FULL ENCIRCLEMENT STEEL SLEEVE

Full-encirclement steel sleeves have historically been a widely used method for general repair of defects in onshore pipelines. The results of this work showed that a properly fabricated steel sleeve restores the strength of a defective piece of pipe to at least 100% of SMYS. The keys to properly fabricating a sleeve are the use of some proven procedure and skilled personnel. Steel sleeves are used to repair defects such as :

·       Leaks 

·       Dents

·       Gouges

·       Cracks;

·       Metal loss

·       Other anomalies such as coating damages, buckle etc limited to the sleeve specification

The repair system consists of seam welding two half-section pipes with an inner diameter equal to the outer diameter of the pipe around the damaged section. There are two types of steel sleeves used for pipeline repair. Type A sleeves which are only seam welded without welding the ends to the carrier pipe, and Type B which are welded at the ends contributing to a fully pressure containment around the damage. In addition, a semi-liquid material can be used to fill and harden in any gaps in the annular space between the sleeve and the carrier pipe.

The use of full encirclement steel sleeves for pipeline repair was developed during work lead by Kiefner at Battelle in the early 1970s. Prior to this, repair by cutting out and replacing the damaged segment was common. There are two basic types of full-encirclement steel sleeve .

Type A sleeves encircle the pipeline and provide structural reinforcement of the defective area. To do this, they do not require sleeve-end fillet welds. Type B sleeves also encircle the pipeline and provide structural reinforcement, but since the ends are fillet welded to the pipeline, they can also contain pressure in the event that the defect is leaking or will eventually leak in subsequent service. According to Fawley and Stephens et al. the use of fibre-reinforced composite materials for pipeline repairs was developed during work at Southwest Research Institute and Battelle in the late 1980s. There are two basic types of composite repair systems; pre-formed (composite sleeves)  and wet lay-up (composite wraps).

The use of wet lay-up systems for pipeline repair began in the early 1990s. These wet lay-up systems use either a resin-impregnated cloth that is activated by water in the field or a cloth that is saturated with epoxy resin in the field .

Type A & B sleeve was simply used to connect a pipeline instead of a circular weld. Since a type B-sleeve may have a significant pressure and/or longitudinal stress exerted by lateral loads on the tube, it should be designed to bear the maximum pressure of the carrier pipe. It should also be manufactured and tested carefully in order to ensure its quality.

Names: Full Circle Sleeve, Full Cleaning Sleeve, type A Sleeve, type B Sleeve, Half Pipe Sole, Split Sleeve, Half Pipe Cap, etc.

As a world-renowned Pipline Repair Exporter Sleeve, Half Repair Sleeve is dedicated to providing highest levels of customer satisfaction to every customer. We sell a wide range of Half Pipe Sole items in the full circle sleeve in India and Overseas like Singapore, Thailand & Indonesia.

The mechanism by which composite materials reinforce areas of damage on operating pipelines is much more complex. While the strength of composite materials is similar to that of line pipe steel, the elastic modulus is significantly lower. For a composite material to prevent a defect from rupturing, the defect must typically plastically deform in the process of the load being transferred to the composite. Brittle pipe material or seams may only be able to tolerate a very small amount of plastic strain before a defect in the pipe or seam grows and fails.

For both steel sleeves and composite repairs, a high-compressive strength filler material is used to fill defect areas so that load is effectively transferred to the repair material.

With very few exceptions, the applicability of Type A sleeves and composite repairs are similar. The two exceptions are repair of arc burns, where Type A sleeves can be used without complete removal of metallurgically altered material whereas composite repairs cannot, and repair of hydrogen-induced cracking (HIC) and blistering, where Type A sleeves can be used and composite repairs cannot. Both of these exceptions are the result of composite materials having an elastic modulus that is significantly lower than that of steel. As a result of the lower elastic modulus and the susceptibility of these defects to grow upon the application of comparatively small amounts of strain, the composite repairs allow these defects to strain sufficiently to cause them to fail or grow by fatigue.

On the other hand, Type B sleeves can be used to repair a wide variety of defects for which composite repairs cannot.

Type A sleeves, Type B sleeves and composite repairs are all acceptable for relatively shallow to moderately deep external corrosion (less than 80 per cent deep). Very deep external corrosion (80 per cent deep or greater) should be repaired only using methods that are appropriate for leaks (i.e. Type B sleeves).

Another claimed advantage of composite repairs is that their installation is simpler than steel sleeves. While this may be the case for Type B sleeves where welding to an in-service pipeline using specially qualified welding procedures and specially qualified welders is required, this is certainly not the case for Type A sleeves. Type A sleeves require no in-service welding, can have fillet-welded overlapping side strips (see Figure 4), and are very simple to fabricate and install. They can be supplied with the side strips fillet welded to the bottom half of the sleeve so that the only welds required in the field are the fillet welds on the top of the side strips. These welds can be readily made by welders without special training or qualification. The raw materials required to make Type A sleeves are significantly less expensive than composite materials. Type A sleeves can be fabricated in the field by simply splitting a length of pipe of equal, diameter, wall thickness and grade as the line-pipe material. Unlike composite materials, steel sleeves have no finite “÷shelf life’. Also, the stiffness and long-term performance of Type A sleeves are equivalent to that of line-pipe steel.

While the long-term performance of steel is well established, the long term performance of composite materials on buried pipelines beyond about 20 to 25years has not yet been demonstrated. The significantly reduced stiffness of composite materials compared to steel makes the use of composite repairs questionable for application to pipelines that experience cyclic pressure fluctuations. Cyclic strains in the defect area may cause the defect to grow and eventually fail in subsequent service.

Both Type A sleeves and composite sleeves rely upon the use of an effective sealer to keep potentially corrosive fluids (e.g. groundwater) from entering the crevice area between the carrier pipe and the repair. Corrosion under Type A sleeves can be prevented by using either an elastomeric sealant or a hardenable sealant.

While Type B sleeves do have to be fillet welded to the pipeline (see Figure5), they can be used where composite repairs cannot, such as for repair of defects that are 80 per cent deep or greater, circumferentially-oriented defects, leaking defects or for defects that will eventually leak (e.g. internal corrosion), and cracks. The raw materials required to make Type B sleeves are significantly less expensive than composite materials and the stiffness and long-term performance of Type B sleeves are equivalent to that of line-pipe steel.

When considering the cost of various repair options, both material cost and cost of installation need to be considered. Mobilisation cost and the application cost of steel sleeves may be highly variable, depending upon availability and labour rates for welding personnel. While the mobilisation cost for composite repair installation may be less in some cases, the materials are more expensive. Composite sleeves or wet layup composite repair kits are typically designed for a standard, fixed length. If the length of the area requiring repair is longer than that which can be repaired by a single composite sleeve, the use of steel sleeves may be significantly less expensive than composite repairs.

Welds made onto in-service pipelines tend to cool at an accelerated rate as the result of the ability of the flowing contents to remove heat from the pipe wall. Accelerated cooling rates promote the formation of hard weld microstructures that are susceptible to hydrogen cracking (see Figure 7).

Hydrogen cracking requires that three primary, independent conditions be satisfied simultaneously: hydrogen must be present in the weld, there must be a susceptible weld microstructure, and tensile stresses must be acting on the weld.

Simple guidance has been developed and is available elsewhere for preventing both burnthrough and hydrogen cracking when welding onto an in-service pipeline.

The use of full-encirclement steel sleeves for pipeline repair is a relatively mature technology. As a result, relatively little is written about the use of steel sleeves compared to the use of composites where new products are continually introduced.

The applicability of Type A sleeves is nearly identical to that for composite repairs and their installation involves no welding to an in-service pipeline. Type B sleeves can be used where composite repairs cannot, such as for repair of defects that are 80 per cent deep or greater, circumferentially-oriented defects, leaking defects or for defects that will eventually leak (e.g. internal corrosion), and cracks.

For both types of full-encirclement steel sleeve, the raw materials are relatively inexpensive and the stiffness and long-term performance is equivalent to that of line pipe steel.

The installation of Type B sleeves does involve the need to weld to an in-service pipeline. Adherence to the simple guidance summarised here will avoid the potential concerns associated with welding to an in-service pipeline.

There are two types of full wrap encirclement sleeves:

• Type A is longitudinally welded along its connecting edges but not welded to the pipe at the ends.

• Type B is welded on the ends to the carrier pipe in addition to the longitudinal weld. Type B is the recommended installation because it is pressure containing.

Sleeve material is listed in the Pipe Welding procedure (MIP-407) by pipe material/sleeve material classification. See Section 5.9.10 and 5.9.11 for girth weld and long repair lengths. For assistance, contact the Asset Integrity Team (Pipeline Integrity Technologist).

The sleeve material wall thickness must be calculated to accommodate the full design pressure of the mainline pipe on which it is installed. Use the following formula:

T=………..

Where:

T_s= Minimum sleeve thickness in inches (at full design pressure)

T_p= Minimum pipe thickness in inches (at full design pressure)

S_s= SMYS for the sleeve material in psi

S_p= SMYS for the pipe material in psi

D_p= Outside diameter of the pipe in inches

The sleeve thickness must be greater than or equal to the pipe wall thickness. Sleeve material of higher SMYS than the pipeline shall have a wall thickness equal to or greater than the original pipeline design thickness. No credit shall be taken for the increased SMYS of the sleeve. If the sleeve thickness is greater than

the pipe thickness, the ends of the sleeve must be chamfered at a 45 degree angle to a thickness equal to the pipe.

Inspect the wall thickness.

The integrity of the pipe at the fillet weld location must be verified. This may be done using an ultrasonic thickness gage and by visual inspection.

The minimum pipe wall thickness at the location where the sleeve will be welded to the pipe is .188 inches.

Prepare the pipe as described in section 5.6 of this procedure.

Prepare the sleeve and fit it to the pipe.

Wire brush the internal surface of the sleeve to remove dirt, rust, scale, and other foreign materials.

A factory manufactured half sleeve is usually ten feet long and may be cut to the required length in the field. The minimum length for a sleeve is four inches per DOT.

A backing strip is recommended at the longitudinal butt weld to protect the pipe from weld damage. The strip must be a minimum of 16 gauge (.0625 inch thick) mild carbon steel cut to the length of the half sleeve. Tack weld the strips to the bottom half of each side, with welds approximately a half inch long and spaced twenty-four inches apart. Follow the sleeve manufacturer’s instructions, if available.

When sleeves are used to repair dents, fill the dent with a hardening filler material such as epoxy or automobile body putty before installing the sleeve.

Place the bottom sleeve, with the backing strips attached, under the pipe with the edges of the strip barely touching the sides of the pipe. Position the top sleeve over the pipe using wedges on the ends of the top sleeve’s longitudinal seam to provide clearance for the backing strip to fit underneath the top half.

Plate clamps can be used for positioning the top sleeve and can be removed when the proper position is obtained. Spreader bar rigging may be used when handling long half sole sleeve sections.

Once the half sole sleeves are in close proximity to the pipe, position the chain clamps around the half sole. Chain clamps should be fabricated of a diamond, double roller type chain. The tightening mechanism must be supported by a metal shoe contoured to the shape of the half sole/pipe.

Tighten the clamps at an equal rate on each clamp until the top half sole has cleared the backing strips. At this point, the wedges can be removed. Continue tightening the clamps until the half sole is firmly in position.

Remove any hydrocarbon film on the sleeve and pipe at the fillet weld location with a suitable solvent. This is an important step and integral to ensuring a low-hydrogen weld!

Reduce the pressure by one third of the normal operating pressure to allow the sleeve to share hoop stress. In cases where the product or operation does not allow the pressure to be dropped by one third, consult the Asset Integrity Team (Pipeline Integrity Technologist) or Technical Services before continuing.

After the pressure is reduced, complete final tightening of the sleeves.

The gap of the longitudinal weld groove is critical. The gap must be 1/16 inch on each side. Reposition the sleeve or grind the edges to achieve the proper gap.

Weld the sleeve per the Pipe Welding procedure (MIP-407).

The sleeve installation welding procedure is a low hydrogen API-1107 process. Use absolutely dry low hydrogen electrodes and carefully control the size and shape of the circumferential fillet weld. The leg of the fillet weld should equal 1.4 times the wall thickness of the pipe. Strive for a concave faced fillet weld, with streamlined blending into both members; avoid notches and undercuts. The smoother and more streamlined the weld, the greater the resistance to fatigue. The longitudinal welds must be completed before welding circumferentially type “B” full encirclement sleeves.

If the area to be sleeved contains a girth weld that may provide difficulty with fitting a plain sleeve, an expanded sleeve (sometimes called a pumpkin) can be installed providing the material meets the requirements listed in MIP-407.

If the area to be sleeved is longer than the sleeve material and additional pieces must be used, use one of the following methods:

• Butt weld the sleeves together at each end and radiographically inspect the butt welds prior to installing the sleeve halves on the pipeline.

• Leave a minimum of ½ pipe diameters (or 4” minimum) between the two sleeves.

• Butt the sleeves together and install another sleeve over those using the proper sleeve weld procedure listed in MIP-407. The overlapping sleeve must be at least 12” long and centered over the primary sleeve ends. The overlapping sleeve must be oversized (larger inside diameter) and be able to cover the entire circumference of the primary sleeve. The overlapping sleeve material and thickness must be calculated using the larger outside diameter of the primary sleeves.

They can be used for internal and external leaks,corrosion,grooves, gouges, dents, arc burns, laminations, defective girth welds and cracks. Pressure containing sleeves feature a wall thickness equal to or greater than required for the maximum allowable operating pressure or the full strength of the pipe being repaired.

1.0035             S185	1.0038(dubl)             S235JR
1.0044             S275JR	1.0045             S355JR
1.0050             E295	1.0060             E335
1.0070             E360	1.0114             S235J0
1.0116(dubl)             S235J2(+N)	1.0117             S235J2
1.0143             S275J0	1.0144             S275J2(+N)
1.0145             S275J2	1.0553             S355J0
1.0570(dubl)             S355J2(+N)	1.0577             S355J2
1.0590             S450J0	1.0595             S355K2(+N)
1.0596             S355K2

EN 10025-3: 2004 Hot rolled products of structural steels. Technical delivery conditions for normalized/normalized rolled weldable fine grain structural steels COMPARE GRADES

1.0490             S275N	1.0491             S275NL
1.0545             S355N	1.0546             S355NL
1.8901             S460N	1.8902             S420N
1.8903             S460NL	1.8912             S420NL

EN 10025-4: 2004 Hot rolled products of structural steels. Technical delivery conditions for thermomechanical rolled weldable fine grain structural steels COMPARE GRADES

1.8818             S275M	1.8819             S275ML
1.8823             S355M	1.8825             S420M
1.8827             S460M	1.8834             S355ML
1.8836             S420ML	1.8838             S460ML

EN 10025-5: 2004 Hot rolled products of structual steels. Technical delivery conditions for structural steels with improved atmospheric corrosion resistance COMPARE GRADES

1.8945             S355J0WP	1.8946             S355J2WP
1.8958             S235J0W	1.8959             S355J0W
1.8961             S235J2W	1.8963             S355J2W(+N)
1.8965             S355J2W	1.8966             S355K2W(+N)
1.8967             S355K2W

Inspection of Full Encirclement Steel Sleeves
Every single pipe sleeve is accurately examined and inspected for defects before delivery. The shipment is thoroughly tested and verified for durability and stability.
Our quality experts first review the entire shipment of Full encirclement Steel Sleeves before we dispatch them to our clients. Parts that do not meet our strict standards are rejected immediately and not shipped.

Our export account is now available in different countries such as the United States, Africa, Singapore, Australia, the United Arab States, the Russian Union, Saudi Arabia, Kuwait, Iraq, Yemen, Qatar, Malaysia, Indonesia, Vietnam, Korea, South Africa, Libyan, Liberia, Kenya, Thailand and more. Then we have an export account in Southern Africa.