Telford foundry

TT PUX - External Polyurethane

Technical solutions

TT PUX - External polyurethane

The TT PUX range from DN 800 to 2000 features a polyurethane coating deposited on the pipes in the factory. The ends, socket and spigot, are protected by a thick epoxy coating.
The TT PUX range is intended for use with highly aggressive soils. It completes the TT PE range in large diameters.

A polyurethane coating applied in PAM plants

The polyurethane coating is deposited on the pipes in the PAM plants. Internal manufacture ensures rigorous control of the coating application conditions. Each pipe is tested individually after coating by a "Holiday detector" test in order to check the protective quality of the coating (barrier forming a seal against the external environment). The polyurethane used by PAM is a solvent-free two-component system. The pipe is heated to a temperature at which the coating can be sprayed on.

For pipes in the TT PUX range :
- the pipe barrel is coated with polyurethane,
- the spigot and socket are coated with thick epoxy.

The epoxy, compliant with standard EN 14901, is used instead of polyurethane on the spigot and in the socket since this product provides equivalent protection, for a thinner coating, to obtain better control over the jointing conditions.

Highly demanding technical specifications

Due to the thickness of its polyurethane layer, the ductile cast iron pipe is fully protected against the most aggressive soils as well as during transport and handling operations.

Refer to EN 15189 for the precise definition of the test methods
1Chemical resistanceLess than 15 % weight increase after immersion in deionised water
Less than 2 % weight loss after drying
1Chemical resistanceLess than 10 % weight increase after immersion
Less than 4 % weight loss after drying
2Impact strength8 J/mm of PU on the pipe barrel coated with polyurethane
3Resistance to indentation<10% to 10 MPa
4Elongation at break>2.5%
5Specific resistance of the coating in 0.1 m
NaCl solution 
>108 Ω.m2
6Resistance ratio>0.8
7Adhesion8MPa at 23°C
8Non-porosityNo breakdown with Holiday detector

TT PUX pipe coating thicknesses

The TT PUX coating complies with European standard EN 15189.

 Average thickness μmMinimum thickness µmMaterial

The TT PUX coating can be used at permanent operating temperatures up to 50°C.

Simplified specific protection for the junctions

The TT PUX pipelines retain the ease of installation inherent to ductile iron pipelines. They require no additional protection on site after jointing. In case of anchoring fittings, a special coating must be applied on the junction.

"Hot climate" countries

In countries with hot climates (some African and Middle-East countries, in particular), TT PE coating is not recommended regarding the risks of creep of the HDPE coating during storage in the sun (temperatures may exceed 80 °C).
In this case, for diameters from 60 to 700, PAM recommends the use of TT PUX pipes.

Please contact our sales engineers to obtain the precise characteristics of these complementary products and the conditions in wich the TT PUX range should be used.

UNIVERSAL Vi or VE, and PAMLOCK, anchored joints can be used with TT PUX pipes.

See also

The purpose of an external coating is to provide a durable protection against corrosive soils.