External coatings
The purpose of an external coating is to provide a durable protection against corrosive soils. PAM offers a complete range of external coatings to meet all cases of corrosive soils and respecting EN 545 Standard.
The external coatings of PAM pipes and fittings, according to the EN 545 specifications, can be divided into three categories according to the kind of corrosive soil:
- standard coatings suitable for the vast majority of soils,
- supplementary protections, for highly corrosive soils,
- special coatings, for extremely corrosive environments.
Specification on the field of use of ductile iron pipes’ external coatings according to European standard EN 545
| Situation | ZINALIUM Znal 85-15 400g/m2 + Pore sealer | CLASSIC Zn 200 g/m2 + Pore sealer | TT PE or PUX |
|---|---|---|---|
| Above the water table | No limit (except situations mentioned below) | Authorized for soil resistivity above 1500 Ω.cm | Authorized |
| In the water table | Authorized for soils in marine water table with a resistivity above 500 Ω.cm | Authorized for soils in marine water table with a resistivity above 2500 Ω.cm | Authorized |
| Acidic soils | Forbidden in soils with high acidic reserve (including acidic peaty soils) | Forbidden in soil with pH below 6 or with high acidic reserve | Authorized |
| Mixed soils | Authorized | Not authorized | Authorized |
| Soils containing refuse, cinders, slag or polluted by wastes or industrial effluents | Not authorized | Not authorized | Authorized |
| Occurrence of stray currents | Not authorized | Not authorized | Authorized |
| Availability in the PAM ranges | DN 60 to 600* | DN 700 to 2000** | DN 60 to 2000 |
* For DN above 600, please consult us. ** For DN below 700, please consult us
For NATURAL range DN 60 to 600
Ductile iron pipes of the NATURAL range are coated externally with a thick layer of ZINALIUM (85 Zn – 15 Al) with a minimum mass of 400 g/m2 and finished with a blue epoxy layer. Ductile iron fittings of the NATURAL range are coated with an electro-deposited epoxy with a regular thick layer of at least 70 microns, applied on a blast cleaned and phosphatized surface.
Pipes and fittings of the NATURAL range can be buried in a vast majority of soils, except:
- acidic peaty soils;
- soils containing refuse, cinders, slag or polluted by wastes or industrial effluents;
- soils under the marine water table
As well as, if relevant, soils where stray currents occur.
The table below outlines the external coatings for pipes and fittings from DN 60 to 600.
| Protection | Pipes | Fittings |
|---|---|---|
| ||
| NATURAL | ZINALIUM + (Zn Al 400g/m2 + blue epoxy) | Blue cataphoresis |
| ||
| Special | TT PE | Blue epoxy in compliance with EN 14901 |
For CLASSIC range DN 700 to 2000
Technical teams carry out soil surveys at customers' request in order to recommend the most suitable protection.
The table below outlines the external coatings for pipes and fittings from DN 700 to 2000.
| Protection | Pipes | Fittings |
|---|---|---|
| ||
| CLASSIC | Zinc + Bituminous coating | Bituminous coating or equivalent* |
| Reinforced | Basic solution + polyethylene sleeving layed on site | |
| ||
| Special |
| Powder epoxy coating |
Coatings
