Why Choose Heat Shrink Sleeves?

 Why Choose Heat‑Shrink Sleeves for External Pipeline Coating?

Heat‑shrinkable sleeves provide specialized protection for pipeline weld joints, which are areas where the factory-applied coating has been removed for welding and is therefore vulnerable. These sleeves are designed specifically for field joints and are applied directly over the cutback areas of steel pipe. During installation, the heat-activated adhesive softens and forms a strong chemical bond with both the bare steel of the pipe and the factory coating. Once installed and cooled, the polyolefin backing layer hardens into a durable shell that protects the joint from soil pressure, mechanical abrasion, and other stresses that arise once the pipeline is buried.

One of the main advantages of heat-shrink sleeves is their advanced material composition and versatility. The cross-linked polyolefin backing delivers exceptional tensile strength and flexibility, while also offering low moisture absorption and excellent resistance to low-temperature brittleness. These properties result in a high-performance coating with tensile strengths of 30 MPa or more, elongation beyond 550%, and water absorption under 0.1%. Adhesive systems can also be tailored to different applications, with softer mastic adhesives suited for ambient conditions and smaller diameter pipelines, while stronger, semi‑crystalline hot-melt adhesives are chosen for high-temperature and large-diameter applications. This range of options ensures the right balance between flexibility and shear resistance in any operating environment.

Installation in the field is straightforward and efficient, requiring only a propane torch and a roller—there is no need for induction heaters, spray systems, or refrigerated storage. Sleeves are typically supplied in roll stock, allowing crews to cut them to the exact length required for each joint. This minimizes waste and enhances flexibility on site. The simplicity of the process means that crews can complete installation quickly and consistently, even in remote or logistically challenging locations.

Heat-shrink sleeves are also highly compatible with other coating systems. Many configurations include an optional epoxy primer that is applied before the sleeve itself, creating a strong interface between the steel pipe and the adhesive layer. These primers are typically 150 to 300 microns thick and function similarly to fusion bonded epoxy (FBE) coatings. As a result, the sleeve system works harmoniously with the factory coating, bridging the gap in corrosion protection at the joint.

Importantly, heat-shrink sleeves are designed and manufactured to meet major international standards. They comply with ISO 21809‑3, EN 12068, DIN 30672, NACE SP 303, DVGW, and Shell DEP specifications, offering peace of mind regarding quality and global acceptance.

When properly installed, heat‑shrink sleeves form a seamless seal over the weld zone, offering long-lasting protection against corrosion mechanisms such as moisture ingress, galvanic reactions, and contamination from backfill. The mechanical strength of the sleeve resists shear and axial forces that may arise from pipe movement, settlement, or temperature cycling, preserving the integrity of the pipeline system.

Unlike other field-coating options such as tape wraps or liquid coatings, heat‑shrink sleeves deliver a uniform, engineered fit. They avoid the wrinkles, bubbles, and inconsistencies common in tape applications and eliminate the need for expensive application equipment like induction heaters or plural-component spray systems. In addition, they perform well in challenging environmental conditions, benefiting from the strength and resilience of cross-linked polyolefin backing material.

In conclusion, heat‑shrink sleeves offer a highly effective and practical solution for external pipeline coating at field joints. Their robust adhesive bond, mechanical durability, easy installation, and broad compatibility with industry standards make them a trusted choice across the oil, gas, and water pipeline industries. Whether the job calls for small‑diameter sleeves in mild climates or heavy‑duty protection for high‑temperature lines, heat‑shrinkable sleeves deliver the long-term corrosion resistance and physical integrity required to keep pipelines operating safely for decades.

Using Shrink Sleeve Rolls or Cut Pieces

Shrink Sleeves:  Cut Pieces vs Bulk Rolls

     When estimating costs for shrink sleeves, there is one important decision to make.  Shrink sleeves can be purchased two ways:

1. Buy bulk rolls of material (100 to 300 feet long); buy separate closure strips (WPCPIV) and a crew could cut sleeves down from the roll as needed either in the shop or in the field.
2. Buy pre-cut shrink sleeves; which are designed for specific pipe sizes and have the closure pre-attached in the plant.  

     Which is the best solution for you?  Read below and find out.

Here you see a roll of WPCT shrink sleeves with some closure strips (loose).

     Let me be right up front:  this is not what I recommend you do.  Yes, buying rolls of material and loose closures strips (1 per shrink sleeve you intend to cut from the rolls) has some slight appeal.  The material costs can appear to offer some advantages and most pipeline crews have plenty of labor around to cut their own sleeves.  

     There are a lot more potential problems with this route, however:

• A shrink sleeve has an intended cut length.  That cut length is designed to create a sleeve that is long enough to wrap all the way around the field joint and overlap back onto the sleeve.  I've seen too many times when someone in the field uses cut lengths that are simply too short for the sleeve to properly be installed.  That results in a lot of wasted material and labor.
• Installing a "two piece" shrink sleeve (where the WPCPIV closure strip is not plant-attached to the sleeve itself) leads to many more field issues when securing the closure strip than when crews install a once piece pre-cut shrink sleeve.  So many more field issues and questions.
• Cutting shrink sleeves from a roll in the field can be challenging on its own.  You need a long, flat, clean surface to cut on (to avoid getting the sleeve overly dirty on the front end.  In addition, if the sleeve is not cut using the proper equipment; and the sleeve is cut in a way that leaves 'imperfect' or jagged cuts is very likely to split during installation.  Splitting would mean the sleeve must be removed; the field joint re-cleaned and then a new sleeve installed.  This is a difficult process as even sleeves that split because they weren't cut properly is a very difficult task.  Shrink sleeves are not designed to be removed; they are designed to say bonded to the pipe for the life of the line.
• On the financial side; the "savings" with cutting your own sleeves may not be as large as you think.  Let's pretend for a moment that you're working with a 16" OD Line.  The proper cut length for a 16" OD shrink sleeve is 56".  Pretend you are working with a 100 foot bulk roll of shrink sleeve material.  You will be able to cut 21 shrink sleeves (that are 56" long) from that 100 foot roll.  You will be left with a piece of shrink sleeve material that is 2 feet long.  You won't be able to use a 2 foot section of shrink sleeve on your 16" line - so that is going to be thrown out. That is 2% of that roll wasted (which eats into any cost savings you thought you were getting)

     If none of that dissuades you (I could have listed several more disadvantages to trying to cut your own sleeves); these are the shrink sleeve material types that I keep in stock:

• WPCT 11" wide
• WPCT 17" wide
• WPCT 24" wide
• WPCT 34" wide
• WPC100M 11" wide
• WPC100M 17" wide
• WPC100M 24" wide
• WPC100M 34" wide
  
• WPC120 11" wide
• WPC120 17" wide
• WPC120 24" wide
• WPC120 34" wide
• HTLP60 11" wide
• HTLP60 17" wide
• HTLP60 24" wide
• HTLP60 34" wide
• HTLP80 11" wide
• HTLP80 17" wide
  
• HTLP80 24" wide
• HTLP80 34" wide
• DIRAX 
• ROCS

An example of a /UNI sleeve (1 piece, pre-cut, properly sized, closure attached)

     Buying cut piece sleeves, on the other hand, is simple.  Open the box.  Set aside the installation sheet for your crews to reference.  Grab one sleeve.  Install it.  Incredibly simple - everything is the right width, the right cut length, etc.  Much less can go wrong here.  

     So, say you want a WPC100M shrink sleeve for an 8" OD pipe and you want it in a 17" width.  You simply order:  WPC100M 8625-17/UNI.   Off you go.

The WPC100M is the material type (mastic sleeve designed to be used on pipelines that will operate at up to 176F (212F in some applications).  The 8625 is the diameter of the pipe in mils.  The 17" is the width of the sleeve (actually closer to 17.75") and the /UNI means the closure strip (WPCPIV) is already attached to the sleeve, making your installation simpler.

Have questions?  Reach out:  steve@jsicoatings.com  936/321-3333

Heat Shrink Sleeve Coating Thickness

Coating Thickness of Heat Shrink Sleeves

      When determining coating thickness of different heat shrinkable sleeve options, there are several things you will want to consider.  I will look at each individually below and then sum up at the end.  Those three components are:  Backing Thickness; Adhesive Thickness and (where applicable) Epoxy Thickness.  First up:  Backing Thickness.

     It is important to note that much literature for heat shrinkable sleeves will contain two different thickness for backing.  These two things are 'as supplied' and 'fully recovered.'  Some folks find these confusing so let me explain.  First of all - let's change gears and look at a really big rubber band like you might use for rehabilitation of a shoulder injury.  At rest (fully recovered) that rubber band is going to be at its thickest point.  Now stretch that rubber band out as far as it will go (or as far as it can go) and you will notice that it is thinner when stretched out (this can illustrate supplied thickness).  Relax the rubber band again and you will see the thickness grow back to its resting state.

     The supplied thickness of any particular shrink sleeve is that 'stretched' out version of the rubber band.  The fully recovered thickness would be that rubber band at rest.  Because of the nature of heat shrink sleeves:  acting as a vehicle for applying adhesive to a substrate and pressuring that adhesive into all cracks, voids, imperfections and step down areas, that heat shrink sleeve really needs to be able to shrink to something smaller than the substrate diameter.  So a shrink sleeve on a 6" pipe really needs to be manufactured in such a way that it will fully conform to that 6" pipe.  How is that done?  By making a shrink sleeve that would actually shrink down to something like 5.5"....IF IT WERE ABLE TO.  Because it is unable to on a 6" pipeline, the shrink sleeve applies its pressure to the adhesive; forcing a good bond to the substrate and the PE jacket; and holding that pressure throughout the life of the pipeline.  Based on all of that -- the 'fully recovered thickness of the backing' that you will see on a data sheet is very often going to be slightly thicker than what you would actually see during an install.  In the field; heat shrink sleeves simply do not 'fully recover' because the substrate does not allow it.  Hopefully that makes sense.

     When considering the adhesive thickness; generally only one data point is recorded: adhesive thickness as supplied.  This is an excellent and accurate number when purchasing a proven, high quality product like Covalence (Seal for Life / formerly Raychem) manufactures.  What is there to discuss beyond that?  Plenty.  The adhesive actually gets quite a bit thicker during installation.  How does that happen?  Let me give a slightly oversimplified example:  say you have a 10 foot section of WPCT material.  Now say you shrink that down fully.  When you are finished; that WPCT section is going to be something closer to 7.5 feet long.  This is because WPCT is designed to shrink 25% to 31% (so in reality, that 10 foot section could shrink to just under 7 feet long).  So the surface area of the PE crosslinked backing has diminished by 25+%; and now the adhesive thickness that was covering 10 feet of material will not be covering only 7.5 feet of material.  In theory; an increase in thickness of 25%.  But it doesn't end there.  When the shrink sleeve is installed, one of the purposes of the shrink sleeve is to force adhesive out at the edges of the sleeve; creating an impenetrable barrier that water and oxygen will be unable to permeate.  So some of that 25% added thickness will be lost; but certainly not all of it.  How much is left?  That is a complicated question as it will be hinged on how snugly the sleeve was wrapped around the pipe; how properly the pipe was preheated; how much the shrink sleeve was heated and shrunk; how much adhesive might have been pushed around when rolling the overlap area of the sleeve; etc; etc.

     Finally, we can look at epoxy thickness where applicable.  Products that utilize an epoxy are generally:  HTLP60; HTLP80 and DIRAX.  With some products; epoxy thickness is critical and difficult to manage.  With stand alone epoxies it is not unusual that you need to work up multiple layers of epoxy in order to achieve 30 mils; 45 mils or even 60 mils of thickness in order to meet whatever end user specification you are working from.  That isn't the case with our product.  With our products we are generally looking for a thickness of epoxy that would be measured in microns.  Certainly visible to the eye.  Certainly covering every single square millimeter that the heat shrink sleeve will touch (and beyond in order to act as an inspection tool for construction foremen).  But there is no difficult thickness requirement and really not even a thickness gauge required. 

     So there you have it.  More than you ever wanted to know about heat shrink sleeve coating thicknesses.  Tomorrow I will follow up with a post outlining data from some of our actual products. 

Raychem History

History of Raychem Corp.

  You may not know it, but there is a group out there called the Raychemers.  You see Raychem was such an incredible company to work for that many former employees have a real spot in their heart for all things Raychem.  Having been around this for many years (my Father worked at Raychem for 25+ years), the only thing I could compare it to would be the feelings someone has for their Alma Mater College, or the feeling someone might have for their fraternity.  Somehow, Paul Cook and the rest of his team were able to foster a work place environment that could recapture the freshness and the newness that generally not found in adult careers.  In any case, this months Raychemer Pennant (newsletter) found its way to my email inbox this morning and I wanted to share some of what was written.

     The first thing to catch my eye is a fascinating piece on the Raychem Technical Hall of Fame that seems to have been written by a Dr. Leon Glover:

Raychem Technical Hall of Fame

     Raychem was founded on January 1, 1957.  It grew rapidly by creating proprietary new products based on Radiation processing of polymers to meet critical and difficult industry needs for electrical circuit integrity in harsh environments.  Included in these initial products were irradiated wire insulation and heat shrinkable tubing.  Markets included Aerospace, Military, Automotive, Telecommunications and Electrical Power Generation markets.

     In 1968, Raychem acquired Chemelex leading Raychem to extend its radiation polymer processing technology to polymers filled with conductive carbon creating a family of "Self Limiting Heaters".  This technology was further extended to produce resettable switches forming the enabling technology for the "Polyswitch" Division.

     As Raychem grew into a world class Material Science Company, additional technologies explored, developed and taken to market were Heat Recoverable Metals, Piezoelectric Materials (Elographics), Silicone Gels (Geltek) and Liquid Crystals (Taliq). 

     Each year, Raychem devoted between 8 and 10 percent of sales into Research and Development resulting in thousands of new products based on the technologies listed above.  Research and Product Development labaratories, in addition to Menlo Park and Redwood City were established in Swindon, UK, Kessel-Lo, Belgium, Ottobrunn, Germany, Pontois, France and Japan.

     Manning these laboratories were an extremely creative and talented group of scientists and engineers who found innovative ways to use technologies to create new products. 

     In 1990, after Paul Cook retired, the technical leadership of the company proposed creating the "Raychem Technical Hall of Fame".  This proposal was accepted and the first "Hall of Fame" class was initiated on December 11, 1991.  This was followed by further inductions in June 1993 and February 1996.  Paul Cook was the first inductee recognized for his vision and technical leadership of the company.  Other inductees were:

December 1991:
Paul Cook
Robin Clabburn
Roger Ellis
Lou Frisco
Rosse Heslop
Vince Lanza
John Lyons
David Nyberg
Ed Stivers

June 1993:
Klaus Dahl
Leon Glover
James Jervis
Hans Lunk
Jean-Marie Nolf
Richard Penneck
Richard Sovish

February 1996:
Jack Harrison
Jun Ishioka
William Johnson
Daniel Magay
Noel Overbergh
Gerald Shimirak

Plaques with the names of each induction class were mounted in the lobby of Building J auditorium.  Unfortunately, these have been lost with the take over of Raychem by Tyco International and the demolition of building J.

     The last thing I would share from this newsletter is a Raychem in Review:  1976 snapshot (same newsletter but I am not sure who wrote / compiled this article).

Raychem Sales (1976 dollars):  $171,332,000
Raychem Income (1976 dollars):  $3,516,000
Income/Share:  $2.65
Number of Employees:  4400
Floor Space Occupied:  2,300,000 square feet

In the first quarter, Raychem received an order for the corrosion prevention tape for use on buried sections of the trans-Alaska pipeline.  This was the largest order in Raychem history.

Midway through the third quarter foreign currency valued dropped precipitously and simultaneously in several of the countries where Raychem's business was the greatest.

Sales of Chemelex products continued strong throughout the year, augmented by new customers for Auto-Trace self limiting heaters.

At year end, the decision was made to cease manufacture and sale of Stilan polyarylene polymer, resulting in an approximate 9.3 million dollar change to net earnings. 

The early work on conductive polymers produced the very successful Chemelex auto tracing self limiting heater.  With the cessation of Stilan operating substantial technical energies have been transferred to the conductive polymer area.  This should lead directly to the commercialization of a number of new products over the next few years. 

Raychem / Covalence Heat Shrink Sleeve Advantages

Advantages of Covalence Shrink Sleeves (formerly Raychem)

Demanding Applications

In order to protect metal pipe structures in contact with an electrolyte (soil, water) coatings need to have a high electrical resistance and low permeability to hydrogen and oxygen. 
The coating must also be physically strong and chemically stable.
Additionally, the requirements of particular applications, like high operating temperatures necessitate specific tailoring of all pipeline coatings, including heat shrinkable sleeves.

Optimal Solutions

To provide the optimal solution for each application, Raychem offers a range of products based on an irradiated crosslinked polyethylene carrier, combined with a hot melt or mastic coating applied in the factory to that heat shrink backing.
The main purpose of the crosslinked carrier (the actual heat shrink sleeve), called the backing, is to provide a strong barrier against electrical current, permeation and mechanical forces.
The adhesive assures long term bonding of the backing to the pipe and provides added electrical resistance (which is a good thing in spite of the propaganda you are regularly exposed to) and mechanical strength.
Thickness of the backing and adhesive depend on the application requirements. 

To sum that up:  Strengths of the heat shrink sleeve include (but are not limited to):
- Chemical Resistance of heat shrink backing and the selected adhesive
- Flow and fill of the hot melt adhesive or mastic sealant
- Mechanical Strength of the heat shrinkable backing (which can potentially be multiple layers and include fiber reinforcement)
- Electrical Resistance of both the backing and the adhesive.  A coating with no electrical resistance means your pipeline is going to rely on your CP system almost solely for corrosion prevention.  Why not just leave the field joints as bare steel if that is your goal?

Three Layer Coatings

For the increasingly common (in Europe, South America and Asia) three layer factory applied pipeline coatings, Raychem / Covalence has developed a three layer field applied field joint coating.  To provide a homogeneously coated pipe surface in the girth weld area, a layer of two component epoxy is first applied to the surface of the pipe.  A specially designed shrink sleeve is then applied over the wet epoxy. 
The three layer heat shrinkable coating system performs extremely well in resisting cathodic disbondment.  It also offers high shear resistance against soil load and consequently ensures long service life. 

High Reliability, High Performance

Raychem (now called Covalence) has more than 40 years of experience in the development and manufacturer of heat shrinkable products.  Continuous improvement ensures state of the art performance.  Approval by testing agencies around the world guarantees suitability for individual applications and field conditions. 
- Two layer and three layer constructions complement wide range of pipe coatings
- Top quality hotmelt, copolymer coated sleeves resist elevated pipe operating temperatures and soil stresses on all pipe diameters.
- Mastic coated shrink sleeves balance performance, economy and easy of installation.
- Three layer sleeves with epoxy primer and hotmelt copolymer have excellent resistance to both cathodic disbondment and hot water immersion, even at maximum rated operating temperatures.
- Fiberglass reinforced heat shrink sleeves withstand the high stresses of directional drilling
- Self-healing adhesive slow automatically repairs minor mechanical damage

Low Installation Costs

- No primer required for two layer heat shrink sleeve systemes - install directly on cleaned and preheated pipe surface
- No waiting for primers to cure.  The shrink sleeve is installed directly over the wet epoxy
- Simple tools such as a hand brush, power brush or blast cleaning and propane torches are used for installation of the heat shrink sleeve
- All products available as Uni sleeve construction.  Uni sleeve means the closure strips are attached to the shrink sleeve here in our shop allowing for quicker installation in the field and dramatically fewer field issues.
- Easy to understand installation instructions are shipped with every product; in every box of shrink sleeves.  Clear product labelling on the outside of the boxes allows rapid on site installation.

Premium Service with Joint Specialists

To place an order or inquire about products, contact us at 936 /321-333 or email to steve@jsicoatings.com  We pride ourselves on offering the best customer service in the industry with very quick turnarounds on information, pricing and delivery.

WaterWrap Weld After Backfill Heat Shrink Sleeves

Heat Shrink Sleeves for Weld After Backfill (WAB) 

     Water Wrap with PCI (permanent change indicator) is a two layer field joint coating system designed for corrosion protection of buried large diameter water pipelines operating at ambient temperatures.  The 2 layer construction consists of a visco elastic low preheat adhesive sealant and a thick walled radiation cross linked high density polyethylene with PCI (permanent change indicator). 

     Waterwrap is a wrap around heat shrinkble, ready to fit assembly for the corrosion protection of field girth weld joints in water distribution and transmission systems.  Waterwrap/B is compatible with standard pipe coatings.  Waterwrap can also be used for coating bare, replacement pipe sections and large radius bends.  Waterwrap System-B is designed to be applied with a minimum preheating and is ideal for large diameter pipe.  The installation is carried out directly on the cleaned and dried (preheated) pipe surface.  The use of 939 filler is required when the step down on the weld bead is greater than or equal to 1/4".  The filler 939 is a thick mastic like butyl rubber designed to fill and smooth transition areas.  The semi-tacky composition remains flexible and easily molded in place to conform around irregular shapes.  During installation, the heat shrinkable sleeve is wrapped around the pipe and heat is applied.  The heat activated backing contracts to form a tight fit around the joint eliminating entrapped air and filling the smallest of crevices with high quality, corrosion inhibiting visco elastic adhesive sealant.  The permanently cross linked polyolefin outer layer forms a tough barrier against mechanical damage and moisture. 
     This product does not give off toxic gas vapors, it is safe to use.  This product has a high modulus backing which offers greater soil stress resistance and a great overall performance.  Product is tough but flexible and displays high impact and penetration resistance.  Waterwraps high shrink force optimizes flow and fill of visco elastic adhesive sealant. which brings with it greater long term protection.  Low application preheat makes installation fast and easy. 

Cost Analysis Shrink Sleeves vs Epoxies

Epoxies versus Heat Shrink Sleeves Cost Analysis

     This is a fairly common question that comes up from contractors:  which is cheaper epoxies or shrink sleeves?  As with just about every question that comes up, the question really deserves a close, in depth analysis.  The truth is, I distribute two part epoxies (Powercrete and Denso) and I distribute heat shrinkable sleeves (Covalence formerly called Raychem).  I am very familiar with both products including their installation procedures and their material costs.  For the sake of this comparison I'm looking at our standard wrap around shrink sleeve designed for ambient temperature pipelines.  I'm also looking at a one of the most commonly used, hand applied two part epoxies on the marketplace. 

    Quick disclaimer: each product technology has its own unique set of technical advantages and strengths -- and each has its own unique set of challenges.  This article is dealing purely with the cost aspect.  

     In both cases I'm going to look at something simple like a 12" pipe.  I'm also going to assume an FBE coated line where the standard cutbacks are around 2-3 inches per side. 

     So the basics first, Material Cost:

List price of 2 part epoxy in a 25-30 mil thickness:  ~$11.80 per field joint

List price of a standard WPCT shrink sleeve in a 100 mil thickness:  ~$11.60 per field joint

     In addition, that epoxy cost is based on getting several field joints out of a single two part epoxy kit.  If there were factors that led to the inability of the installer to be efficient with the epoxy, that cost per field joint could double or even triple.  What are the factor that could cause an inefficient use of the epoxy (and thus a dramatic increase in material cost)?

• a right of way that doesn't allow for multiple field joints to be coated within a window of a few minutes
• hot temperatures that cause reduced pot life of the mixed epoxy
• crews not working quickly enough to use epoxy prior to cure
• ambient conditions requiring multiple coats of epoxy to meet specification

      Considering only material costs for an ambient temperature, standard drop in a ditch application pipeline- the shrink sleeves offer some monetary savings.  What does the picture look like when we begin to consider labor costs?  I'm afraid for these comparisons, I'm flying blind a bit.  I do not know what labor costs or equipment rental costs are; so rather than make things up, I will simply outline things so that you can use your own expertise to determine for yourself what effect these factors will have on overall coating cost. 

Surface Preparation:
WPCT can be installed on a wire brushed pipe surface in order to create a surface that is free of oils, greases and foreign material.

Epoxies must be installed on a grit blasted surface with the proper anchor pattern in the steel. 

Wire brush vs grit blasting - I have to believe the cost advantage here goes to shrink sleeves

Installation Time: 
This one can get a bit tricky as there are so many factors.  Looking at preheating the steel and wrapping and shrinking the sleeve properly, I'd estimate an installation on 12" pipe at ~4 minutes.

Installation time for the epoxy?  I honestly can't say as it will be heavily dependent on installer skill, ambient temperature, cure times, thickness applied per coat and how well that specific epoxy is hanging on the pipe. 

Install time - Again, I have to believe the cost advantage goes to shrink sleeves here.

Inspector Issues:
With shrink sleeves there are certainly things that can be (and should be) on an inspectors radar.  The inspector needs to be certain the pipe is being properly preheated prior to wrapping the sleeve.  The inspector needs to give a visual inspection to make certain there are no cold spots and that the sleeve shows adhesive flow on all edges.  If there are cold spots or if there is a lack of adhesive flow, the crew will need to reheat that shrink sleeve and correct those issues which can take 2-3 minutes.

With epoxies, the inspector needs to make sure that the coating thickness is correct and meeting the specification.  The inspector needs to be certain that any icicles are within the end users tolerance levels.  The inspector needs to be certain there is no cracking.  In cases where corrective action is required, the crews will need to remix more material, reapply it properly and if necessary add more than one coat to bring that field joint up to spec. 

Inspector issues:  Red flags on a shrink sleeve require a few minutes of time.  Red flags on epoxy are generally going to require more material (cost) and time.  The cost advantage here must go to shrink sleeves.

Repairs: 
Shrink sleeves by their very nature are very, very tough.  Beyond that, installers require no special equipment or training in order to properly apply them.  Every box includes a detailed installation instruction and all of the most important aspects of the coating (thickness, seal ability, etc) are outside of the installers control.  Shrink sleeves are very difficult to accidentally damage, and as a result, repairs are incredibly rare.

Epoxies can require repairs more often.  Jeeping the field joint can cause previously unseen holidays to appear.  Bugs can fly into the epoxy prior to cure.  Brushing up against the field joint prior to cure can cause damage.  Grass or pine needles or dirt or dust can be blown into the coating by the wind.  Any of those can require repairs.  Every repair requires more material be mixed which results in a higher material cost and a higher labor cost. 

Repairs:  Advantage has to go to shrink sleeves on this one. 

     So there you have it.  By my estimation, looking at a standard 12" pipeline, shrink sleeves are going to be less expensive in every single aspect; including material cost, labor cost, repair cost and surface prep cost.  I'm trying to figure out:  why does it seem like a 'commonly accepted' fact that two part epoxies are a more cost effective option than shrink sleeves?  I do not know (though I would say that when spray applying epoxies; this picture might look a bit different, but that is outside of my own personal expertise so I can't honestly comment on it). 

     Keep in mind, I understand completely that there are some specifications out there that allow ONLY heat shrinkable sleeves.  I also know there are specifications out there that allow ONLY two part epoxies.  My focus here is simply to say: if you are working on a project that contains an allowance for either technology; it is absolutely, positively worth your time to consider how each product technology (shrink sleeves and epoxies) will impact your profits on the line.  Looking at all of these considerations, one option could make for a job that is dramatically more profitable than the other. 

WPCT Shrink Sleeves

WPCT Wraparound Shrink Sleeves

     The original heat shrinkable sleeves designed to be used as corrosion prevention products on girth welds of pipelines were all manufactured as tubular products.  This mean the tubes had to be slipped into place before the pipe was welded up.  This also meant the tube had to slide far enough away from the welding area that the shrink sleeve wouldn't be damaged by weld splatter or excessive heat. 

     It was years until a wrap around shrink sleeve was developed.  What was the main problem?  How do you hold the sleeve in the 'shape' of a tube during the installation process and keep it in 'installed tube form' for the life of the pipeline?  The answer was to develop a closure strip which would do just that.

     Anyway, the WPCT wraparound shrink sleeve is an ancestor of those early, very first heat shrinkable wrap around sleeves.  There have been many improvements along the way.  WPCT right now stands for Wraparound Pipe Coating (with Thermal indicator).  (For a thorough explanation of what a thermal indicator is -- click).

     In its current form - WPCT is a product that is designed to be used on pipelines that will be buried or subea...AND will operate at or below 40C (~104F).  WPCT shrink sleeves can be manufactured for essentially any pipe size from 2.375" on up to 144" OD pipe or larger.  As a standard, WPCT is available in 11", 17", 24" and 34" widths and custom widths are available by request.

     Installation of the WPCT shrink sleeves is very simple.  After the weld is completed, the field joint area is cleaned with a power wire brush (or better).  The area that will be in contact with the WPCT sleeve (steel and adjacent pipeline coating) is then heated with a propane torch to at least 140F (often referred to as "hand hot").  The installer will then remove the release paper (exposing the aggressive, stick mastic) and wrap the WPCT shrink sleeve around the pipe snugly (no reason to leave a huge bag of slack in it).  This will result in the shrink sleeve overlapping onto itself.

     If you've purchased this WPCT material from us, you have a /UNI sleeve which means the closure strip has already been attached to one side of the sleeve.  This closure strip will go on the outside.  Heat that closure strip so that it bonds to the backing of the shrink sleeve forming a smooth tube.  Heat the closure with a propane torch so that the interior fabric reinforcement of the closure strip is able to begin showing (forming somewhat of a cross hatch pattern).  Once that is complete you are cleared to begin shrinking the sleeve (which ironically goes from a cross hatched pattern to a smooth surface). 

Weld Joint Coating on Pipelines Coated with FBE

Technical Comparison between FBE Powder and Heat Shrink Sleeves

1 - Introduction

     Both joint coatings are used in the field and both have their advantages and disadvantages with regard to materials and application methods.

 

1.1 - Weld joint coating with epoxy powder

     The application process is the following:

     a) clean the exposed steel by sand or grit blasting to a degree of cleanliness of SA3 (or better)

     b) provide, by the same operation and the selection of the abrasive, a surface roughness of 80 to 160 microns (as required by the epoxy powder supplier) in order to create an adequate anchor pattern for the epoxy layer to adhere to the steel surface. 

     c) eliminate all sharp edges with a file or mechanic tool (all thin film coatings need this special care as part of the surface preparation).

     d) clean both edges of the adjacent line coating with a  solvent, to remove all traces of dirt, debris, oil, grease or other contamination.

     e) preheat the joint, with due consideration to the ambient temperature and the thermal inertia of the steel mass, up to 220C, to obtain a perfect fusion of the epoxy powder particles amongst themselves and with the steel surface. 

     f) apply the epoxy powder with an electrostatic spray gun (or flocker)

     g) allow to cure

     h) check the result

     i) paint holidays in the joint coating with liquid epoxy or FBE repair sticks

 

1.2 - Heat shrinkable sleeves

     The application is the following:

     a) clean the exposed steel by wire brushing to a cleanliness of ST3 or alternatively SA2 or SA 2 1/2 (some products require more surface preparation than others).
     b) clean superficially the two edges of the line coating.
     c) preheate the joint area to 80-160C (depending on the manufacturer's recommendation)
     d) if applicable, precoat the bare metal and adjacent FBE with epoxy primer
     e) wrap sleeve and secure closure
     f) shrink the sleeve on the pipe
     g) inspect

2 - Comparison
     Both processes give excellent results, provided they are applied in accordance with all applicable instructions.  However, all site operations made to date with the epoxy powder spraying method have shown a major drawback:  the process is complicated and not really appropriate for some field conditions. 

2.1 - Methods
     Fusion bonded epoxy powder needs to be applied under specific conditions and using specialized equipment that can only be properly controlled in a plant and at a very complex technical level.  It is not at all easy to ensure this same performance level under field conditions.

2.2 - Equipment

2.2.1 - The equipment required for the fusion bonded epoxy powder joint coating is comprised of the following:
     - a refrigerated storage container (the shelf and storage life of the epoxy powder decreases rapidly at temperatures exceeding 20C)
     - a mobile grit / sand blasting unit, that can achieve the required anchor pattern.
     - a solvent storage outfit with fire extinguishers
     - a screening, recycling and conditioning installation (fluidized bed) plus a primary electric power source.
     - an induction pipe preheating system, including a special generator set (single phase, 800 or more cycles, special cables and an induction coil per pipe size.
     - powder spray equipment with electrostatic spray gun
     - control equipment for constant monitoring of temperature and gelling
Most of the above equipment utilizes electronic components that suffer from voltage variations, temperature excursions and vibration (coming from the generator sets on the same frame). 

2.2.2 - The equipment required for heat shrink sleeve installation is:
     - electric or pneumatic wire brushes, or a simple sandblasting outfit
     - propane torches with propane bottles, or a simple induction heating system

2.3 - Skill of operators
     The complex application procedure of fusion bonded epoxy powder requires highly qualified technicians for both, powder application and equipment maintenance.  The application of heat shrink sleeves is a matter of a few hours of training. 

2.4 - Necessary manpower
     All the various activities involved with the storage / feeding / reconditioning and application of the epoxy powder obviously require much more manpower than the simple shrinking of sleeves.  Even when labor is inexpensive, this may become an important issue.  Very often, sites are in remote locations and only limited space is available in the living quarters. 

2.5 - Ease of creating supplementary crews
     If, during the construction period, more application crews become necessary, it is very easy to put together another crew of skilled heat shrink installers, as there is virtually no supplementary equipment needed.  On the other hand, every supplementary crew for epoxy powder needs new highly skilled specialists and a complete set of the equipment described in 2.2

2.6 - Life time of raw materials
     Epoxy powder has a limited life time, depending very much on storage and handling conditions.  A heat shrink sleeve can be kept in store for an unlimited period of time and at temperatures up to 55C

2.7 - Preheating temperatures
     The preheating temperatures for epoxy powder are in the range of 220C.  To obtain a uniform thickness, a uniform preheating temperature is an absolute must.
     Preheating temperatures for heat shrink sleeves are in the range of 80-160C, depending on the adhesives used.  In case of a liquid epoxy first layer, the preheating needs only to be at 60C for all adhesives.  Preheat temperatures up to 100C can be easily achieved with propane torches under all field conditions.

2.8 - Tie-ins
     For the epoxy powder, every tie-in crew also needs a complete set of equipment.  The equipment for tie-ins needs to be even more mobile than the standard joint-protection set. 

2.9 - Back-up equipment
     For the epoxy powder process at least one complete spare set of equipment needs to be kept on hand to avoid risking the complete shut down of the job. 



Heat Shrink Sleeve Benefits

Heat Shrinkable Sleeve Benefits (and Assets)

     What are the technical assets of heat shrinkable sleeves?

1. Covalence shrink sleeves have adhesives compatible with all plant coatings.
2. Heat shrink sleeves are shrinkable!  They have the ability to conform to irregularities (weld beads, coating transitions, etc)
3. Mastic shrink sleeves have self healing characteristics.
4. Shrink sleeves are resistant to damages
1. Resist backfill damage
2. Resist damage from J tube placement of pipe
3. Resist roller damage in offshore lay barge applications
4. Resist pipe spooling in reel bare operations
5. Heat shrink offers cathodic disbaonding resistance
1. Ability to resist cathodic disbanding under a variety of conditions.  Shown itself to withstand disbanding at hydrostatic pressures in deep water.
6. Shrink sleeves have a non-melting backing
1. Ability to withstand hot mastic pour systems at mastic temperatures of 200C plus
2. Unaffected by polyurethane foam where temperature generation can reach 300F
7. Heat shrinkable sleeves are designed to last as long as your pipeline does
1. Shrink sleeve backing is made with UV stabilizers and antioxidants
8. Heat shrink sleeves offer excellent electrical properties (this is a good thing in spite of what 'the other guys' say....over and over and over and over.
9. Joint Specialists is able to offer product support after the purchase of product

Raychem Wrap Up Newsletter

Raychem WrapUp Newsletter

     I came across an old Raychem newsletter yesterday.  I suppose that is one of the advantages of being from a family that has been involved with Raychem (and Covalence) heat shrinkable sleeves since the mid 1970's; you never know what you're going to find.  Open up an old box or a long ignored drawer and you're likely to come across an old product data sheet; hand scribbled notes from a weekend phone call; a copy of an old technical paper or even Volume 1, No. 1 of the Raychem WrapUp (which might be the only volume ever made and the only copy still in existence (it is in mint condition so if you're into this kind of thing, feel free to make me an offer!)

 

     This was a single sheet (front and back) newsletter thrown together by Bill Mannion who was apparently the head of the division for a few years way back when.  Bill wrote the first article of the page.  In the first article - there is one bit I absolutely LOVE.  Bill says that since so many folks within Raychem travel so much; he is planning to write a little guide to restaurants and hotels around the world so that folks can know where to eat and stay.  One of the restaurants he mentions is USA Seafood in Philadelphia and he goes on to say "the lobster is quite good" there.  Can you imagine a corporation in this day and age, whose division head tells his employees to make sure they try the lobster next time they are in Philly??

 

     Other articles in this newsletter include:

- Raychem's presence at ASHRAE (American Society of Heating, Refrigeration and Air Conditioning Engineers) at which their greatest attraction in the booth was our TWDB product. 

 

- Raychem introducing the "Real Seal" which was (apparently) an advertising campaign designed to shed light on Raychem's sealant technologies.

 

- A write up/feature on Raychem's business in Brasil and how they were beginning to take over as the industry leader there.

 

- A report on upcoming sales tools including literature, movies (available in 16mm and cassette!) and some industry focused brochures (gas, construction, district heating).

 

- An analysis of the year to date numbers versus plan (at that moment the world was at 110% of plan and expected to finish at 135%)

 

     The most interesting article to me though was a case study and project update on the LOOP project which I will be tackling tomorrow.  So, stay tuned!

HTLP Wrap-Around Heat Shrink Sleeve & Epoxy System

HTLP Wrap-around Sleeve & Epoxy System

The most widely used girth weld protection system for three-layer coated pipes.

Product description:

HTLP60, HTLP80 field-joint coatings. 

Construction: Three-layer system:  

First layer: Liquid epoxy, solvent-free two-component. 

Second layer: High shear strength copolymer adhesive. 

Third layer: Radiation cross-linked, high density polyethylene with PCI   (Permanent Change Indicator). 

The HTLP system is a wrap-around heat-shrinkable sleeve which replicates the structure and performance of mill-applied three-layer PE coatings. HTLP also has excellent compatibility and has been extensively used on many other mill-applied coatings. By far the majority of the girth welds worldwide on three-layer coated pipes, diameters up to 100" (DN2500), have been coated with HTLP.

During installation, the epoxy is applied to the prepared pipe surface and the heat-shrinkable sleeve is immediately wrapped around the joint over the wet epoxy. Heat is then applied to the sleeve which shrinks to form a tight fit around the joint. While curing, the epoxy forms strong mechanical and chemical bonds to the pipe surface & to the copolymer adhesive layer. The radiation cross-linked outer layer forms a tough barrier against mechanical damage and moisture transmission.

Product features/benefits:

 • Fully resistant to shear forces induced by soil and thermal movements. The HTLP is tough & lasts as long a 3-layer, mill-applied coating

.• Sleeve applied over wet epoxy---allowing formation of strong mechanical & chemical bonds. Allows fast application, combined with high performance!

• Superior cathodic disbondment and hot water immersion resistance. Offers the optimum barrier protection against corrosion.

• Fully reconstructs the coating of three-layer coated pipes. Thus, the HTLP allows the pipeline to have a virtually monolithic coating system. 

• Dimpled backing provides a “permanent change" indicator for application of heat. Ensures correct application heat & allows easy post-heat inspection. Reliable inspectability at any time.

Product selection guide:

HTLP60 

Max operating temperature: 65°C (149°F)  

Compatible line coatings: PE, PP, FBE, Coal Tar 

Min preheat temperature: 70°C (158°F)

Recommended pipe preparation: SA 2½  

Soil stress restrictions: None

Performance: EN 12068; Class C50 

HTLP80

Max operating temperature: 80°C (176°F)  

Compatible line coatings: PE, FBE, Coal Tar 

Min preheat temperature: 70°C (158°F)

Recommended pipe preparation: SA 2½  

Soil stress restrictions: None

Performance: EN 12068; Class C60 UV; Class C80 UV

Heat Shrink Pipe Coating

Heat Shrink Pipe Coatings

     Heat shrink pipe coatings have been in use for more than four decades (along with heat shrink used for wire splicing, cable repair and many other applications).  For most of those decades, Raychem Corporation was THE industry leader in heat shrinkable technologies; led by their visionary leader: Paul Cook (who essentially commercialized and popularized radiation crosslinking and radiation chemistry).  The rest, as they say, is history. 

Here we see a field joint, just prior to heat shrink sleeve installation.

     Though the most obvious use for a heat shrink sleeve is on polyethylene coated pipe (as seen in the photo above), by far the most common pipeline coating combination is fusion bond epoxy (FBE) as the mainline pipeline coating and heat shrink sleeves as the field joint coating.  We sell (literally) hundreds of thousands of heat shrink sleeves per year - and I can honestly say that ~90% of those will be used on FBE coated pipelines. 

     When determining what specific heat shrink sleeve material to use on your pipeline girth welds (which is hopefully happening very early in the specification process...rather than happening while construction crew is standing on a pipeline spread staring down at some welded pipe joints....) it is important that you are making an informed decision.  There are number of factors that are very important...such as:

1. Pipeline operating temperature (once the line is in service - sometimes called Design Temp)
2. Outside Diameter of the pipeline (hopefully this is an easy one!)
3. Factory applied mainline pipeline coating and cutback sizes
4. Soil conditions (rocky? sandy? clay? subsea? above ground?)

     If we have access to that information, we have a good head start on making sure you are going to be using an appropriate material.  The fastest way to a coating / corrosion problem is to select and use an inappropriate product for your pipeline.  

Heat Shrink Sleeves as Pipeline Coatings

Heat Shrink Sleeves for Pipelines

    Heat shrinkable sleeves have been used for many years as the primary corrosion coating for field joints (also called girth welds) on pipelines.  Do you need a refresher on what girth welds and field joints are?  As I've documented elsewhere in this blog (WPCT use history) Raychem (now called Covalence) shrink sleeves have been the market leaders for decades.  There are very literally millions and millions of pipeline field joints coated with heat shrink sleeves and the truth (which some big spending, vocal spin doctors don't want you to know) is that heat shrinkable sleeves (Raychem in particular) have been incredibly reliable pipeline coatings.  Heat shrink sleeves have offered excellent corrosion prevention to pipelines of all sizes.  If you've seen the GTI field joint coating test results - then you know that what I'm saying is true.  Heat shrink sleeves were generally ranked #1 (tied with FBE) in both clay and sandy soil.  Yes, you read that correctly:  NUMBER 1.  Compare the equipment and labor costs of putting FBE on your pipeline field joints with the material and labor cost of putting a heat shrink sleeve on your field joint....then go read the GTI report....then go ask your buyers why you've been needlessly spending on field joint coating to the tune of hundreds of thousands of dollars per year.

The front page of the amazingly thorough GTI field joint coating study

      I know what you're thinking if you've read this thread.  You're thinking "WHAT?  That can't be!"  I hate to break it to you, my friend...but it is true.  It is true - and its proven.  In case after case in that GTI study heat shrink sleeves ranked #1 and showed no signs of corrosion.  Meanwhile other "technologies" (I put the word technologies in quotes because some manufacturers out there are actually a lot better at marketing and story telling than they are at manufacturing quality pipeline coatings) performed so poorly in that GTI test that it is hard to understand how they sell anything!  But, I guess we've all known that advertising works -- that marketing works -- that if we hear something enough - we'll begin to believe it.  I think it was Lenin (the Russian; not the Beatle) who said "a lie told often enough becomes the truth."  

    If you're skeptical, contact GTI yourself and purchase your own copy of the report.  www.gastechnology.orgwww.gastechnology.org

Yellow Shrink Sleeves

Question:  Do you stock or sell yellow shrink sleeves?

Our shrink sleeves are black in color; fully UV resistant.

VERSUS

Other shrink sleeves on the market are yellow

Answer:  NO!  We stock and sell ONLY Covalence (formerly Raychem) heat shrinkable sleeve products.  They have always been black and have never been yellow.  Covalence shrink sleeves have by far the longest, most successful use history on the market (in the world) today.  Why aren't you buying the better product??  I think you'll be surprised to find that with Covalance / Raychem you get a better, more proven product without even spending more for it!

Shrink Sleeve Installation Tools

Shrink Sleeve Installation Tools

Question:  What tools are required for Covalence heat shrink sleeve installation?

Answer:  Ignoring the need to clean the pipe, Covalence heat shrink sleeves do not require

any special tools during installation.  Here is what is needed:

- A means of measuring preheat temperature.  This could range from something as 

sophisticated as a pyrometer with roller probe; to something

as simple as a temp stick.  

An example of temp sticks for different temperatures

 - A broad flamed torch (Covalence shrink sleeves cannot be shrunk

using an acetylene torch or a welding torch).  Our torches are sold as a kit

which includes a torch with a pilot lights; a regulator with a pressure guage

and a thirty foot long hose. 

A JS-2601 Torch Kit - available at JSI

- A long handled silicone roller.  This is used after installation to roll the overlap area

and can be used in the event that any air has become trapped (which could be

caused by poor application).  

A long handled roller; used during heat shrink sleeve installation

(Keep in mind that the contractor or end user will need to supply their own propane tanks for installation) 

Heat Shrink Sleeves: Most Dangerous Installation Error

  Question:  What is the most dangerous installation error when installing a heat shrinkable sleeve?

  Answer:  I'm going to overlook things like 'failing to clean the pipe' and 'failing to preheat the pipe'.  The most dangerous installation error is an installer who simply fails to care for the bottom of the pipe.

  Pipeline spreads are often NOT pretty.

A fairly typical (maybe even a 'good' pipeline spread.

 As you can see, there just isn't very much room underneath the pipe.  But still, the bottom half of the pipeline must still be cleaned and preheated.  In addition, the bottom of the sleeve must be shrunk and shrunk appropriately!  This same potential problem exists for any coating of course; working a liquid epoxy to prevent icicles can be even more challenging.

In any case, anytime an inspector asks me "what should I be looking for" one of the first things out of my mouth is that he's almost certainly going to need to get his knees dirty as he'll be crouching down under that pipeline to make sure the sleeve has been properly shrunk on the bottom of the pipe (and he/she needs to be familiar with this page!)

 

Installing Shrink Sleeves: How Important Is Pre-Heat?

     Another common question:  How Important is Pre-Heat?

     Short answer:  ABSOLUTELY CRUCIAL

     Long answer:  When installing a heat shrinkable sleeve as a field joint coating, you are doing so for one reason and one reason only.  You are protecting that field joint (girth weld) from corrosion.  Of course, the idea is, that if you can seal that field joint in a way that prevents water and oxygen from reaching the bare steel; then it will be impossible for corrosion to occur.


     We do this by installing a heat shrinkable sleeve that is coated with a sealant or adhesive of some kind.  If we can install that sleeve so that we get the best possible bond between sealant and bare steel (and factory applied coating) then we begin the life of that field joint from the very best possible position:  properly coated and protected.

     Of course the first step of installation is making sure we've achieved the proper cleanliness standard on the bare steel.  Different adhesives will have different requirements there and I won't discuss them here (but I did touch on surface prep for WPCT here).  The next step however is preheating the steel (and adjacent factory applied line coating) to the proper temperature.  Why is this necessary?

     Any hot melt adhesive or mastic coated shrink sleeve will have an optimum temperature at which the adhesive bonds to the substrate.  When we look at it very closely, we must create an environment where the bond-line reaches a temperature sufficient for ideal bonding.  The bond-line is that area where the hot melt adhesive of the mastic come into contact with the substrate (pipeline).  That interface is critical.

      Even though there is a significant amount of heat put into a heat shrink sleeve during the installation process; when you consider the heat insulation properties of the heat shrink sleeve and when you consider that the steel pipe will act as a heat sink (carrying temperature away from the girth weld as it acts to spread any elevated temperature through the steel in the immediate area) it isn't possible to actually achieve the necessary bond-line temperature exclusively using heat from the sleeve shrinking itself.

     As a result, the steel must be preheated.  This assures that the bond line temperature is met and that the adhesive/steel interface will be properly prepared for the bond to occur.  All Covalence heat shrink sleeves will be supplied with an installation sheet in each box.  No matter the product; there will be a 'minimum recommended preheat temperature' listed on that installation sheet.  It will certainly cause no problem to heat higher than that; with two exceptions.

- When installing a shrink sleeve system that utilizes a liquid epoxy (DIRAX, HTLP60, HTLP80, etc) it is important to keep the preheat temperature down below 200F.  Installing S1301M epoxy on a pipe that is heated above 200F will result in some smoke - and result in the epoxy more or less flash curing (which we want to avoid since we want the epoxy chemically bonding with the sleeve adhesive; and that can't happen in the epoxy cures "early")

- Most all shrink sleeves (all PE shrink sleeves anyway) shrink at ~267F.  We would not want to preheat (most of the time) to a higher temperature than that, as it could result in the sleeve shrinking before the installer is ready (as an example, before the closure has been secured).