EPC-S pipe protection systems
Epoxy composite and reinforcing tape-based coating systems have been developed to respond to extremely aggressive agents (e.g. rocky terrain, sloping terrain combined with landslides) or special uses such as pipelines laid by forced draught in tunnels made by horizontal drilling (under crossings of watercourses, roads, railways) or grooved reinforced pipelines.
The epoxy compound gives these coating systems very high chemical resistance, excellent mechanical strength, specific to reinforced epoxy resins and very good dielectric properties.
The reinforcing tapes are made of glass fiber fabric (EPC-S coating systems).
Due to the extraordinary adhesion to steel, these systems are also suitable for the repair of cracked storage tanks and pipelines.
AREAS OF APPLICATION
- Corrosion protection of metal pipes under plaster or buried tanks, bends, flanges or any body with irregular geometry.
- Corrosion protection and mechanical protection of buried metal pipes.
- Additional mechanical protection layer of pre-coated pipes with cold applied bands or extruded polyethylene in conditions where these pre-coated pipes do not meet very hard stress conditions (e.g. forced pulling in horizontal drilling tunnels).
EPC SYSTEM STRUCTURE - S
EPC - S systems are made of a first layer of two-component epoxy primer and alternating layers of glass fiber fabric treated with an epoxy composite.
After application, the multiple layers fuse together resulting in a coating with superior corrosion properties, high adhesion and extraordinary mechanical integrity which gives long lasting protection.
The system structures are determined by both the diameter of the pipe and the aggressiveness class of the soil.
Main characteristics of EPC-S systems determined according to SR EN 10289
| Characteristic | UM | System code | Value |
| Adhesion to steel (tensile method) | Kgf/ cm2 | EPC – S | ≥ 50 |
| Test voltage | KV | EPC – S | > 35 |
| Penetration resistance | mm | EPC – S | 0.15 ÷ 0.20.1 ÷ 0.15 |
| Cathodic discharge* | mm | EPC – S | 1.91 |
*IIn the test, the EPC-S insulation system behaved exceptionally well, the equivalent cathodic detachment diameter being only 0.91 mm, well below the limit for the best class in the standard, class A, the limit of 12.7 mm.
BICOMPONENT EPOXY ANTICORROSIVE PRIMER
Epoxy bicomponent anti-corrosive primer is a film-forming anti-corrosive protection product, cross-linkable with polyamide amine oligomers.
Component A contains epoxy resins, very chemically stable salts, compatible with epoxy resin, titanium dioxide, thixotropic agents and dyes where appropriate.
Component B is the hardener made of polyamide-amine oligomers, additives and pigments.
The two-component primer is made in accordance with SR EN 10289:2002.
Fields of application
If the transport environment raises particular corrosion conditions (wastewater, acid or alkaline environments, oil, etc.) the pipes are protected on the inside with a two-component epoxy anti-corrosion primer.)
TECHNICAL CHARACTERISTICS
- Binder type: epoxy - polyamide
- Product type: bicomponent - base mixture: hardener 2:1 - 4:1
- Solid % by volume: min. 100%
- Shelf life in hermetically sealed packaging: 12 months
- Drying at 20o C and 65% hygrometry - wet film: 100 microns
| Surface drying | Deep drying | Total curing |
| 12 h | 24h | 7 zile |
Drying times are prolonged by changes in film temperature.
Lack of air or poor air circulation, excessive humidity, interfere with drying and cause drying to be slower and possible deterioration of film performance.
Drying according to substrate temperature - 100 micron wet film.
Support temperature | Surface drying | Deep drying | Total curing |
5oC | 16h | 36h | 14 days |
10oC | 12h | 24h | 14 days |
15oC | 8h | 16h | 14 days |
23oC | 6h | 12h | 7 days |
35oC | 4h | 8h | 7 days |
The product is not required before it is fully cross-linked. After this and especially in the case of pipes for the transport of drinking water, they are filled twice with fresh water and left for 24 hours each time, after which they are rinsed with a jet of water.
Implementation:
- Average temperature: 5 - 30o C
- Average relative humidity: max. 65%.
- Temperature support: 15 - 40o C
- Product temperature: min. 15o C
In case of application at temperatures below 5o C and hygrometers above 65%, the drying and recoating time values are increased by 2/3 times (depending on the actual temperature).
Temperatures above 15o C are required for complete curing.
Support preparation
Degreasing and sandblasting is mandatory. The primer must be applied within 4 hours of sandblasting.
Weighing and not volumetric dosing is recommended as this gives errors due to the varying densities of the components in different deliveries. After perfect mechanical homogenization, the mixture of the two components must be kept for a pre-reaction time of 10 minutes at 23 ± 2oC, which must be observed before dilution. The mixture has a pot life of maximum 1 hour at 20oC. Only the amount possible to use within the viability period of the mixture shall be prepared. The pot life of the mixture decreases with increasing temperature and amount of mixture due to acceleration of chemical reactions due to the temperature released from the polyamide epoxy reaction.
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