A NOT-SO-TYPICAL PROJECT FOR A SOUTHEAST DEVON CONTRACTOR

For over 20 years Ken Twydell has owned and operated a small, local drainage repair company, Draincure from offices in Paignton, Devon, covering a 30-mile working radius.

The company works generally on domestic projects and emergency works, such as blockage clearance, cleaning and survey works, with the company’s works being primarily in the 4 ” (100 mm) and 6 ” (150 mm) diameter pipe range, although other diameters are possible. The company’s client list includes everything from individual house owners and local surveyors seeking drainage reports, through Housing Associations and local councils to local and national property letting agencies, some in the very high value end of the market. Some eight years ago, Ken was joined in the business by his wife Julie who returned to work after raising the couple’s children.

Since 2001, Draincure introduced lining technology to its portfolio using proprietary, off-the-shelf systems. In 2002, after using various resins and material for its full length lining, patch and ‘blind shot’ lining works, both Ken and Julie, found they disliked the smell of styrene and had other product issues. They went to the market place to see what systems were available to them that would reduce if not eliminated these concerns. After some time researching the available products, the Twydells were introduced to the Brawoliner System by John Kelly of Peterborough-based CJ Kelly Associates. John is the UK consultant for KOB and MC-Building Chemicals for lining works and projects. After a trip to Germany to see the system in production and operation Ken and Julie were convinced this was the system they were looking for. Draincure now uses Brawoliner exclusively on its manhole-to-manhole lining works.

TORQUAY PROJECT

A recent project carried by Draincure highlights some of the advantages of the Brawoliner system. The job involved descaling and lining a short length of cast iron pipe, with a bend, running under buildings situated by Torquay harbour. Brawoliner is particularly suited to lining cast iron pipe as there is no shrinkage and the liner can bond to the pipe. 

The biggest problem on this project was access. Top access was in a manhole situated in a small, enclosed yard measuring approximately 1 m by 2.5 m. To make matters worse there was both a soil and a waste pipe running horizontally 4” above the manhole. Access to the yard was through a removable panel covering an old window opening that was partially obscured by a new built-in seating unit in a night club/cafe bar. Whilst this was difficult, it was an improvement on the previous situation where a fish tank had been built into the old window opening, which meant the only remaining access was through an upstairs window and down a ladder!

The lower manhole contained a sealed, cast iron fitting (Burns box) and was situated under a carpet on the sales floor of a designer clothes shop next door. The stock of the shop was very expensive - some of the garments costing over £1000 - so any tainting had to be avoided. The resin used with Brawoliner was ideal for this as no volatile solvents are used.

The timing available to complete the work was problematic to say the least. The shop kept normal 9 to 5 hours Monday to Saturday, whilst the cafe bar was open all day at weekends and every night until 3.00 a.m. except Sundays when it closed at 12.30 a.m. Neither establishment would agree to close for any length of time, which left Sunday night as the only time when a reasonable working period would be available.

In order to save time ‘on the night’, most of the descaling was carried out in ‘normal’ time during the week from the cafe bar end. Due to the situation of the manholes, the use of high pressure water jetting was not possible so Ken and Julie used a Ridge K1500 sectional spring machine with a chain knocker. This did an excellent job and, apart from removing the build up of years of rust, it also dislodged a 5” coach bolt and a 4” drain plunger disc.

Access and security for the Sunday night operation had been arranged by the property landlord. As the lining part of the work was arranged for an overnight operation and the stock of the shop was so valuable, a security guard was engaged.

On the night, the first task of the night was to carry out a final clearance and descaling of the drain followed by a CCTV survey during which the distance between the manholes was established. The Brawoliner was cut to length, impregnated with resin and wound into the inversion drum. Using air pressure, it was then inverted into the drain; going upstream from the manhole in the shop, as that afforded the easiest access. When the liner reached the upper manhole, Ken guided it into a short length of spare calibration hose in order to minimise mess and protect the end of the liner. The air was then replaced by hot water, which was circulated for an hour to accelerate the curing process. The epoxy resin used is thermoplastic – that is, it gets soft at higher temperatures - so the hot water was then replaced with cold water in order to bring the resin down to ambient temperatures.

There only remained the trimming of the liner to complete the job. Usually this would be carried out with a grinder but the dust and mess that this makes would have been unacceptable in the shop. So a hot air gun was used to soften the thermoplastic epoxy resin before being able to trim it with a Stanley knife. The job was finished on schedule without disruption to either business.

 

UNDERSTANDING THE PROBLEM

Draincure has always aimed at producing a solution for its clients that is easy for a layman to understand. To this end, the company has developed its own style of drainage survey reporting, which relies on the use of layman’s terms to ensure clarity of the report to the client. The use of National Standard Coding for fault recognition is put aside with preference being given to description of a fault in full yet simple to understand terms. Printed, reports with scale diagrams are also created post survey to make understanding easier.

Although excavation techniques are an option, Draincure prefers to operate wherever possible in the most non-disruptive way and achieves this by using a variety of trenchless techniques including full manhole-to-manhole lining with Brawoliner, localised patch repairs and re-rounding technology as well as selection of CCTV systems.

The Brawoliner system uses a seamless lining textile fabric that is applicable to pipes from 75 to 255 mm diameter, with wrinkle free installation around 90o bends. Draincure generally utilises compressed-air inversion from an inversion drum with either ambient or hot water curing.

The Brawoliner system is designed to answer some of the more pressing environmental problems found with more established lining system resins across Europe, and does this by using environmentally friendly resins. Brawoliner has also been presented with an award for innovation in the Rhineland-Palatinate region of Germany on the basis that it was specially designed to meet the latest environmental standards, as well as being manufactured to ISO9002 standard.

Another option used by Draincure is the localised patch repair for which Draincure buys-in lining materials in bulk and, again with MC-Building Chemicals resins, prepares and installs it own patch repairs.

As well as the lining and patch systems Draincure also has the ability to re-round pitch fibre pipes when necessary using the Tolverth-manufactured re-rounding system.