Reading Through Coatings: 3LPE & 3LPP

Modern 3-Layer Polyethylene/Polypropylene (3LPE/3LPP) coatings are capable of withstanding a wide variety of temperatures and environments and as a result 3LPE and 3LPP are very much an industry standard coating for buried line that is carrying oil and gas.
The 3LPE/3LPP coating is a multilayer coating composed of three distinct, layered components:

  • A fusion bonded epoxy layer
  • A copolymer adhesive layer
  • A polypropylene or polyethylene layer.

The complex nature of the layered coating has huge benefits for protecting the external walls of the pipe but these layers can make it harder for simple, regular inspection of the internal wall – where, corrosion and erosion on some level will be taking place out of sight.

All of Cygnus’ MK5 ultrasonic thickness gauges (UTG) use our S2C probes; a combination which enables our equipment to penetrate through up to 0.4 inch (20mm) of coating. There is no need to remove or damage any aspect of the 3LPE / 3LPP coating. Simply place the S2C probe on to the coating, and the gauge will only measure the steel underneath.

This simplicity of use and convenience also inheres in the Cygnus 1 Ex UT gauge – the world’s only thickness meter that is certified to ATEX, IECEx, UKEX for Zone 0 and NRTL for Class 1, Division 1 for use in potentially explosive atmospheres.

As well as a core focus on simplicity of use and convenience, the Cygnus MK5 thickness gauges are also versatile and feature-rich. Our PLUS models come equipped with rectified Ascan (waveform) functionality; these Ascans can be read live on site or can be stored (logged) alongside a thickness reading for review at a later date – as a part of a predictive maintenance programme.

Having been in the game for 40 years, Cygnus genuinely knows and understands that these are tools that will lead a rough life; so Cygnus gauges are also highly ruggedized. The whole MK5 range of units are all tested to Mil Spec 810G – drop proof, shock proof, water and dust tight (IP67).

A full range of single and dual element probes are also available for a host of other applications.