Dirax Wrap-Around Heat Shrink Sleeve

Dirax Wrap -Around  Sleeve and Epoxy System

 A high performance fiberglass reinforced sleeve specifically designed for girth weld corrosion protection on pipes used in directional drilling applications.

Product Description:
DIRAX field-joint coating for directional drilling.
Construction: Three-layer system:

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

• Second layer: High shear strength copolymer adhesive. 

• Third layer: Thick, fiberglass reinforced, radiation cross-linked polyethylene.

Additional component: Wear Cone as extra protection against pull-through forces, of the same construction as the main sleeve.

The DIRAX system is a wrap-around heat-shrinkable sleeve reinforced with fiberglass. DIRAX is designed to protect girth welds against corrosion and is the optimum joint protec-tion for PE and FBE coated pipes used in directional drilling applications. The reinforcement gives the backing greater wear resistance.

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 bondsto the pipe surface & to the copolymer adhesive layer. The radiation cross-linked outer layer forms a tough barrier against mechanical damage and moisturetransmission. A wear cone is then applied over the leading edge of the sleeve. Note: Dirax is not suitable for "Push Through" applications.


Product Features/Benefits‡:

• Highly resistant to shear and peel forces induced by soil and thermal movements. The DIRAX is tough! ‡
• DIRAX offers abrasion and wear resistance at pull-through comparable to mill coatings. Provides a monolithic coating system.‡ 
• Wear cone protects leading edge of sleeve against pull-through forces. Provides additional strength and security---increases reliability. ‡ 
• Sleeve applied over wet epoxy---there are no curing or waiting times / formation of strong mechanical & chemical bonds Allows fast application---saves time! Ensures high performance!‡ 
• Superior cathodic disbondment and hot water immersion resistance. Offers the optimum barrier protection against corrosion.‡ 
• Pre-attached closure patch Allows fast and easy application. ‡ 
• Low preheat requirements Makes installation faster and saves time.

 Product Selection Guide:

Max operating temperature  - 60°C (140°F)
Compatible line coatings - PE, FBE
Min preheat temperature -70°C(158°F)
Recommended pipe preparation - SA 2½
Soil stress restrictions - None
Performance - EN 12068 Class C60

Product Thickness:

Backing (as supplied)  1.85 mm (0.073 in.)
Backing (fully free recovered)  2.3 mm (0.091 in.)
Adhesive (as supplied)  1.2 mm (0.047 in.)
Wear cone (incl. coating) (as supplied)  3.05 mm (0.12 in.)

Product Properties:

Chemical Resistance followed by Bursting Strength
Chemical Resistance Conducted for 168 hrs in 0.1N Nacl, 0.1NH2SO4
Resistance to UV radiation followed by Bursting Strength

Ordering Information:

DIRAX type products are available: as a kit, containing: -

• a Uni-sleeve (pre-cut sleeve with pre-attached closure patch) 
• a wear cone (also pre-cut with pre-attached closure patch)

Dirax is installed with S1239, S1301-M 2 and S1401  component epoxy primer which has to be ordered separately.

Best Field Joint Coating

     The  we live in focuses primarily on a single thing.  What is the cheapest and easiest thing that I can use?  It isn't always the case; and I am certainly being a bit unfair by saying that - but it is something I've seen again and again and again  in the last 13 years (my time in the pipeline world).  For many decision makers; cost is all that matters: "buy whatever is cheapest...it's all the same." 

All Field Joint Coatings AREN'T Created Equally

     So, when I do get the comment "I want whatever the best coating is - this pipeline is too valuable to scrimp on the field joint coatings" I tend to sit up and take notice.  Here is a person who cares about the future of this pipeline.  Here is a person who is committed to doing their best job possible; even if they are no longer with this company through the life of the line.  Here is a person with integrity.  Here is a person who cares about the long-term...not just about moving on to the next project or claiming that next promotion.

     In cases like this, where the request is for the "best" AND where we don't have an issue with elevated operating temperatures; the answer is clear.  The best possible field joint coating is ROCS.

The ROCS heat shrink sleeve system is absolutely unmatched in the coatings world.

     What you see here is a picture of the ROCS shrink sleeve.  The pattern you see is the fiber mesh (which is woven between two layers of HDPE, heat shrinkable backing.  The other side of this sleeve is a high shear adhesive.  All of this is installed on Covalence's S1301M liquid epoxy which chemically bonds with the adhesive of the ROCS shrink sleeve in order to form a truly cohesive field joint coating.

     Since the ROCS shrink sleeve system utilizes both a heat shrinkable sleeve and a liquid epoxy bonding agent; it literally offers the best of both worlds.  The liquid epoxy gives the coating system superior cathodic disbondment properties and sheer resistance.  The fiber reinforced shrink sleeve gives the coating system excellent electrical resistivity properties; superior abrasion resistance and fantastic penetration resistance. 

     Like all things in life; you get what you pay for.  The ROCS field joint coating system is expensive on the front end, during construction.  But the truth of the matter is that leaks, repairs and corrosion problems are incredibly expensive.  Taking a line out of service can cost almost a million dollars per day (as seen here).  There must be a point where 'cost' is not the number one factor when selecting a field joint coating; are we there yet?

DIRAX 24" Wide

DIRAX Shrink Sleeves for Road Bore Pipe

DIREX / DIRAX

          I think it has been well established that pipe that is involved in a road bore is just about the 'scariest' pipe there is.  Here you have both a factory applied coating - and a field joint coating - that are installed and inspected, and then we wave goodbye to that section of pipe as it is dragged down into a deep hole and never seen again.  Sure, that pipe will have an inspection pig go through it.  Sure, that pipe will be covered by some kind of a CP system (and it will be possible to detect current load increases if a corrosion problem occurs), but really - once that pipe leaves the sunshine and enters the darkness; you are pretty much depending on those coatings to survive and do their job throughout the life of the pipeline.   If they are damaged during the bore; you won't know until it is far, far too late.  That's why you pay for expensive pipe coatings like Powercrete on top of FBE or dual layer FBE.  That's why you should consider a product like DIRAX for your field joints. 

This is the DIRAX shrink sleeve as supplied.  As it is shrunk, it looks even more like alligator skin and is just as tough!

     DIRAX is installed on top of our S1301M epoxy primer.  The epoxy has been specially formulated to bond both physically and chemically to the adhesive of the DIRAX shrink sleeve system.  It works.  When fully (and freely) recovered; the backing of the DIRAX is 2.3mm thick.  That includes a layer of fiber mesh woven between two layers of polyethylene (fiber reinforced is kind of a big deal).  DIRAX is sold as a kit, which includes the shrink sleeve for coating the field joint (in a 12", 17" or 24" width); S1301M Epoxy and a 3" wide leader strip.

     Now getting back to where we started...the DIRAX is installed on the field joint and it needs to be wide enough to coat all bare steel and overlap onto the factory applied ARO by at least two inches per side.  In many cases, this can use the 12" wide sleeve - but some users....some users who know how scary it is that a coating cannot truly be inspected after being involved in a road bore -- those users who believe that using the best possible coating is important enough to spend a little extra - those users typically use a 24" wide DIRAX.  They know that a few extra dollars on the front end of a pipeline project -- in order to avoid the incredibly costly replacements, spills, corrosion problems and damage - is well worth it (not to mention that you can't put a price tag on restful sleep at night!).  People who want the best use DIRAX.  People who are want to take their absolute best shot at coating that field joint in the best possible manor - use DIRAX in a 24" width. *


*Let me be 100% clear and forthcoming.  I know from experience that 12" wide and 17" wide DIRAX sleeves do exactly what they are supposed to do.  I know that they survive the bore without damage and without being displaced.  I know that they continue to offer corrosion protection to those field joints for the life of the pipeline.  I know it because it has been done -- thousands of times -- and the number of problems I've heard about is exactly ZERO.  Some people just like to be extra cautious - they want to be able to look back someday and say "I did EVERY POSSIBLE THING I COULD HAVE" - and there is nothing wrong with that.  It's natural in many cases.  Why do people wear a belt AND suspenders?  Why do cars have seat belts AND air bags?  Why do my jeans have a button AND a zipper (what ever happened to button fly jeans anyway?)  Why do we have a lock, and a dead lock, and a chain, and a security system on our homes?  Because being certain carries great value with it.