Butt Fusion

HPU Unit

Butt fusion is used to accomplish connections of 4” or larger pipes and/or fittings. There are many models of butt fusion machines, each designed for specific pipe size range. Some are light weight for use in overhead installations, other are designed to be used on the ground as part of a pre-fabrication station. To insure you have the proper equipment for the job, please consult with PESTAN support or with an approved PESTAN equipment manufacturer.

There are two main types of butt fusion machines, Manual and Hydraulic (shown in the photo above). The difference in the two is pressure regulation: one uses manual force, the other uses a hydraulic power unit. The basic principles of fusion is the same for both types of fusion machines.

Before performing butt fusion, read the fusion machine manual. Familiarize yourself with the operation of the fusion machine and follow all safety measures and recommendations.

Verify the sizes of the inserts are compatible with the pipe and/or fitting size. Secure the inserts into the machine clamps. Clean the heating plate with lint free, non-synthetic cloth or paper towel.

Plug the fusion machine and heating plate into the power source and verify the temperature of heating plate reached 410°F (210°C), with maximum variance of +/-15°F. Make sure power supply is sufficient for the machine used. Insufficient power supply can cause cold fusions that will fail. If using extension cords, insure that cord is capable of delivering the required power and that you are within a reasonable distance from the power supply.

Cut the pipe to the desired length. Make sure to cut as squarely as possible.

Place pipes and/or fitting into the clamps of the fusion machine, leaving approximately 1” from the edge of the pipe to the clamp. Adjust second clamp of the fusion machine to accommodate length of the pipe/fitting. If there is ovality in the pipe/fitting, place the long side vertically, so the clamps help re-round the pipe.

Butt Fusion Procedure pic 1&2

Note: if two pipes are being fused, line up the print lines on both pipes. If print line is not available, line up the stripes on the pipe.

Insert Facer. Make sure facer is not touching the pipe and/or fitting, turn it on and let it reach full speed.

Slowly increase the pressure control valve until carriage with pipes and/or fittings move towards each other and trim until the jaws come in contact with the facer stops.

Butt Fusion Procedure pic 3&4

Note: if facer motor stalls, decrease the pressure.

When trimming is achieved, drive the carriage away from the facer and then turn the facer off.

Remove facer and place it in the holder.

Clear shavings from the pipes and the fusion space. Clean faced ends of the pipe and/or fitting with the lint free non-synthetic cloth or paper towel.

Inspect shavings ribbons for at least one complete ribbon from both ends. This ensures that the pipe faces are clean and parallel.

7 - Ribbon Check

Slowly increase the pressure until the carriage starts moving, then back the pressure down until the carriage is barely moving. This is your Drag Pressure.

Close the carriage, visually check for the vertical alignment of the faced ends. If needed, tighten the inside clamp on the high side to bring ends into the alignment and re-face the pipe.

8 - Vertical Alligment Check

Note: Pen/marker or other slim flat edged instrument can also be used to check if the ends are vertically aligned.

Once facing is completed and both faced ends are aligned, set the Fusion Pressure to recommended pressures depending on the pipe size, wall thickness and machine model. Fusion Pressures can be found in Pestan Catalog or at our web site. Bring pipe ends together to insure that pipe doesn’t slip in clamps. Open carriage with the space between faced ends with 2-3” gap and insert the heating plate. Bring the faced ends onto the heating plate using the Fusion Pressure.

Butt Fusion Procedure pic 7&8

Watch closely for the formation of the beads where the pipe/fitting touches the heating plate. When a thin line of melt appears all the way around the pipe, drop the pressure down to 0 if the machine has locking carriage, otherwise drop the pressure to Drag pressure and start measuring the required Heating Time.

Wait for the entire Heating Time to elapse (found in Table Butt Fusion Heating and Cooling Times below).

Shift the fusion machine into fusion pressure.

After reaching the proper Heating Time, Open the carriage and carefully remove the heating plate. Quickly (within 3 seconds) inspect heated ends for contamination, concave pipe/fitting face and a consistent melt bead.

After the inspection, use the Fusion Pressure to close the carriage and start the Cooling Time (found in Table Butt Fusion Heating and Cooling Times below).

Butt Fusion Procedure pic 9&10

Leave the fusion machine running for the entire Cooling Time. Depending on the type of fusion machine you may need to periodically check the pressure gauge, and adjust to keep the required Fusion Pressure.

Butt Fusion Procedure pic 11&12

Note: Do not pour water onto the connecting to shorten the Cooling Time. If both ends of the pipes and/or fittings continues to be supported, then Cooling Times can be reduced by 50%.

After reaching Cooling Time, bring pressure to 0 and release pipes and or fittings from the clamps.

Inspect the joint for any contamination, uniform bead size, no double-bead formation.