3LPE coating-features

3LPE coating and its features

3LPE coating

3LPE Coating stands for the three-layer polyethylene coating of the metal. 3LPE coating is most of the users in the pipeline coatings. 3LPE Coating is a multi-layer coating that is composed of three functional components, where Epoxy use as a primer coating of the base metal, and the middle layer is a Polymer adhesive that uses as a secondary primer and polyethylene, is the last layer of the coating. 3LPE coating has a very high mechanical and chemical property that withstands the share tear and wear. Where Epoxy has an excellent chemical and mechanical Corrosion resistance and Polymer is an adhesive material that has a good bonding property with epoxy and polyethylene, and the last layer of the coating is that Polyethylene which has very high Chemical and Mechanical properties which are preventing a chemical reaction with Environment and wear and tear respectively.

1. Epoxy.
2. Polymer Adhesive.
3. Polyethylene.

3LPE coating

3LPE coating consists of 3 multilayer Coating:-

Layer 1

It is a Fusion Bonded Epoxy. This Epoxy provides protection against corrosion and is also fusion bonded with the blasted steel surface whose Roughness should be 50 to 70 Microns or the manufacturer’s recommendation

Layer 2

In 3LPE coating consists of a polymer and adhesive that has excellent chemical bonding properties to the inner layer (Epoxy) and the top layer of polyethylene. The adhesive material of the coating has Properties that make bonding with the same properties material.

Layer 3

This is the last layer of the 3lpe coating which is polyethylene. polyethylene is used for protection against any physical damage to the pipe. The 3 layer polyethylene-coated (3LPE) pipe is the preferred choice for the transmission of oil and gas and water etc. around the world. It can withstand varying temperatures of the environments ranging from many situations and the environment like desert, drylands to deep underwater regions. 3LPE coated pipes are also used for transportations of drinking water, oil and gas, and other fluids. The operating temperature of the 3LPE coating coated pipes ranges from -40 to 80 o C.

The function of 3LPE coating.

* The First Epoxy layer of the coating pipe, performs the anticorrosion function of the coating systems which has protested the line pipe against oxidation and corrosion.

* The second layer of the polymer coating and the adhesive keeps the first and third layers of the 3LPE (three-layer polyethylene) coating system bonded due to adhesive properties that give mechanical and chemical properties strength.

* The Third layer which is the thickest of all layers gives mechanical strength and protests 3LPE (three-layer polyethylene) coating from the mechanical damage during pipe service transportation, loading, unloading, and handling.

All three layers of the raw material have different mechanical and chemical material properties that are verified individually prior basis to using in the coating process to check complaints against the code DIN 30670, All 3 layers of the coating applications were individually tested.

3LPE coating process

The coating thickness of 3lpe coating (Minimum requirement)

Pipe size Specified outside diameter         

          <_ 273.1                        2.5

          >_ 323.9 to 457             2.8

          >_508.0 to <_762.0       3.0

          >_ 813.0                         3.3

Process of 3LPE coating

Pipe Testing:-

Before 3LPE (three-layer polyethylene coating), we proper various tests conducted like all mechanical and chemical properties test then after the visual test do and finally, ultra testing was conducted.

Water Washing:-

After the pipe testing and clearance from the authorized person pipe go the water washing to remove impurities like rust etc.

Pipe preheating:-

After water washing heating of pipe because of temperature variation record due to incoming pipe temperature, line speed variation, interruptions these all parameters are established and recorded.

Pipe blasting:-

Pipe blasted by copper slag which provides free from rust and gives roughness which makes proper bonding with epoxy. As per code standard roughness should be as per SA 2.5 surface with 50 to 70 microns.

Rust removal:-

During blasting a powder form of copper slag freezes on the pipe or base metal which is removed by dust removal.

Pipe blow:-

After rust removal to completely clean the pipe, we use a blower to blow impurities from the pipe surface.

Pipe treatment:-

It is a method of removed already formed contaminants from the stream of air, water, or similar product.

Dust treatment:-

The standard to assess dust on the cleaned steel surface is ISO 8502, preparation of steel before application of paint, epoxy, or primer, etc.

Induction heating:-

In induction heating pipe or base material heating, about 200 to 220 degrees centigrade or as per manufacturing recommended and then after epoxy primary applies. Due to the heating of the base material FBE (fusion bonded epoxy) easily melt and properly bonding with the base metal.

FBE (Fusion bonded epoxy):-

Fusion bonded epoxy coating is an epoxy-based powder coating that is widely used to protect corrosion in steel pipes. 3LPE coating is a very good bonding property with a blasted surface that is used in pipeline construction, and valves reinforcing bar, etc. FBE (fusion bonded epoxy) applies to the base metal steel surface as soon as possible becomes a solid coating by chemical cross-linking assisted by heat. It once the curing takes place the coating of the steel surfaces cannot be returned to its original form by any means.

AD(Adhesive) Coating:-

The basic principle of adhesive material is that bonds object together because they have many different bonding properties additional material functions as transparency, conductivity, durability, Elasticity.

Polyethylene coating:-

This is the last layer of the 3lpe coating that has very high chemical and mechanical properties. The chemical properties of Polyethylene make a bond with the adhesive materials and also prevent oxidation with the environment and mechanical properties that prevent wear and tear.

Automatic marking:-

This is the last process of 3lpe coating in which number marking like heat number, coating number, pipe number, length of pipe, pipe specification, and manufacturing details.

Product selection guide

High-temperature low pressure (HTLP) 60 & 65:-

* Maximum operating of the temperature of the High-temperature low pressure (HTLP) 60 & 65, between 60 to 65 degrees centigrades.

* Compatible line coating, PE (Polyethylene), PP, FBE (fusion bonded epoxy), Coal tar.

* Minimum preheats temperature 70 degrees centigrade.

* Recommended pipe preparation SA 5/2.

* Soil stress restrictions, NONE.

* Performance according to code EN 12068 and class C50.

HTLP 80:-

* The maximum operating temperature of high-temperature pressure low pressure (HTLP) between 80 degrees.

* Compatible line coating, PE (Polyethylene), PP, FBE (fusion bonded epoxy), Coal tar.

* Minimum preheats temperature 70 degrees centigrade.

* Recommended pipe preparation SA 5/2.

* Soil stress restrictions, NONE.

* Performance according to code EN 12068 and class C50, and C80.

Codes of standards for 3LPE Coating

* A thickness of all three layers measures as per code standard Annex A of DIN 30670.

* Holiday detection as per code standard annex E of din 30670.

* Peel adhesion strength as per code standard annex D of 30670.

* Impact resistance test as per code standard annex of H of DIN 30670.

* Thermal analysis as per code standard CSA Z.245.

* Code standard as per 20,AS 4321,IS3581.

3PE pipe coating uses:-

(a) 3LPE coated pipe use in oil and gas transportations.

(b) 3LPE coated pipe use in oil and gas Chemical transportations.

(c) 3LPE coated pipe use in oil and gas Water transportations.

Feature of 3LPE coated pipe:-

(a) Excellent chemical and corrosion resistance.

(b) Resistance to cathodic disbandment.

(c) The 3LPE coating prevents physical and chemical damage during handling and operation respectively.

(d) Very high life cycle with performance.

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