DN-15f - Branch connections PE

Title Page

Site conducted
Conducted on
Prepared by
Location
Operative being assessed

Tools and equipment

PE UP Branch Drilling Machine
Gas Detection Equipment
Timber Supports
Pressure testing Equipment
Spanners & Torque Wrench
PE Pipe Scrapers and Marker Pens
Clean, Damp, non-synthetic cloth or Paper towels
Under Clamp / Top Loading Too
Appropriate Pilot & Cup Drills
Re-rounding Clamp
Electrofusion Control Unit
Print Control Unit
Leakage Detection Fluid

General requirements

Prior to commencing any work ensure that the following documentation is available and
authorised where appropriate.
1. Job instructions
2. Routine / Non-Routine operation procedures
3. Permit to work

Pipe, fitting & branch saddle preparation:

Confirm mains diameter, SDR and material type and follow the requirements for PE jointing specified within Appendix C (SGN/WI/ML/2)
Depending on the orientation of the branch saddle (horizontal or vertical) sufficient clearance around the pipe and drilling machine must be made see Section A1, (SGN/WI/ML/2) for dimensions
Where the branch saddle is to be installed in the vertical plane, there must be sufficient cover to protect the proposed new main or branch outlet. If this is not possible the Operational Manager must be informed before continuing with the operation.
Confirm the proposed location of the branch saddle will maintain the minimum proximity from other fittings, joints or squeeze-offs and that it is free from damage –i.e. 10% rule.
It is recommended prior to any preparation work being undertaken that the pipe is sufficiently rounded to achieve a good fit. For some type of branch saddles, re-rounding must be used for the installation. These should be fitted and left in position either side of the branch saddle, for a period recommended by the manufacturer.
Using water, thoroughly clean the polythene pipe across the area where the weld is to be made.
Dry the area with a lint free cloth.
Position the branch saddle still in its protective bag or packaging and draw around the base of the fitting plus 25mm with a marker pen.
The branch saddle must be stored in its protective bag until it is ready to be used.
Prepare the pipe surface of PE 80 pipes by scrapping the area thoroughly by using a hand scraper. Care should be taken to avoid gouging or scoring the surface of the pipe if the surface is subsequently contaminated then the whole area should be remarked and scraped
Fit a pressure point as per Section D2, figure 33, (SGN/WI/ML/2), install a pressure gauge on one side of the proposed installation on the parent main to allow the pressure to be monitored throughout the operation. The Routine or Non- Routine Procedure must specify the minimum pressure and the monitoring must check the pressure does not fall below that specified.

Assembly of PE branch saddle:

Depending on the fitting and the diameter of the main the fitting may have an under clamp or top loading tool to generate the pressure required during the welding process.
Remove the branch connection from its protective bag.
Remove the saddle protective base cover.
As the saddle base contains the heating coil, care must be taken not to handle or contaminate
Fit the branch saddle fitting as per manufacturer’s instructions, ensuring that the top load pressure is applied or that the backing strap is tightened to the proper torque settings depending on the type of branch saddle used. Ensuring that the fitting is in correct contact with the pipe surface.
The branch saddle should be adequately supported.
Connect the Electrofusion Control Unit (ECU) to the fitting.
Follow the menu of questions on the ECU and when prompted input the predetermined fusion time according to the fitting label.
Upon completion of the fusion cycle the fitting must be allowed to cool for at least the time marked on the fitting.
Where fitted, check that the fusion indicators have risen.
The under clamp or top loading mechanisms must not be removed until the fitting has cooled for the specified time on the fitting.

Assembly of valve & drilling equipment:

The installed fitting can be integrity tested with or without the drilling machine assembled or connected. If the branch saddle is to be tested without the drilling machines assembled refer to “Procedure D – Pressure testing of fittings and Equipment”, otherwise continue bellow.
Branch saddle – flange outlet. The following must be undertaken. + Check the size and condition of the cutter and that the correct pilot drill is in place if applicable. + Check that the valve is fault operable. If using a gate valve note the number of turns from the fully opened to the full closed position. + Leave the valve in the fully open position + Connect the isolating valve to the flanged outlet of the branch saddle. + Ensure the drilling machine is correctly fitted to the valve and adequately supported. + Ensure all flange bolts are tightened in the correct sequence and to the correct torque. + Pressure test the assembly as described in Procedures in D bellow
- Yes
- No
- N/A

Pressure testing of fittings & equipment:

When pressure testing branch saddles, the test volume is small in comparison to testing pipes. Field experience has shown that pressure can fluctuate by up to 25mbr due to temperature and creep effects.
The pressure test can be undertaken with or without the drilling machine connected. Where the drilling machine is to be connected carry out the items listed in E.a. below before continuing.
The full number of appropriate studs or bolts provided for blanking flanges must always be used. Any studs or bolts with worn or damaged threads must be replaced
- Yes
- No
- N/A
Safety precautions: + The Operative must ensure that all personnel engaged on testing work, or any other work associated with testing, are aware of the possible consequences of the fitting failing under pressure conditions. A site-specific hazard assessment must be completed.
Precautions must be taken to ensure mobile phones; radios, etc. are not operated in the vicinity of digital test instruments, as the pressure indication might become erratic.
All fittings and associated equipment must be restrained and supported against movement during the test.
The Operative must ensure all necessary precautions are taken: + Before pressurisation; + During pressurisation; + During pressurisation and before dismantling the equipment; + After depressurisation and during dismantling the equipment.
Warning notices that testing is in progress should be prominently displayed near the excavation
Before pressurisation begins a final check must be made to ensure that the test section is secure.
Whilst the pressure is being raised no unauthorised persons must enter the area or interfere with the pipe work
Pressure test procedure: + The valve if part of installation must be left in the open position. + Air should be introduced under controlled conditions into the fitting through apparatus attached to the branch saddle or the drilling machine attachment. + The pressure in the installation should be increased to 350mbr for LP main and 3.0bar for MP mains. On MP mains, the air should be introduced in 0.5 bar increments. + The connection to the branch saddle or drilling machine must be isolated and stabilisation period in accordance with Section G5, (SGN/WI/ML/2). + The test period duration and a presentable pressure drop must be in accordance with Table 45, (SGN/WI/ML/2) + The fitting must be visually checked for leakage using an approved leak detection fluid. + Wash fitting thoroughly with clean water after using leak detection fluid.
Let by valve test: + A let by test must be conducted following a pressure test. Close the valve and release the pressure between the valve and the test flange in a controlled manner + Ensure the gauge is reading zero and monitor the pressure for 1 minute. There must be no increase in pressure on the gauge. + If there is an increase in pressure on the gauge then the valve is passing. The vent must be opened and shut to check there is no debris in the valve housing and the let by test must be repeated. Further investigation on the valve housing must be made, where necessary. + If the valve cannot hold a 'let by test' then the valve must be replaced with another valve and pressure tested in accordance with D.k. above and the 'let by test' undertaken on the new valve. + On completion of a successful pressure and let by test, release the pressure in a controlled manner. + Recheck the valve open and closes properly + A test certificate must be completed and signed on completion of successful test. + Remove the test apparatus and secure the branch saddle outlet by fully closing the valve and seal by using a blank flange or begin the drilling operation as appropriate. On medium pressure mains, the blank flange must incorporate a pressure relief facility.
Inconclusive pressure test: + If the pressure loss is in access of the allowable maximum during the duration of the test and no leakage is visually detected, the test must be repeated with extended test duration of 30 minutes. The pressure drop must not exceed 25mbr.
Failed pressure test: + If leakage is detected from the installed fitting, then the fitting must not be used DO NOT REHEAT THE FITTING. The fitting must be left in place and cut near the base of the branch saddle to prevent any future connection being made onto the fitting. If the leakage is evident from another source i.e. flanges or drilling machine, then this must be rectified, and another pressure test undertaken

Drilling operation

The following drilling equipment check must be undertaken: + Ensure that the drilling machine is fit for purpose for the correct pressure rating. + Ensure the drilling machine is securely supported. + Ensure that the correct diameter of PE cup drill is used, it is in good condition and that it will pass through the valve and saddle without causing damage. + Ensure that all drilling equipment is in satisfactory condition. + Ensure that any ancillary equipment is in satisfactory condition i.e. the correct pilot drill is used, where applicable. + The travel of the drill must be measured and marked to ensure that it is of adequate length to drill the front wall of the main without cutting into the rear wall (refer to Figure 32, (SGN/WI/ML/2) for drilling measurements through valve arrangement) and complete Table 19, (SGN/WI/ML/2)
Advance drill until pilot drill touches the main
Mark dimension (D less B) on stay bar of the drilling machine with chalk.
Measure and mark dimension 'C'.
Measure and mark dimension 'X'.
Branch saddle drilling

Removal of drilling machine

When the main has been drilled, retract the drill
Close the valve and release the pressure between the valve and the drilling machine to zero.
- Yes
- No
- N/A
The pressure gauge must be monitored for one minute. There must be no increase in pressure on the gauge.
Remove the drilling machine
Either fit a blank flange or connect the main to the valve.
On MP mains, the blank flange must incorporate a pressure relief facility.
Remove coupon from the drill and pass to Operational Manager
Test for leaks around the final connection using an n approved leak detection fluid.
Clean and store equipment
Under no gas conditions remove the test point, plug off and test with leak detection fluid.
Remove any wooden supports from bellow the UPT installed as part of operations by supporting with fine fill material.
Apply anti corrosion tape to under the pressure tee, valve and bolts ensuring a 55% overlap. Care must be taken applying the tape around the valve and bolts where moulding to shape must be taken