DN-14b Mains jointing (butt fusion) up to and including 355mm - duplicate

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Site conducted
Conducted on
Prepared by
Location
Operative being assessed

General requirements

SGN’s policy is to use only fully automatic Butt fusion equipment. Each pipe will be marked as follows, gas, polymer type i.e. A, S or X and size (i.e. outside diameter) and SDR.

Butt fusion preparation

A suitable location, which should be flat and dry, must be used to carry out the operation.
An appropriate shelter must be used if required (i.e. tent)
All machines must have been regularly serviced and are in good condition.
An appropriate power source must be available with sufficient fuel.
Butt fusion machines are not intrinsically safe and must not be used in a gaseous or potentially gaseous atmosphere. 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 reading are and will remain below 20%LEL. Where circumstances change, you will have to reassess and seek authority to proceed from the Operational manager.

Butt fusion equipment check

There is no damage to the heating plate or its non-stick coating
The hydraulic hoses and connections are in good condition and not leaking.
The electric cables and connections are not damaged.
The frame of the machine is sound and all the guides are secure, in place and not distorted.
Prior to connecting the machine to the power supply the heating plate and trimmer must be checked for cleanliness
Any contamination should be cleaned off with clean water and a bristle brush. The non-stick coating should not be damaged.
The trimming tool may be cleaned using and a lint free cloth or paper towel ensuring all trapped plastic deposits are removed. With the Operational Managers permission aluminium cleaner or scouring powder washed off with clean water may be used to remove any oily deposits
Before attempting to fuse a joint ensure that the generator is the correct voltage and power output. Reference must be made to the manufacturer’s instructions.

Butt fusion operation fully automatic

Once the machine has been confirmed as suitable for use after carrying out the above checks, the machine and its component parts may be connected together.
The following parameters must be set on the Butt fusion machine.
SDR
 Main diameter and type i.e. gas for main to be fused together.
Operator’s code, this will identify who fused the joint together
Job details.

The butt fusion sequence is as follows:

Ensure the pipes to be fused are of the same diameter.
The pipe end must be cleaned inside and out using a clean non-synthetic cloth or paper towelling. Any tarry deposits or writing must be scraped of using an approved scraper for a distance of 25mm. this may have to be increased if a large amount of trimming is required.
Secure the trimmer into the machine.
Ensure the pipe is placed on pipe rollers; place the ends of the pipe to be fused into the machine against the trimmer. If possible, the pipe markings should face upwards.
Attach clamps to hold the pipe in place
To avoid the heater plate becoming chilled due to draughts passing through the pipe, temporary end caps should be installed, in wet and windy conditions a tent erected over the Butt Fusion machine.
Refer to manufacturer’s instructions to operate the “auto trim” cycle and continue the trimming until an even swarf of PE is shaved off both ends of the pipe. At this stage trimming, can be discontinued.
When the machine has pulled the pipe apart remove the trimmer and avoid contact with the trimmed ends, remove the swarf from inside and around the pipe.
Referring to manufacturer’s instructions operate the “check” cycle. A visual check by the Operative is required to confirm misalignment is no greater than 1 mm.
Once the alignment check is complete and the pipe has been separated the heater plate can be installed between the pipes and secured. A check must be made to ensure that the thermostatically controlled heater plate is at the correct temperature. This can be confirmed by ensuring that the heater pointer is in the green quadrant of the heater gauge. Referring to manufactures instructions operate the fusion cycle in which the molten ends of the PE pipes are pulled together under controlled pressure
On completion of the automated fusion cycles, including the cooling time, carefully remove the pipe from the machine.
Question - If this is the first joint of the day or if the heating plate has been washed the heating cycle must be cancelled after the bead up sequence is complete. The machine must then be opened, and the heater plate removed, and the melted pipe allowed to cool. This process must be completed twice on mains above 180mm diameter as this cleans the heater plate. Give three other examples of when this process must be repeated.
Answer - Heater has been switched off and allowed to cool.
A different size pipe is to be used.
A different SDR is to be used.

Quality checks:

The 1st joint (or 1st and 2nd joint on pipe above 180mm) shown on the print out or electronic copy must be a fail at the fusion cycle to indicate that the first joint was a “dummy” joint to clear the heater plate
Check the complete weld bead for evenness.
Check the bead width with a bead gauge and ensure that it is satisfactory
Using an approved external bead remover, remove the external bead and carry out visual checks on the underside of the bead for contamination, a bend back test must be carried out to identify any slits defects and lack of fusion. It is important that all beads and pipe joints are numbered and the beads passed to the Operational manager
Where a bead inspection indicates a faulty joint, the joint must be cut out and the pipe re-jointed using the above procedure. A verbal report must be given to the Operational manager.
A record of all joint(s) must be provided. A potable data printer may be attached to the Butt Fusion machine and a print taken of all the joints. Alternatively, an electronic copy may be downloaded. Reference to the manufacturer’s instructions must be made to operate the printer. Only those printers designed for that make and model of machine may be used.
Ensure that the information collected is collated into the project file folder.