Multi-layer coating – APC3
Polyethylene or polypropylene extrusion multi-layered coating. Provides the pipe with optimal protection against corrosion in all types of terrain. This coating excels in its great mechanical strength and excellent chemical protection (given to it thanks to the excellent barrier qualities of the materials comprising the coating). The coating is particularly suitable for lines in which a supplementary Cathodic protection is installed. The APC coating conforms to standards: Chemical Industry requirements 266.5, SI5089, SI30670, EN10288, DINEN 21809-1.
Technical information
This specification describes the requirements and property of the pipeline (APC steel pipeline coated with extruded polyethylene). APC pipes coated with polyethylene on the outside in a factory method with extrusion technology (Extrusion Coating).
The pipes are dedicated for the conduction of fluids at a temperature which does not exceed 70C⁰ and are suitable for burial in the ground or under water.
Sorting & Naming
Sorting and naming the coating according to the number of layers and coating as follows:
2.1 Three layered polyethylene coating: APC-3
2.2 Three layered polyethylene coating with 20mm compressed concrete on top of it: APC-4
Materials & Coating
Pipes and materials
The pipes and materials used to make the coating will conform to the standards and specifications which apply to them, as specified below:
Pipes
Pipes conform to the Chemical Industry requirement 266.
Materials
- Epoxy primer
Special epoxy suitable for application on a heated pipe which undergoes curing from the pipes own heat.
- Adhesive
Thermoplastic copolymer based on Polyolefin resins with polar groups and is used to glue the coating layer to the pipe surface.
- Coating material
Medium density polyethylene containing dye materials and stabilizers against radiation and oxidation.
Coating layers
The coating of the pipe is comprised from three layers that are glued by heat between them as follows:
- Primer layer
A primer layer and base for the coating which is made from epoxy resin with a thickness of 60 µ.
Adhesive layer
An intermediate layer of adhesive material designed to connect between the epoxy layer and the coating layer.
Coating layer
An external layer of polyethylene or dyed and stabilized polypropylene.
Sorting & Naming
Sorting and naming the coating according to the number of layers and coating as follows:
2.1 Three layered polyethylene coating: APC-3
2.2 Three layered polyethylene coating with 20mm compressed concrete on top of it: APC-4
Materials & Coating
Pipes and materials
The pipes and materials used to make the coating will conform to the standards and specifications which apply to them, as specified below:
Pipes
Pipes conform to the Chemical Industry requirement 266.
Materials
- Epoxy primer
Special epoxy suitable for application on a heated pipe which undergoes curing from the pipes own heat.
- Adhesive
Thermoplastic copolymer based on Polyolefin resins with polar groups and is used to glue the coating layer to the pipe surface.
- Coating material
Medium density polyethylene containing dye materials and stabilizers against radiation and oxidation.
Coating layers
The coating of the pipe is comprised from three layers that are glued by heat between them as follows:
- Primer layer
A primer layer and base for the coating which is made from epoxy resin with a thickness of 60 µ.
Adhesive layer
An intermediate layer of adhesive material designed to connect between the epoxy layer and the coating layer.
Coating layer
An external layer of polyethylene or dyed and stabilized polypropylene.
Requirements and Tests
Level of cleanliness and roughness
The cleanliness level is tested according to standard 8501-1.
The level of roughness is examined after the cleaning according to standard ISO 4287.1.4.2, overall thickness of the coating, the minimal thickness of the coating will be according to Israeli Standard 5089 or Israeli Standard 30670.
Coating continuity
The coating should be continuous (without holes). The coating is considered continuous if in an Electric Arc test at a voltage of 10Kv per millimeter thickness of the coating a breach is not detected.
Adhesion strength
When testing the coating according to Section 5.3.3 in Standard DIN 30 670 of 1991 no less than 24 hours post production, the average force (minimal) required to separate the coating from the pipe will be no less than as described in table No.1:
| Test at 0±5⁰C C5 | Test at -20±5⁰C C | Type of coating |
| At least 35N per centimeter | At least 100N per centimeter | APC-3 |
Mechanical appropriate resistance
Testing according to Standard DIN30670 Annex H.
Percentage of lengthening when tearing
Testing according to Standard DIN EN ISO 527.
Specific electrical resistance of the coating
Testing according to Standard DIN30670 Annex J.
Resistance to Cathodic Disbonding test according to Standard DIN30670 Annex C.
Shrink Tapes
A shrink tape type SHT-330 is used to wrap welding heads and pipe accessories in the field. The role of the tape is to protect the welding from corrosion. The tape is comprised from a cross-linked polyethylene and an internal layer made from a Butyl rubber based compound.
Characteristics
- No primer is required prior to coating with a shrink tape.
- The tape has excellent durability against corrosion, impact and penetration.
- The tape has excellent durability against periodic changes in temperature, ground stress, hydrostatic pressure and chemical corrosion.
- The tape excels with great durability against Cathodic Disbonding, microorganisms and bacteria.
- Easy application in all pipe diameters and suitable for repairs and for coating all types of accessories in the field.
- No expert workers are required for application. The tape is applied within minutes by using a gas blowtorch.
Technical Information
Uses
- Anti-corrosive protection of head connections of water and gas pipelines.
- Anti-corrosive protection of pipeline accessories such as arcs, tames, connectors etc.,
Installation
- Clean the weld with a mechanical steel brush.
- Heat the welded area or the area designated for coating to a temperature of 60⁰
- Attach the end of the tape to the wrapping starting point, heat with a gas blowtorch and fasten the tape to the surface using a glove.
- Wrap the tape around the pipe in the area designated for wrapping with an overlap of at least 15mm (do not use a primer).
- At the end of the wrapping cis to the pipe, start with one end and continue to the other end, heat evenly around the pipe, ensure the escape of trapped air, wait for complete cooling.
Shrink Sheets
SHS-340 type shrink sheet is intended for the complete wrapping of weld heads in the field. The role of the sheet is to protect the weld from corrosion. The sheet is comprised from a cross-linked polyethylene and an internal layer made from a Butyl rubber based compound.
Technical Information
Characteristics
- Excellent durability against corrosion, impact and penetration.
- Excellent durability against periodic changes in temperature, ground stress, hydrostatic pressure and chemical corrosion.
- Excellent durability against Cathodic Disbonding, microorganisms and bacteria.
- Easy application in all pipe diameters and suitable for repairs and for coating all types of accessories in the field.
- No expert workers are required for application. The sheet is applied within minutes by using a gas blowtorch
Uses
- Anti-corrosive protection of head connections of water and gas pipelines.
- Anti-corrosive protection of head connections of communication and electrical power supply pipelines.
Installation
- Clean the weld with a mechanical steel brush.
- Heat the welded area or the area designated for coating to a temperature of 60⁰
- Remove the protection sheet from the shrink sheet. Center the sheet to overlap the pipe’s coating from both sides of the weld.
- At first heat the patch sheet and attach it to the entire width of the shrink sheet.
- Heat using a gas blowtorch. Start heating from the weld, heat the perimeter around the pipe in order to shrink the sheet. Continue heating towards the edge of the sheet while making sure to release trapped air.
- Wait for complete cooling before touching the pipe.