Sometimes what’s needed to deliver the best outcomes isn’t just training, skill and cutting-edge technology – it’s pure experience and teamwork.
Such was the case with the recent low-pressure gas escape repair of a 6” off 16” cast iron under pressure damper tee.
PLCS engineers Mark Bailey and Ross Fairley visited the site to assess the repair and take measurements for the preferred solution – a special fabric kit measuring 1.5 metres long with a circumference of 2.2. metres.
Measurements and photos were immediately sent back to the PLCS Technical Office where Manager Mark Perry immediately began designing the kit to completely encase the tee and incorporate the damper plate valve on the branch. That afternoon, three skilled machinists from PLCS’s sewing room worked in tandem to expedite the manufacturing process began cutting and sewing the various elements of the polyurethane-coated nylon mould that was completed and quality approved the same day.
The following morning, less than 24 hours after the initial site visit, two PLCS teams arrived with the kit to install the repair. Grit blasting and descaling was followed by the application of a primer specially developed by PLCS and designed to promote adhesion of the Flexapress Encapsulant to the pipe and fitting, whilst at the same time providing a secondary anti-corrosion barrier.
The effectiveness of the repair depended in part on achieving an equal depth of sealant coverage fitting and this consistency was critical in ensuring the longevity of the seal.
To avoid the weight of quarter of a ton of sealant slumping and distorting the mould, the teams created and fitted a strategically-placed framework of internal and external supports around the repair area.
This is where experience proves so vital, as Mark Perry explained:
For most repairs, however technically demanding, we can rely on set processes and procedures. However, with this kind of repair involving irregular shapes and angles it’s very much a question of relying on the extensive experience, expertise and ‘feel’ of our engineers.
Once the kit supports were in place the mould was filled and pressurized with 144 litres of Flexapress Encapsulant approved by the Gas Networks to meet and exceed the GIS LC8 Part One Specification for the permanent repair of ferrous gas main joints and fittings, with a life seal expectancy of more than 50 years.
Planning and team work were the order of the day to meet the challenge of mixing, pouring and being able to pressurize the encapsulant which had a work life of only 12 – 14 minutes due to the hot weather.
PLCS were able to execute the repair and meet the demands of the Network by working together to measure, manufacture and install the special encapsulation gas repair kit to deliver a positive permanent and cost-effective solution. By undertaking this type of repair, PLCS has added real value to the Network asset while fulfilling the ever-present requirement to maintain a safe and environmentally sound gas supply.
The PLCS repair team: Mark Bailey, Ross Fairley, Mark Cartwright and Chris Darby.
The PLCS machinists: Beverley Poole, Margaret Burns, Marylyn Cooper.