Coating and Lining Pipe
Pipe coatings are applied to preserve the metal from acidic environments. For such conditions, 3LPE coating is the most common type of coating. There are many types of coating, lining, and cladding that are protecting the internal and outer surface of Pipes. The internal lining shields the pipe from destructive fluids. In cladding, the pipe has a coating on the inner surface, which is done by higher grade materials to enhance the resistance ability of the pipe.
Pipe Coating
The coating helps to protect Pipes from corrosion, abrasion, and also from all mechanical stress. Pipe coating can be done by using metallic as well as for non-metallic materials on the surface of the pipe. It can be applied on Seamless or Welded types of Pipes.
There are many suitable materials to use for the coating of Pipes. The most common materials which are used widely in pipe coating are such as bituminous coatings, resins, paints, waxes, oils, varnishes, lacquers, plasticizers, Greases, Plastics such as polyurethane, Rilsan, polyethylene, PTFE, and PVC, Elastomers, Vitreous enamel, and Cement mortar. In organometallic pipe coating, paints are pigmented with different types of metals such as aluminum, zinc, lead, stainless steel in powder form.
Phosphating, phosphating, Black finishing, Chromatin, and browning are used for Coating Pipes which make them durable. 3 layers of Polypropylene (3LPP) and 3 layer polyethylene (3LPE) are perfectly suitable materials for coating Pipes which are available at low cost. This type of coating makes Pipes more rigid, durable, and also able to offer excellent resistance against corrosion.
Pipe Lining
Lined Pipes are durable and perfect to use for complex industrial applications. These pipes are implemented with an enclosed protective material, which is mechanically injected into the tubular segment. During completion of the production process, the lining substance is implemented into the pipe. The internal lining material has its thickness which reduces the bore size of the pipe. For the process of Lining the Pipes, there are many suitable materials such as Teflon (PTFE), Cement mortar, Liquid epoxy, Glass, Fusion bonded epoxy (FBE), Polyethene, Bituminous asphalt, and Zinc.
Pipe Cladding
Pipe cladding is applied to improve the durability and corrosion resistance of a pipe. This makes these Pipes widely used in all industrial sectors. But added pipes are more costly as compared to lined pipes because it requires supreme metals only. The cladding process enhanced the durability and toughness of a carbon steel pipe by corrosion resistance quality as compare to stainless, duplex, and high nickel alloys like Incoloy, Inconel, etc.). Clad pipes are known as CRA, which means corrosion-resistant alloy. The cladding process is done in the inner part of the pipe, which includes a layer of higher-grade material on the layer of the lower-grade base material.
Clad pipes are perfect to use for the application of fluids that immediately deteriorate carbon-manganese steels. The bonding among higher grade and lower grade materials is metallurgical, which is done by welding these two materials together. It can also be achieved by the explosion technique which combines it well.
3LPE coating pipe is one kind of coating method which used in carbon steel pipe. No matter which pipe it is, whether it is a seamless steel pipe, welded steel pipe, stainless steel pipe or alloy steel pipe, it can do 3LPE coating for the pipes. The Common use of 3LPE coated steel pipe is in the Pipeline Industry. As carbon steel pipe is widely used in pipeline systems for transportation of oil, gas, water and other fluids.
Features of 3LPE Pipe Coating
· 3LPE coating Steel pipes has high tightness, as it can save energy, reduce costs, protect the environment in long-term operation.
· Corrosion resistance of a 3LPE coated steel is very strong.
· Resistant to Cathodic Disbandment
· Has High Performance and Extended Life Cycle
· This Pipe has a service of 30-50 years long.
· High strength epoxy. PE absorbent and hot melt adhesive softness, etc. have high corrosion reliability.
Layers of Coating
The 3LPE Coated pipes have 3 Layers of Coating.
· Layer 1: The First layer is of fusion bonded epoxy, which protects pipe from corrosion when needed.
· Layer 2: Layer of Copolymer Adhesive who has a natural bonding with the inner layer and the top
· Layer 3: Polyethylene Coating which helps the pipe to avoid any physical damage
3LPE Coated pipes used for transmission of oil and gas as it can withstand a temperature higher than the other pipes. It can withstand varied temperatures from dry land desserts to underwater pressures, hot temperatures to cold winters. The 3-layer coating help withstand all weather conditions and polyethylene coating helps withstand physical damage.
Advantages of 3LPE Coating Pipes
1. Durable Lifetime
3LPE coated steel pipe has a service life for above 50 years. It is because 3LPE coating has good stability and anti-aging performances, which works under normal temperature and pressure conditions.
2. Corrosion Resistance
The elements of PE structure stability are high. So, we can use it to prevent corrosion from natural gas, liquefied petroleum gas, artificial gas, and other chemical subjects. And it needs no secondary anti-corrosion equipment. The chemical of soil does not produce any effects on the steel pipe using 3LPE coating.
3. Flexibility
3LPE coating is a kind of soft and flexible material, it breaks after prolong 5 times longer. It is easy to bend without damage. 3PE coating steel pipe can bypass steel pipe and reduce the fees of installation.
4. Safe and reliable connection way
3LPE coating steel pipe mainly uses hot melt and fused connection, which connects the interface and pipeline as a whole. There is no water and gas leakage in this coated steel pipe.
5. Light and easy to move
3LPE Coated pipe is light in weight. It only accounts 1/8 weight of steel pipe. Because of its characteristics of softness and corrosion resistant properties, it is easy to move, and easy to bend. Welding process of this pipe coating is convenient and fast.
Three (3) Layer Side Extruded Polyethylene (3LPE) Coating | conforming to ISO 21809, Class B |
Size range | 25 mm to 3000 mm |
Length | 6 – 12 meter |
Coating thickness Maximum | 4.2 mm |
3lpe coating testing Method | CSA Z245.20, ASTM D149, D257, D790, D1603, D1693, ISO 1183, ISO 1133, ISO 15512, ISO 527-2, ISO 306 |
3lpe coating temperature range | (-) 40 °C to (+) 80 °C. |
Bendability | Yes |
3lpe coating standard |
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PE pipe material |
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PE Anticorrosive coating | ISO 21809-1 |
Marking on coated 3LPE Line Pipe |
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PE Coated Pipe Hardness | Shore D, > 55 |
Test Certificates available | a) Epoxy Powder
b) Adhesive
c) Polyethylene
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Three Layer Poly Propylene (3LPP) coating 3LPP coating system is a multilayer coating composed of three functional components: a high-performance fusion-bonded epoxy (FBE), followed by a copolymer adhesive and an outer layer of Medium Density Polypropylene (MDPP) or High-Density Polypropylene (HDPP), which provides protection against external corrosion.
The codes and standards for 3LPP Coating are DIN 30678, ISO 21809-1, NFA 49-711, SHELL DEP 31.40.30.31-CSPC
DIN 30678-2013 Polypropylene coatings on steel pipes and Fittings
ISO 21809-1:2011 Petroleum and natural gas industries — External coatings for buried or submerged pipelines used in pipeline transportation systems — Part 1: Polyolefin coatings (3-layer PE and 3-layer PP)
NFA 49-711 External Coating with Three Polyproplene Layers Coating, Application by Extrusion
SHELL DEP 31.40.30.31-CSPC External Polyethylene and Polypropylene Coating for Line Pipe
Fusion Bonded Epoxy (FBE): First layer of FBE shall be 150 microns thick.
Adhesive: Second layer of extruded co-polymer adhesive, 200 microns thick.
Polypropylene (MDPP/HDPP): Third layer of extruded polypropylene (MDPP/HDPP), 1.6 – 2.95 mm thick.
Application of Coating:
Surface preparation of pipe by sandblast cleaning (SSPC-SP10/NACE No.2/ISO 8501-1 Sa 2 1/2/SIS 05 59 00)
Subsequent to pipe heating fusion epoxy powder shall be applied
Extruded adhesive shall be applied over the pipe.
Finally extruded polypropylene (MDPP or HDPP) layer shall be applied over the adhesive layer.
Total coating thickness is generally < 3.0 mm for pipe dia < 24″ and 3.3 mm for pipe dia 32″ & above)
Fusion Bonded Epoxy (FBE) coating protects pipe surfaces against corrosion. Double or triple layers of FBE may even increase the resistance to friction and abrasion. FBE coating is also used as the primer layer in 3-layer PE/PP coating systems.
Electrostatic epoxy powder is sprayed onto a pipe at a temperature typically around 220 – 235°C. On reaching the hot pipe surface, the epoxy powder melts and forms a uniform layer of epoxy coating on the pipe.
An internal FBE coating is used to protect the inner surfaces of steel pipes from the influence of corrosion and light mechanical impacts and it provides excellent resistance to cathodic disbondment.
The internal Fusion Bonded Epoxy (FBE) system is based on an epoxy powder spray system, mounted on a lance. The lance moves through the pipe while the epoxy powder is sprayed onto the internal pipe surface. The pipe must be heated so that the epoxy powder melts onto the pipe. After FBE application, the layer requires curing.
FBE can be applied at service temperatures of up to 110 ℃; the typical thickness is 350 to 450 mm. A second layer creates an excellent resistance to damage for the pipeline itself, even under the most difficult environmental conditions.
The codes and Standards for FBE Coatings:
AWWA C213 Standard for Fusion Bonded Epoxy Coating for the Interior and Exterior of Steel Water Pipelines
These standards describe the material and application for shop and field-applied, liquid-epoxy interior linings and exterior coatings and linings used in the water-supply industry for steel water pipelines installed underground or underwater, under normal construction conditions.
API RP 5L7 Recommended Practices for Unprimed Internal Fusion Bonded Epoxy Coating of Line Pipe
This Recommended Practice provides for UNPRIMED INTERNAL FUSION BONDED EPOXY COATING OF LINE PIPE for use in transportation pipelines in the petroleum industry. Especially for the FBE Coated Line Pipes that transport via Railroad.
CAN/CSA Z245.20, ISO 21809-2, API RP 5L9, AS 3862, SHELL DEP 31.40.30.32.
CAN/CSA Z245.20 External Fusion Bond Epoxy Coating for Steel Pipe
ISO 21809-2:2014 Petroleum and natural gas industries — External coatings for buried or submerged pipelines used in pipeline transportation systems — Part 2: Single layer fusion-bonded epoxy coatings
API RP 5L9 External Fusion-Bonded Epoxy Coating of Line Pipe
AS 3862 Standard Specification for External Fusion-Bonded Epoxy Coating for Steel Pipes
SHELL DEP 31.40.30.32 Technical Specification for External Fusion-Bonded Epoxy Powder Coating for Line Pipe
Application of Coating:
Surface preparation of pipe by sandblasting cleaning (SSPC-SP10/NACE No.2/ISO 8501-1 Sa 2 1/2/SIS 05 59 00)
Subsequent to pipe heating fusion epoxy powder shall be applied.
Epoxy Coated Pipes Statistics | |
Color | various options available |
Thickness range | 0.004″ to 0.006″ |
Temperature | 300°F maximum |
Chemical Resistance (ASTM D543) | Excellent |
Adhesion (ASTM D4541) | 1933 psi |
Hardness (ASTM D3363) | > 8 H |
Standard |
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Marking for FBE Coating Pipe |
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Solvent free epoxy coating color code |
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Cement Lined Steel Pipes are a metal pipes coated with a cement mixture of mortar. The mixture could have different compositions. But the mixture could be applied locally by hand or with machines. Depending on the nominal size of the pipes, the thickness of the cement mixture or the mortar will vary. The Concrete Coated Pipes has to be used with care. Since the cement can crack easily under impact momentum, the use of tools is recommended. The tools are usually layered with rubber to avoid sudden impact energy transfer. There are different grades of the mortar lining. The AWWA C205 Cement Mortar Lining is a standard of the cement applied as coating to the pipe. There are different standards and grades of the cement that govern the quality, thickness and diameter of the coated pipes and cement. The c205 standard covers pipes from 2 inches to 24 inches in nominal pipes size. The concrete or cement thickness ranges from 0.25 inches to 0.375 inches increasing with the nominal pipe size. Also there are limited span sizes for each type of pipe. The maximum span size under this standard is 50 feet.
Concrete Coated Steel Pipes are used in many industries such as potable water and sewage applications mainly. These are good remain and be stable. If the Concrete Lined Steel Pipe is moved regularly, the cement might crack. If the crack in the cement lining is not repaired correctly, the Cement Lined Ductile Iron Pipe might get a leak in between the cement and the metal. This can corrode any standards such as the AWWA C104 Concrete Lined Steel Pipe. So the Concrete Lined Steel Pipe has to be dealt with care. The Cement Lined Steel Pipe or the Cement Mortar Lined Steel Pipes are common in carbon steels. The application of the Cement Lined Carbon Steel Pipe reduces the cost by eliminating the need for anticorrosive pipes but it increases the risk of cracking of cement during handling.
Standard Specifications | ASTM, API, GB, BS, DIN, BS 1387, BS EN10217, API 5CT, API 5L |
Thickness | 1 – 100 mm |
Section Shape | Round |
Outer Diameter | 25 – 3000 mm |
Material | API 5L, Carbon Steel Pipes |
Types | Seamless, Welded, ERW, SSAW |
Cement mortar lining Industry Code & specification |
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