Abstract: A method of creating a weld between a liner of a section of lined pipe and an electrofusion fitting. The fitting comprises at least one heating element, which is suitably disposed on or in an outer surface of the electrofusion fitting and is electrically isolated from an inner surface of the fitting. The method comprises locating an end of the electrofusion fitting within an end of the section of lined pipe, locating an induction coil within a bore of the electrofusion fitting in the vicinity of the at least one heating element, and supplying electrical power to the induction coil to energise the at least one heating element by electromagnetic induction.

Abstract: An integrity monitoring system for a lined pipeline is provided for monitoring the integrity of a polymer liner in a host pipe. Methods and apparatus are described by which a lined pipeline is provided with such an integrity monitoring system. Sensor cable is able to bridge a joint between sections at lined pipe, for example by routing the sensor cable across the joint via a channel in an electrofusion fitting or by connecting successive lengths of sensor cable via pass-throughs in an electrofusion fitting. Advantageously, the sensor cable is disposed within a continuous annulus between linings and host pipes, and the continuous annulus is maintained across pipe joints using electrofusion fittings.

Abstract: In order to reduce or remove the potential risk of heat damage in the absence of cooling jackets when joining lined pipe sections, each lined pipe section is provided with an insulatory sleeve which is disposed between the host pipe and the respective liner. The sleeves provide discrete thermal protection to the ends of the liners and, where applicable, electrofusion welds between an electrofusion fitting and the liners. The sleeves are first located in the ends of the host pipes which are then lined by drawing the liners through the host pipes via a reduction die to reduce their external diameter. The liners are then reverted towards their original dimensions resulting in a tight fitting against the internal surface of the host pipes and of the insulatory sleeves thereby compressing the insulation material.

Abstract: The invention provides improvements to electrofusion fitting methods that allow for continuity and repeatability of welds between an electrofusion fitting and a pipe lining (or stand-alone pipe). An electrofusion fitting for joining sections of lined pipe has heating elements configured to create at least one weld between the electrofusion fitting and a pipe lining. However, prior to the weld step taking place the electrofusion fitting is heated and expands accordingly to ensure contact with the pipe lining. Preheating the electrofusion fitting also provides a predetermined starting temperature for the fitting and the lining which results in improved fusion cycle reliability. Furthermore, the need for clamps or support frames to support the electrofusion fitting in situ is removed, with corresponding reductions in cycle times, complexity, and hence cost.

Abstract: Methods and apparatus enable the integrity of a liner pipe to be quickly and effectively tested in the field, while permitting rapid removal and replacement of the liner pipe if it is compromised. The liner pipe is leak tested prior to reversion, after being pulled through a host pipe to be lined via a swaging die and while the liner pipe is still under tension. If the liner pipe exhibits a leak, it can be removed from the liner pipe immediately and, importantly, before it has expanded to contact the host pipe. Leak testing apparatus includes a packer, which seals the opposite end of the liner pipe from the end which is pulled, creating a contained fluid volume upon which the leak test is performed. The leak test may be a pressure test or a vacuum test or any other suitable test.

Abstract: A method lays lined pipeline which actively and successfully removes air pockets which might be trapped in the annulus between the liner and the host pipe by progressively flooding the lined pipeline. Further, the liner is brought into closer contact and engagement with the host pipe. The removal of air in the annulus enables the pipeline test pressure to stabilize more quickly and avoids the risk of potential collapse during operational service life in the event the pipeline pressures fluctuate or a vacuum is created during an emergency shutdown.

Abstract: The invention provides improvements to electrofusion fitting methods that allow for continuity and repeatability of welds between an electrofusion fitting and a pipe lining (or stand-alone pipe). An electrofusion fitting for joining sections of lined pipe has heating elements configured to create at least one weld between the electrofusion fitting and a pipe lining, however prior to the weld step taking place the electrofusion fitting is heated and expands accordingly to ensure contact with the pipe lining. Preheating the electrofusion fitting also provides a predetermined starting temperature for the fitting and the lining which results in improved fusion cycle reliability. Furthermore, the need for clamps or support frames to support the electrofusion fitting in situ is removed, with corresponding reductions in cycle times, complexity, and hence cost.

Abstract: Improvements to electrofusion fittings that enable the integrity of a weld between an electrofusion fitting and a pipe lining (or stand-alone pipe) to be tested in the field, and corresponding methods of installation and testing. An electrofusion fitting for joining sections of lined pipe has heating elements configured to create at least one weld between the electrofusion fitting and a pipe lining, and a channel provides fluid access to a test region between the electrofusion fitting and the pipe lining to allow leak testing to be performed. The channel may be provided through the fitting itself, or alternatively through the pipe lining. Methods of fabricating or laying pipeline may incorporate use of the improved fitting whether using length-by-length construction methods or joining subsequent reel-laid or towed-in pipe lengths.

Abstract: An electrofusion fitting includes a tubular length of thermoplastic material, of an outer diameter commensurate with the inner diameter of the ends of a compatible thermoplastic material lining of adjacent lengths of metal pipe, there being at each end of the fitting at least two heater coils on or in close proximity to the outer surface of the fitting, electrical leads from the heater coils extending through the fitting to emerge at the inner surface of the tubular length, for connection to a source of electrical power.