Welcome to the complete breakdown of everything you need, including knowledge, processes, equipment and tools, to get your fusion job done right.
High-Density Polyethylene (HDPE) pipes are best known for their durability, flexibility and chemical resistance. Whether they are used in water distribution, gas transportation, mining operations or industrial applications, HDPE pipes are essential. To ensure their perfection, quality butt fusion is needed.
Butt fusion connects HDPE pipes together to create a completely seamless, joint. In this short guide, Sandale is going to tackle the practice with step-by-step instructions to do butt fusion correctly.
Sandale’s Butt Fusion Procedures
The following is a breakdown of key steps you will need to complete to successfully complete fuse two HDPE pipes together.
Clean, Install and Clamp the HDPE Pipe
First, you want to clean the pipe to remove any contamination.
Move the pipe in line with the fusion machine’s centre line.
Clamp the pipe to prevent slippage and re-round the pipe. Keep in mind that the outer clamps are for holding the pipe and the inner jaws are for aligning the pipe ends. This will add enough pressure to secure the pipe in place.
Face the Pipe
Face the pipe to remove any oxidization and/or contamination on the pipe ends.
Do this until the facer bottoms out on the stops and is locked between the jaws to establish clean, parallel mating surfaces for the heating operation. Control with minimal pressure to shave ribbons of material from the pipe ends.
Turn the facer off when you’re done, then remove the facer.
Remove the shavings of material.
Align the Pipe
At facing pressure, bring the pipe ends together and check alignment. (Allowable misalignment is up to 10% of the wall thickness).
Adjust alignment by tightening the high side down.
If adjustments are made the facing procedure must be repeated.
Check for Gaps Where the Pipes Join
At facing pressure, check for gaps after the pipe ends made contact.
No detectable gaps are allowed.
Measure Drag on the Pipe
Measure the drag using the proper procedure. This is the force required to overcome the sliding frictional drag created by the machine and pipe.
Keep in mind that your drag will vary according to the length of the pipe, job site conditions, pipe support, etc.
Set Fusion Pressure
Add drag to theoretical pressure and set fusion pressure.
Ensure the pipe does not slip through the jaws at fusion pressure.
Prepare to Add Heat to the HDPE Pipes
Set your equipment’s heater to the proper temperature (400–450℉)
Check the heater surface temperature with a pyrometer for accurate temperature measurement.
Clean the heater butt plates with a clean, non-synthetic cloth.
Remember that the thermometer on the heater shows internal temperature only, not the actual plate temperature.
Heat Bead-Up
Position the heater between pipe ends, but not in contact.
If you are using McElroy’s DataLogger, start the software and set your parameters.
On 14” OD pipe and above, conduct a bead-up cycle.
Below 14” OD pipe briefly ensure contact.
Bead up may need to be done on smaller OD depending on different circumstances.
Shift Sequence
The Shift Sequence relieves the fusion pressure in the cylinders so that the pipe is allowed to soak without force being applied against the heater.
Always shift the selector valve to the ‘Heating’ position then wait for pressure to bleed down to drag pressure.
In most conditions, the directional valve will be shifted to neutral once drag pressure is observed.
Heat-Soak the HDPE Pipes
Ensure full contact with the pipes. On 14” OD and above, conduct a bead-up cycle observing a slight indication of melt around the circumference of the pipe. Then proceed to the shift sequence.
Maintain contact with the heater for the minimum soak time, 4.5 minutes per inch of wall thickness, then check for the minimum bead size.
Fuse the Pipes
After the proper melt bead is formed, shift the selection valve to fusion, open the carriage and dislodge the heater from the pipe ends.
Quickly remove the heater, check the heated pipe ends for contamination, and ensure that the surfaces are not concave.
Close the carriage to apply the pre-set fusion pressure.
Cool the Pipe
Maintain fusion pressure on the joint for at least 11 minutes per inch of the pipe wall thickness.
Additional cooling time may be necessary when fusing in ambient temperatures of 37* C and higher.
Inspect the Fused Pipe
After the cooling cycle is completed and the DataLogger is stopped, shift the carriage control valve to neutral.
Loosen the clamps.
Open the carriage fully to the operators right before opening the jaws for pipe inspection.
Examine the joint.
The bead should be uniform and symmetrical all the way around the pipe.
The valley should not extend down to the pipe surface.
There must be no visible contamination.
View the DataLogger report if available.
If you are more of a visual learner, check out McElroy University’s short video on butt fusion with a TracStar 500 Series 3 Fusion Machine here:
Trust the McElroy DataLogger
Remembering all of these steps and getting the pressure data you need after installation is a full-time job. Fortunately, Sandale uses the McElroy DataLogger, a software system that guides you through the basic fusion process. It makes life easier with helpful tips, and access to a live pressure reading in an easy-to-read chart.
What Does the DataLogger Do?
It records the fusion process on nearly all McElroy fusion machines.
It archives essential details related to the fusion operation and job site.
It lessens the time spent during the fusion joint’s cooling cycle.
It performs a real-time analysis that allows for monitoring of the joint integrity during the fusion process.
The latest version incorporates new standards, including ASTM F3124, which governs the collection of data from plastic pipe fusions.
You can read more about the Datalogger here.
Sandale Provides Advanced Pipe Fusion Training Through McElroy University
Sandale’s team is highly trained in McElroy fusion equipment and is licensed to provide McElroy University training to your team. Designed for operators, technicians, inspectors and engineers, every class will introduce concepts and simulate experiences that your team members will encounter on a pipe fusion jobsite.
Learn more about our fusion training program, then reach out to us for more information on training essentials and upcoming classes.