Chantier Irrigal

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External coating

Technical solutions

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

External coatings
SituationZINALIUM
Znal 85-15 400g/m2  + Pore sealer
CLASSIC Zn 200 g/m2  + Pore sealerTT
PE or PUX
Above the water tableNo limit
(except situations
mentioned below)
Authorized for soil
resistivity above 1500 Ω.cm
Authorized
In the water tableAuthorized 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 soilsForbidden in soils with
high acidic reserve (including
acidic peaty soils)
Forbidden in soil with pH
below 6 or with high acidic
reserve
Authorized
Mixed soilsAuthorizedNot authorizedAuthorized
Soils containing refuse,
cinders, slag or
polluted by wastes or
industrial effluents
Not authorizedNot authorizedAuthorized
Occurrence of stray
currents
Not authorizedNot authorizedAuthorized
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.

ProtectionPipesFittings
  • NATURAL range (DN 60 to 600)
NATURALZINALIUM + (Zn Al 400g/m2
 + blue epoxy)
Blue cataphoresis
  • TT Pipeline (DN 60 to 600)
SpecialTT PEBlue 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.

ProtectionPipesFittings
  • Basic solution (DN 700 to 2000)
CLASSICZinc + Bituminous coatingBituminous coating
or equivalent*
ReinforcedBasic solution + polyethylene sleeving layed on site
  • TT Pipeline (DN 700 to 2000)
Special
  • TT PE DN = 700
  • TT PUX DN 800 to 2000
Powder epoxy coating

 

Coatings

Biozinalium
The long-lasting coating made of a layer of Zinc-Aluminum alloy enriched with Copper and a protective Aquacoat layer.
The standard PAM pipe coating consists of a layer of sprayed metallic zinc covered with bituminous paint.
Polyethylene sleeving is a tubular film of low density polyethylene slipped over and snugly fitted to a pipe at the time of laying.
The TT PE range from DN 60 to 700 features a high-density polyethylene coating coextruded onto the pipes in the factory.
The TT PUX range from DN 800 to 2000 features a polyurethane coating deposited on the pipes in the factory.