DN-14a Mains jointing (electrofusion) up to and including 355mm

Title Page

Site conducted
Conducted on
Prepared by
Location
Operative being assessed

Tools and equipment

PE pipe and cutters
Electrofusion control unit and power source
Top loading clamp
Restraining clamp
Coupler clamp (as required)
Scraper & marker pens
Print control unit
Tent / cover

General requirements: Each fitting will be marked as follows:

Size (i.e. outside diameter) and SDR
Fusion heating times and for longer fitting, the power requirements
Cooling time
Question = Electrofusion must not be used if the Operative suspects that a gaseous atmosphere exists. This must be checked using an approved gas detector at the start and during the operation to confirm that gas readings are, and will remain below what level of gas readings?
Answer - 20% LEL, do not take the Electrofusion control box into the excavation or a gaseous atmosphere
A suitable location that should be flat and dry must be used to carry out the operation.
If there is likely to be a problem with contamination due to air borne dust or wind chill, an appropriate shelter around the machine must be used.
ALWAYS use the correct size of Electrofusion saddle and couplers on PE mains.
Ensure that fittings remain in their protective bag until immediately prior to use.
DO NOT scrape any surface containing a heating element
Should the Fusion stop in mid process, allow the fitting and pipe to cool down, cut off/out the fitting and start again. DO NOT ATTEMPT TO RE-FUSE ANY FITTTINGS.
Cut pipe ends square and adequately scrape for successful fusion
Ensure all personnel are aware that Electrofusion is in progress and they do nothing to disrupt the procedure.
PE pipe must be checked for ovality prior to fusing and a re-rounding tool should be used where necessary.
Prior to commencing the Electrofusion process, confirm that the voltage of the fusion box is compatible with the fitting i.e. 39.5, 48 or 80 volts and the generator is the correct voltage / power output. Ensure that the generator has sufficient fuel to complete the Electrofusion cycle.
For separation distances between fittings /squeeze-offs reference must be made to Appendix B (SGN/WI/SL/1)

Electrofusion coupler preparation:

Prepare suitable restraining clamp for use. Fit adapter shells if required.
Ensure there is sufficient clearance around the main to fit the restraining clamp
Clean the jointing area of the pipe with a clean, damp non-synthetic cloth or paper towelling. If using soapy water this must be cleaned off with water and the joint area dried.
With the fitting, still in the protective bag, place the fitting onto the pipe and, with a marker pen, roughly mark a spiral around the main. The length to be scrapped must be at least half the coupler length plus 25mm. this is the area to be scrapped. Repeat on the second pipe to be joined.
Using an approved scraping tool thoroughly scrape the whole area outlined. If the joint is not made immediately protect the newly scraped surface from contamination.
Care must be taken not to handle or contaminate the surface of the fitting containing the heating coil or section of scraped pipe.
Place the fitting over the scraped area of main, ensuring the main touches the centralstop register in the coupler. Mark the penetration depth on the side of the pipe at either end of the coupler. This provides a visual warning if the fitting moves in relation to the mark prior to fusion taking place.
If the coupler(s) to be installed are for a cut out section to be inserted the section to be pieced in must be scrapped for the full length of the two couplers plus 25mm. the centralstop register must then be knocked out and the two-coupler pushed fully into the new scraped section of PE pipe. Once the section has been placed in the cut-out area the couplers are pulled back over the prepared existing pipe and the restraining clamp.
Assemble the restraining clamp on the main.
Check the penetration. You should be able to move the coupler along the pipe
When the clamp is in place visually check pipe alignment in all planes. Rotate the fitting to ensure no excessive forces are present

Electrofusion coupler process:

To avoid the fitting becoming chilled due to draughts passing through the inside of the pipe, temporary end caps must be installed, and in wet or windy conditions a tent erected over the Fusion area
Start the generator and connect the control leads to the generator
Connect the terminal leads from the control box to the Electrofusion coupler.
For manual fittings, set the control box timer to the fusion time marked on the fitting and press start
For automatic fittings, check the time fitting corresponds with the time on the box.
Stand clear of the fitting when fusion is in progress. Do not adjust the restraining clamp during the fusion progress.
When the control box indicates that fusion is complete, check the fusion indicators, where applicable, have risen.
Disconnect the terminal leads from the fitting; allow the joint to cool for the required cooling time prior to removing the restraining clamp.

Quality checks:

Check that fusion indicators have risen and that no melted material or wire has extruded from the ends of the fitting.
Check that the pipe has not moved during welding, fusion / cooling time.
Check for cleanliness around the joint.
Check for evidence of scraping
If a print facility is available, print out from the Electrofusion control unit and check the result