January 2019, Vol. 246, No. 1

Tech Notes

Expanding Pipe Lining Capabilities

Danish pipe lining system Bluelight uses LED curing of the liners for installation. Manufactured by one of the largest lining contractors in Europe, Per Aarsleff Denmark, the system has been in development for about eight years.  

Bluelight liners can be installed and cured around multiple 90° bends within a pipe run and negotiate diameter changes quickly.  

The use of LED lights, which emit a 360° of light without any moving parts, can cure glass-fiber liners, as well as felt liners increases its capabilities and includes the potential for “blind shot” linings with only single-entry points.   

PBF Drainage Services is now the U.K. distributor for Bluelight.


The Bluelight system uses inversion equipment to install liners. The system can keep pressure in the liner where water infiltration occurs by means of an adaptor for the curing system, either directly into the liner or via the inversion equipment.   

A Bluelight liner installation being installed. Photo by PBF Drainage Services

The LED light head is then pushed or pulled through the installed liner to the end point and the LED lights are then switched on using the highly automated touch screen control panel. The control system then records and monitors the settings including pressure, light intensity, curing speed, temperature and it also controls the speed at which the light head is pulled back through the liner.   

The liner is kept up to pressure using a cooled air that is blown down the push rod system attached to the light train and through the middle of the light head which in turn also cools the LED lights. Once the light head is back within a meter of the access point the automatic motor stops, and then the head is pulled back manually to prevent any damage occurring through over-pulling the light head.   

The Bluelight system can use 100-mm to 250-mm (4-inch to 10-inch) diameter inversion liners and up to 600-mm (25-inch) diameter glass-fiber liners.   

The commonly required cable lengths are 40 meters for the small 18-mm diameter light head, 50 meters for the larger 22-mm diameter light head and 100 meters with the 22-mm diameter light head. Curing can also be carried out from both ends of the pipe run to increase installation lengths if required.   

The Bluelight system generally uses pre-wet liners that have a shelf life of about three months. Liners can also be wet-out on site if required, a process requiring no mixing of chemicals – Bluelight uses a single-part resin.   

The liners have been specifically designed for use with the Bluelight system and have undergone full German DIBT certification, which includes strength testing, abrasion testing and the ability to withstand high-pressure jetting. The liners have also undergone continuous testing to make sure that no delamination occurs between the felts and the outer layer.  

With installation similar to traditional inversion lining, training of the PBF crews that will be use the system has mainly involved use of the control system and learning the particulars of the installation process. This training was carried out in Denmark with Per Aarsleff. This also means that now as a distributor PBF will be able to offer the same quality of training to any customers purchasing the system.  


The Bluelight system is primarily used where speed and minimal work area issues are present. This has included in and around hospitals, schools, care homes, as well as road gullies and other outdoor areas.   

As an example, speed was a factor at a local university over the holidays, when a completion had to be reached without fail. On average, 11 liners were installed during each shift, ranging from 5 to 38 meters in length.   

The noise of the equipment is minimal as once inflated the liners are kept at pressure via the light head itself with only a small volume of air required. The equipment can be powered by either 240-volt (v) or 110-v sources and requires a 2.8 kVa generator, which is standard size for many contractors.  

The installation equipment and curing equipment used with Bluelight requires a small footprint. Curing speeds of up to 1.6 meters per minute are possible.   

Because the entire Bluelight process is monitored by an internal camera system, defects can be seen prior to curing and rectified before any problems arise.  P&GJ 

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