THE NEOFIT PRINCIPLE
The principle consists of inserting a thin tube made of Polyethylene Terephthalate (PET), into the lead pipe. This thermoplastic material known as PET is tough and flexible and allows easy insertion into the host pipe. The small diameter tube is then inflated and expands until it reaches the inner wall of the old pipe. It is this thin wall liner that is impermeable for lead to pass and reach the drinking water inside the relined pipe.
The installation steps are:
The water pressure has to be taken of and then the pipe has to be disconnected at the water main and the water meter or other connection point in the house.
In this step air, is blown through the lead pipe to remove the remaining water and the sediments which may be present in the lead pipe. Lead pipes do in general not develop hard encrustation, so in most cases mechanical cleaning is not needed, other than using a brush when there is some sediment at the inside which cannot be blown away.
In this step, the small diameter NEOFIT liner is pushed or pulled into the host pipe. To this end it might be
necessary to have a line inside to the host pipe to be able to pull the liner through the host pipe. This line can be brought when blowing air through the pipe. The fact that the NEOFIT liner is rather flexible before it is expanded helps a lot to come around bends etc.
After the liner is brought into the host pipe, the liner has to be connected to a PLC driven piece of equipment that regulates the heating of the liner by flushing hot water though it and that starts to expand the pipe and cool it down afterwards.
The lead pipe, the connection between the coupler and the lead and the connector itself is lined with a seamless NEOFIT t liner. (See picture).
Then finally the lined host pipe can be reconnected to the water meter or other connection point in the house and to the water main. Re connection is done in such a way that no water can get in touch with the lead pipe and cannot penetrate between the liner and host pipe.
In practice this process goes very quick and easy and does not require a lot of preparation and time to achieve the solution. Depending on the layout at the site, the length of the host pipe etc, the renovations lasts between 1 and 3 hours.
In general the time that the customer is disconnected from the water main is not more than 45 minutes to 1 hour. This is an important aspect, because customers are getting more demanding and do not like that they can not flush the toilet, take a shower or fix a pot of tea for much more then 1 or 2 hours. The other issue that is very important for most customers is that their garden and pavement around the house does not require to be opened. In most cases the renovation can be done from the public area, where the water main is situated.
WATER QUALITY AND APPROVALS
The lining material of the liner consists of Polyethylene Terephthalate (PET), the same material as from which bottles for water and refreshments are made of. It is therefore one of the best materials to be used for this kind of applications. Meanwhile several institutes and water associations have approved the NEOFIT system for use with potable water. The Netherlands Waterworks testing and research institute KIWA has approved the liner in 1995. On all aspects, NEOFIT passed the requirements easily.
NEOFIT holds approvals from several national authorities such as the French LHRSP, Nancy, the Belgian Belgacqua, the Dutch KIWA, Australian WSAA and NSF/ANSI 61 in the US for drinking water applications.
In general NEOFIT is applied as a liner depending on the existing pipe for its structural support. Consequently, in general, the PET pipe after expansion is to be considered as a liner which interacts with the existing pipe in this respect: an interactive pressure pipe liner.
An unsupported, expanded NEOFIT pipe with dimensions 12 mm x 0,2 mm, on its own (without support of the existing pipe) can resist an internal pressure of 8 bar for 50 years. The strength is comparable to that of a PVC or PE service pipe.
The existing pipe is needed however, to provide stiffness. The lining would collapse under external loading when not supported.
Great advantage is that the lining does have the capability to span gaps, e.g. caused by pit corrosion.
The expanded pipe can withstand an internal pressures of at least 25 bar. This has been thoroughly analysed in simulated host pipes with holes, 2/3 x internal diameter of host pipe (e.g. a hole of 30 mm in a 45 ID pipe).
QUALITY ASPECTS RELATED TO RENOVATION
Good working procedures, quality control of liners and workmanship is important to ensure that the customers gets a professional and sustainable solution for their problem with leaking or corroding of water supply pipes.
NEOFIT liner this level is considered "Medium" as it does not involve chemical alterations during installation, but it requires a step with heating and cooling. NEOFIT is operated in a closed quality circle. The NEOFIT pipe is tested during the production run and afterwards to ensure the ability to perform well during installation. The installation procedure is highly automated by using PLC's in the installation equipment