DN-11 Serviflex

Operative being assessed

Ensures excavation is at point of mains connection or garden connection but no closer than 2 metres to the building and is approximately 1 metre long in accordance with Service laying procedure

Traces line of service accurately to check its suitability for using the technique

Visually checks that the service pipe is reasonably sound with no severe corrosion and the service riser is physically sound. Consults the team manager for further advice, if required

Ensures pipe diameter is 1in or 1 1/iin

Checks approximate length of service pipe from meter point to the garden excavation to ensure it is less than 12 metres

Cuts out section of live gas service pipe in accordance with Service laying procedure, if required

Selects compatible Serviflex fittings for pipework size

Closes ECV and disconnects meter and applies electrical bonding requirement, if necessary in accordance with the current SGN procedure

Removes ECV and deburrs steel pipe in house, fits union bend and launch tube

Deburrs steel pipe in garden

Fits the stopper to the spring and applies silicone lubricant

Inserts and probes service from inside the house to identify the number of elbows / bends

Fits elbow wire brush to the end of the spring and cleans the service if required. NB. Only needed if substantial debris is suspected within the service and reinserts the probe

Attaches string line / rope to the brass towing eye and marks the length of the service on the spring

Retracts the string / rop and detaches brass towing eye from spring

Checks that the inserted length is compatible with the estimated length

Question - What action needs to be taken if the inserted length is not compatible with the estimated length and name the possible reasons?

Measures and marks Serviflex and adds 2 metres to measured length and cuts Serviflex pipe to length

Attaches tension gun to Serviflex

Fits gripper over pipe at opposite end and inserts the spring into the Serviflex pipe. (Through gun with <br>female end to nose cone)

Attaches brass towing eye to the end of the spring

Pushes the spring and towing head until the brass head locates in the end of the Serviflex pipe

Positions wire tie wrap in end convolution and tightens with the supplied too

Twists the tie wrap to secure, cuts the tie wrap approximately 6mm (1/4in) and folds flat with Serviflex <br>to ensure it does not foul insertion process

Coils up piping and spring

Ties string line / rope to towing eye and greases nose cone with silicone grease

Instructs team mate to take up slack on string line / rope from outside and inserts nose cone into <br>launch body

Pushes by hand whilst team mate guides the string line / rope until resistance occurs then uses pusher <br>gripper to feed remaining distance until approximately 1 metre left from the top of the service

Checks pipe is fully inserted into the excavation pit and protrudes 1 metre past the end of the steel pipe

Checks condition of pipework to ensure sufficient pipework is in good condition, approx. 300mm to <br>make the garden connections

Releases tension on the gun / spring, removes tension gun and removes towing head

Question - Why is it important to carefully remove the tie wrap?

Lifts tail untwisting wire with wire cutter and applies slight pressure to the spring to aid removal

Removes tension gun, gripper and spring

Removes test ends, removes launch tube bend and union fitting

Fits service head adaptor as per manufacturer’s instructions

Fits garden fitting as per manufacturer’s instructions with injection port uppermost

Fits IECV ensuring no rotation of service head adaptor

Rods the service to check for no constrictions

Selects correct sealant and attaches installation gun to garden fitting as per manufacturer’s instructions

Tightens one of the service head adaptor bleed nuts and slackens the other until hand tight giving a <br>slight sideways movement on the nut

Injects sealant from the garden fitting using only non-expanding sealants to fill the annular space to <br>provide a fire check and not a gas sea

Pumps sealant into steel service until liquid is observed at the service head adaptor vent port then <br>tightens

Maintains pressure on sealant gun for 5 minutes then removes gun as per manufacturer’s instructions <br>by tie wrapping or clipping the sachet feed tube

Rods the service for the final time to check for no constrictions during the sealing process

Finishes commissioning the service in line with current SGN procedures

Disposes of all waste materials in line with current SGN procedures

Completes appropriate documentation to record full service details

Pass assessment or refer for additional training