DIRAX Installation Guideline
DIRAX is a relatively simple installation. It does not require any significant skill. A few of the common tips that we say over and over and over at training sessions are: 1) You want a broad bushy yellow flame to shrink the sleeve (this requires that you have a regulator of some kind) and 2) Your torch needs to ALWAYS be moving - you can't stay in one spot for too long and you want to make sure it is the yellow flame in contact with the sleeve; not the blue flame and not the 'clear' flame right where it comes out of the torch.
Clean exposed steel and adjacent pipe
coating to be covered by DIRAX sleeve.
Remove all contaminants such as oil. Use a
solvent that contains no grease or oil type
materials.
If not factory beveled, chamfer the adjacent pipe
coating to an angle of preferably 15°, maximum
30°. Inspect the edge of the existing pipe coating.
Disbonded sections have to be trimmed of and the
coating edge has to be beveled again.
To avoid possible contamination, it is
recommended to use a scrape
Grid blast or sand blast the steel surface to
remove loose and foreign materials. The
surface should be cleaned to SIS 055900 -
SA 21/2
Grid or sand blast the adjacent pipe coating
over a distance of at least 200 mm (8"). The
total width should be approximately 50 mm
larger than the width of the Raychem
supplied DIRAX sleeve.
Note: prior to blasting, it is recommended to
preheat the exposed steel to 40 - 50° C to
avoid flash rust formation
Wipe the surface to remove dust and
remaining blasting material. Use a clean dry
cloth or air blow
Dose the two component Raychem epoxy. Use
pre-dosed Raychem epoxy kits or use Raychem
calibrated epoxy pumps.
For pre-dosed Raychem epoxy kits, pour content of
can B into can A and mix for approximately 1
minute. For easy disposal, it is recommended to
pour this mixture back into can B and mix for
another 30 seconds. As such, the remaining epoxy
in both cans will cure and can be easily disposed off.
Follow local regulations for safe disposal.
40°C
20°C 2 min
Mixed epoxy primer has a pot life of approximately
30 minutes at ambient temperature. As long as the
epoxy primer is still liquid, it may be used.
For easy mixing and dispensing, the epoxy primer
should be used at a temperature of min. 18° C.
When necessary, keep the epoxy primer at a
heated place or use a Raychem epoxy heater.
Preheat the bare steel surface and adjacent
coating to minimum 70°C (160°F), using
propane torches. Adjust flame length to
approximately 20" (500 mm). In cold
conditions extra heavy preheat torches can
be used. Check preheat temperature with a
contact pyrometer
Using the supplied applicator pad, apply the
mixed epoxy primer over the entire surface to
be covered. (When PE line coating is used,
no primer should be applied over the
polyethylene line coating.)
Immediately after application of the epoxy
primer, and while the epoxy primer is still wet,
loosely wrap the DIRAX sleeve centrally
around the welded joint.
If present, remove the protective release
plastic from the adhesive side of the DIRAX
sleeve. Wrap the sleeve (adhesive side down)
around the area to be coated. Make sure the
sleeve overlaps the end of the inner layer by
at least 50 mm (2”).
Preheat the inside adhesive layer just next to
the closure for a few seconds, and press
down on the sleeve end to make it stick to
the other end.
Using a Raychem propane torch with a flame
length of approximately 500 mm (20”), start
heating one end of the closure area.
Immediately pat it down firmly with a gloved
hand. Continue heating and patting every
10 cm (4”) until the whole patch area is
finished.
Start heating the sleeve at the side of the
leading edge, the side that first comes in
contact with the ground forces. Move the
torch continuously in a paint brush motion all
the way around the sleeve
After you have finished heating the side at
the leading edge, recover the remainder of
the sleeve by heating toward the other end of
the sleeve
During shrink down, check adhesive flow with
finger occasionally. Wrinkles should
disappear automatically
After the DIRAX sleeve has shrunk into
the joint area and while it is still hot and soft,
run a small hand roller over it to push out any
trapped air.
Pay particular attention to the weld and
cutback area. Reheat areas if necessary.
The sleeve is fully recovered when all of the
following have occurred:
- The sleeve has fully conformed to the pipe
and adjacent coating.
- There are no cold spots or dimples on the
sleeve surface.
- Weld bead profile and other step downs
can be seen through the sleeve.
- Adhesive flow is evident on both edges,
after sleeve is cool.
An 80 mm (3.2”) wide sacrificial sleeve is
installed on the leading edge to function as a
wear cone during pull thru of the pipe.
Start by heating the leading edge area to
70°C (160°F).
Wrap the leading edge sleeve over the
transition DIRAX - mill coating. Make sure
that the closure is placed away from the main
sleeve closure. Preheat the inside adhesive
layer just next to the closure for a few
seconds. Press down to make it stick to the
other sheet end
Heat the closure area and immediately pat it
down with a gloved hand.
Shrink the leading edge sleeve down by
moving the torch all the way around the pipe
in a paintbrush motion. Make sure the sleeve
has fully shrunk and adhesive flow is evident
on both edges.
Smooth down the edges of the sleeve with
the Raychem silicone hand roller.
Sleeve is fully recovered when all
the following have occurred:
- The sleeve has fully conformed to the pipe
and adjacent coating.
- There are no cold spots or dimples on the
sleeve surface.
- Weld bead profile and other step downs
can be seen through the sleeve.
- Adhesive flow is evident on both edges
after sleeve is cool.
Before the DIRAX can be exposed to the soil
forces the joint should be cooled down to
ambient temperature
