducer section of pipework; Figure 4 is a diagram illustrating cladding of a pipe bend; Figure 5 is a diagram illustrating cladding of a tee section; and Figure 6 is a diagram illustrating a simple technique for repairing minor external damage to the cladding.

Description of the Preferred Embodiments Referring to Figure 1, this illustrates applying short lengths of weather proofing sheet 1 around a pipe 3 that is already lagged with a layer of insulating material 2.

The short length of weather proofing sheeting 1 is suitably an elastomeric material. A particularly preferred example is a fire retardent rubber compound such as polychloroprene rubber which may be modified with mineral fillers, processing oils and vulcanising agents. It is suitably formulated with inorganic additives to enhance its fire retardent properties and long term durability.

Suitably the weather proofing sheeting is supplied in roll form and may have a roll width of, for example, 500 mm and length of 20 m or more. In the procedure illustrated in Figure 1 this 500 mm roll width defines the length of each portion of pipe 3 that is clad at each stage.

In the first step of the procedure, step 1, the layer of insulation around the pipe 3 is checked to ensure that it is clean, dry and free of dust, foreign matter and other contaminants. The circumference of the pipe 3 including the insulating layer 2 is established. Allowance is then made for an extra 40 mm for end overlap and then the required portion of weather proofing sheeting 1 is cut from the roll of sheeting. The dimension of sheeting to be cut can simply be marked on the preferred polychloroprenebased sheeting by either a pencil or tailor's chalk.

Initially the portion of weather proofing sheeting 1 is fitted around the pipe 3 on a trial basis prior to application of contact adhesive to the overlapping joint 4. During the trial fit all penetrations must be marked and a corresponding cut made in the weather proofing sheeting 1 at the correct position.

Having completed the trial fit, the weather proofing sheeting 1 must be checked to ensure that it is clean, dry and free from dust, foreign matter and other contaminants prior to applying contact adhesive to the mating surfaces of the overlapping joint edges 4.

The adhesive may suitably be applied by a short stiff bristled brush as a thin uniform film. An example of suitable adhesive is a well known brand marketed as Armstrong 520 contact adhesive supplied by Armstrong World Industries Ltd of Oldham, Lancs. Adhesive of this type generally requires between two to eight minutes for the adhesive to "tack dry" before making contact with the mating surface.

Following application of the adhesive to the weather proofing sheeting portion 1 at the selected overlapping joint areas 4 and once the adhesive has tack dried, the weather proofing sheeting 1 may then be applied over the insulating layer 2.

While wrapping the weather proofing sheeting 1 around the pipe 3, a constant pressure should be applied, pulling the edges 4 to be overlapped together but with care being taken not to over-tighten the weather proofing sheeting 1 around the insulation 2.

A final check for fit and alignment should be made prior to making contact between the overlapping joint edges 4 and the joint 4 may then be closed tight by applying even, firm pressure to the overlap to ensure that a good tight bond is achieved.

Once the joint is made and ensuring that the outer surface of the joint is clean, dry and free from dust, foreign matter and other contaminants, a sealant adhesive is suitably applied to the outer surface of the joint. One sealant adhesive that is

recommended for the purpose is widely available and marketed as Simson,tSR 70 -03 manufactured by Simson BV of 'S - Hertogenbosch, Netherlands.

The sealant adhesive is suitably applied from a traditional cartridge tube using a traditional applicator pump gun.

The bead thickness of the sealant should preferably be about 8 mm wide and 3 mm high with the edge of the overlap in the centre of the bead to ensure a completely water tight seal is achieved.

In the next step 2, of the illustrated steps in Figure 1 a next consecutive length of the insulated pipe 3 is clad with a piece 1' of the weatherproof sheeting 1.

In step 2 of the illustrated method, the next adjacent length 1', of weather proof sheeting 1 is wrapped around the insulated pipe not simply butting against the existing length of weather proof sheeting 1 but overlapping it suitably again by a distance of approximately 40 mm.

In the third illustrated step of the procedure a third length of weather proof sheeting 1" is mounted to the insulated pipe again slightly overlapping the preceding length of weather proof sheeting 1' The procedure is repeated again and again until the entirety of the pipe 3 is clad and the ends of the insulation 2 on the pipework 3 are then sealed off.

An example sealing technique is illustrated in Figure 2.

In Figure 2, full enclosure by end sealing of the sleeve formed by the weather proofing sheet 3 is achieved by wrapping a relatively short length 10 of the weather proofing sheet 1 around and over the end of the insulating layer 2 to encase the end of the insulating layer 2. This overlaps the adjacent end of the last portion 1" of weather proofing sheet wrapped around the insulated pipe 3 and is sealed in place with sealant at the overlapping edges and around the pipe 3.

Referring to Figure 3, this shows a suitable sequence of stages for applying a weather proofing sheeting 1 around an insulated pipe 3 at a shoulder of the pipe 3 where the pipe reduces in diameter.

Figure 4 illustrates cladding of an insulated pipe 3 with the weather proofing sheeting 1 at a bend of the pipe 3. Here the weather proofing sheeting may be overlapped unevenly, in a so-called lobster-backed" or "spiral wrapped" fashion. The contact adhesive is applied to the lap joints in the same manner as for the straight length of pipework 3. The resilient stretching of the weather proofing sheeting 1 will ensure a tight seam. As with the straight lengths of pipework 3, all overlapping joints should ideally be downward facing to form a watershed seal. Furthermore, during or after the covering procedure all joints/laps should be sealed with the recommended sealant and adhesive.

Where appropriate, the sheeting 1 may be cut to shape to better suit a varying pipe profile.

In Figure 5, where the weather proof sheeting is used to clad a tee section, the overlap at the interface of the two pipes 3 may be cut or stretched to suit the enlarged circumference at the interface.

Finally, Figure 6 illustrates a simple technique for repair of a damaged section of the weather proof sheeting 1 of the cladding by adhering a panel over the torn part of the weather proof sheeting 1 and overlapping to a sufficient extent to be securely sealed in place by the adhesive and sealant. As previously, the preferred overlap is of the order of 40 mm.

Although in all of the above described method steps the method is described for mounting the weather proof sheeting as a jacket (closed sleeve) around the insulation layer of insulated pipework, the method may also be used to apply a composite weather proof sheeting layer to pipework, where the weather proof sheeting is combined with insulating material. This is most simply formed by laminating a weatherproof sheeting layer to an insulation layer, the two being bonded by suitable adhesive.

Even in composite form, the weather proofing and insulation sheet may be easily applied following the same procedure as described above for the first embodiment of the invention. The composite retains its elasticity and may be stretched to provide a tight fit around the pipe.

By using such a composite system even greater savings may be had in installation time.

In contrast to existing systems for pipework protection , the systems of the present invention are extremely simple and swift for installation of the cladding with no special tools or skills required and very substantial commensurate savings in cost.

Furthermore, with low installation times there is less risk of delays and poor finish quality due to adverse changes in weather conditions during installation and initial trials of the systems have shown that they are extremely efficient and effective.

Claims (12)

1. A method for protecting pipework which comprises mounting around the pipework a weather proofing sheet, wherein the weather proofing sheet is mounted to the pipework directly or indirectly as a jacket which is wrapped around the circumference of the pipework and overlapped and bonded to itself as the primary means of securing the weather proofing sheet to the pipework.

2. A method as claimed in claim 1, wherein the method comprises the steps of: providing a weather proofing non-metallic sheet material for cladding the pi pework; cutting from the sheet material a first piece that is sufficient to wrap around the circumference of a selected length of the pipework completely and provide an overlapping edge; mounting the piece of sheet material around the selected length of pipework and applying adhesive substantially only to one or both of the overlapping edges to bond them together to hold the sheet material on the pipework.

3. A method as claimed in claim 1, 2 or 3 wherein when mounting the piece of sheet material around the pipework the sheeting is stretched around the pipework to tighten it against the pipework.

4. A method as claimed in claim 1, 2 or 3 wherein the sheeting material comprises a rubber compound and preferably polychloroprene rubber.

5. A method as claimed in any preceding claim, wherein the method comprises repeating the steps of providing weather proofing sheet material and mounting it to the pipework to apply respective further pieces of sheeting to each next adjacent length of the pipework and wherein each next adjacent piece of sheeting is mounted with its end edge overlapping with the end edge of the preceding piece of sheeting and with the two pieces bonded together at the overlapping end edges by adhesive applied to one or both of the end edges.

6. A method as claimed in any preceding claim, wherein the overlap is between 20 mm and 60 mm and preferably of the order of 40 mm.

7. A method as claimed in any preceding claim, wherein a waterproof sealant is applied externally over the exposed edge of the bonded overlapped edges.

8. A method as claimed in any preceding claim, wherein the weather proofing sheet is mounted over an external insulation layer of pipework that is already clad with an insulation layer.

9. A method as claimed in any of claims 1 to 7, wherein the waterproof sheeting is mounted over pipework that has no insulation layer and the waterproof sheeting is a composite incorporating such thermal insulation.

10. A method as claimed in claim 9, wherein the composite is a laminate of a rubber compound-based waterproof sheeting layer bound to a thermal insulation layer.

11. A weather proofed pipework installation which has been weather proofed by the method of any preceding claim.

12. A method as hereinbefore described with reference to any suitable combination of the accompanying drawings.