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Monday, March 7, 2016

DIRAX and Protal Installation

Raychem / Covalence DIRAX
Installed On Cured Protal 7200

Materials and Equipment Required:
·         Appropriate sized DIRAX kit
·         Approved adjustable Propane Torches w/ regulator
·         Temperature measuring equipment (contact pyrometer)
·         Standard safety equipment
·         Heat resistant gloves
·         Silicone roller

protal and dirax

Lightly abrade Protal 7200 and ARO coating adjacent to field joint, then use a solvent to remove all oil, grease, mud and dust from the area where the DIRAX will be installed.
shrink sleeves and denso

Mix the S1301M Epoxy Primer.  Pour smaller can into larger can.  Mix for approximately 1 minute.  If working in cooler weather, keeping epoxy inside of a truck (at a slightly warmer temperature) can make the epoxy easier to mix.
protal on dirax

Using a propane torch with a broad, bushy, yellow flame, gently preheat Protal 7200 and adjacent ARO where the DIRAX will be installed to a temperature in the 160F range (minimum:  140F; maximum: 180F).  The purpose of this preheat is to most efficiently use the S1301M epoxy primer, minimizing wastage.  Check preheat temperature with a contact pyrometer. 
protal with dirax

Use the supplied applicator pad to apply the mixed epoxy primer over the entire surface to be covered (Protal 7200 and ARO).  Note:  When installing 12” wide sleeves on a 12” OD pipe – each individual epoxy kit contains enough epoxy to coat 3 field joints.
denso with dirax

Immediately after application of the S1301M epoxy primer, and while the primer is STILL WET, loosely wrap the DIRAX sleeve centrally around the girth weld.  Wrap the sleeve (adhesive side down) around the area to be coated.  Make sure the DIRAX sleeve wraps around the pipe and overlaps itself by at least 2 inches.  
epoxy with dirax

Gently preheat the inside layer of the adhesive layer just next to the closure strip for 2 seconds and press it down on the sleeve end on the pipe to form a tube (making it stick to the other end of the sleeve).
denso heat shrink sleeves

Using the approved torch, with a broad, bushy, yellow flame, start heating the closure area.  As you see the closure begin to ‘soften’ pat it down firmly with a gloved hand.  Continue heating and patting every few inches until the whole patch area is finished.  As the closure is properly heated, you should see a light cross hatch texture appearing in the closure.  
protal and dirax

Start heating (with a broad, bushy, yellow flame) the sleeve at the side of the leading edge (the side toward where the bore hole is).  Move the torch continuously CIRCUMFERENTIALLY (up and down) in a paint brush motion all the way around the sleeve.  Work (moving torch up and down) from one end of sleeve; toward middle – then toward other end of sleeve – always UP AND DOWN with yellow flame contacting the sleeve.
shrink sleeves and protal

Upon completion of “shrink”, while the DIRAX is still hot and soft, run a small hand roller over the overlap area (where one layer of sleeve overlaps onto the other layer of sleeve, to push out any potential trapped air.  Pay particular attention to the weld and cutback area.  Reheat any area if necessary.  At this stage is when the temperature reading can be taken on the backing of the sleeve with a contact pyrometer.  Sleeve backing temperature is not to exceed 350F which can be easily achieved with installer taking care and working with Torch at proper output levels (but must exceed 267F or the sleeve will not shrink).
both dirax and protal

Main DIRAX sleeve is complete when:  sleeve has fully conformed to the pipe / Protal and adjacent ARO; there are no cold spots or dimples in the sleeve surface; there are no major blisters on the sleeve surface, adhesive flow is evident on both edges after sleeve is cool. 
sleeves on denso?
It is now time to install 3” wide leader strip on the side of the sleeve that will go into bore hole first.  That area should still be at least 160F (but if not; it will be necessary to re-pre-heat).

Wrap the leading edge / wear cone over the transition between the DIRAX and the ARO.  Make sure the closure for the wear cone is placed away from the main sleeve closure.  Install this wear cone the same way as the DIRAX sleeve – wrapping around pipe to overlap onto self; securing the closure and then shrinking the wear cone with a broad, bushy, yellow flame.  
protal on sleeves?

Smooth down any edges of the sleeve with the silicone roller.  Sleeve is fully recovered when: it is fully conformed to pipe surface / Protal / Denso.  There are no cold spots; dimples.  Profiles are visible beneath sleeve.  Adhesive flow evident on all edges after sleeve has cooled.  Sleeve must be cooled to ambient temperature (and epoxy cured) before it should see soil stresses. 

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