Page 128 - PRESS-FIT SYSTEMS FOR DIVERSE APPLICATIONS

3.0 TECHNICAL DATA
SYSTEM DESIGN CONSIDERATIONS

AND TUBE EXPANSION

EXPANSION AXIAL COMPENSATORS We have the following specific recommendations for XPress systems:
The axial compensator is an expansion joint with a corrugated bellow in Every effort should be made to ensure that the pipework and fittings
the centre and is supplied with press ends in sizes 15 to 54mm (SS75) or are clean and dry prior to the fitment of insulation. To help to achieve
with male ends in sizes 76.1 to 108mm (SS76). this, the avoidance of water based media for leak detection should be
The axial compensator provides a solution for expansion and shrinking considered.
of your piping system whilst dampening vibrations and eliminating Where Carbon Steel systems are used every effort should be made
unwanted noise. Manufactured from stainless steel, they are suitable for to protect the system from both internal and external corrosion.
a wide range of applications from ship building, chemical industry, and Both fittings and tubing should be stored undercover in a clean dry
utility piping systems. The axial compensator provides flexibility where environment prior to installation.
space is limited. Special consideration should be given to the effects of condensation on
fittings and pipework. This may be caused by surrounding works during
the construction cycle and not by the system itself.
The choice of insulation system should not be considered as the only
means of preventing corrosion, the specifier must consider the whole
process and the potential risk of corrosion taking place.
After initial installation, suitable vapour barriers need to be considered
to ensure that NO WATER INGRESS is allowed to permeate the
insulation.
Xpress Carbon and Tectite Carbon systems should not be installed
SS75 Expansion Axial SS76 Expansion Axial in externally or exposed locations without due consideration to
Compensator Compensator Drum End
weathering protection. We would recommend that Stainless Steel or
Xpress Copper be used for such applications.
MATERIAL SPECIFICATION PHENOLIC FOAM
When using rigid phenolic foam (or other thermal insulation) to lag
Component Connections Materials pipework, always remember to refer to the lagging manufacturer’s fixing
instructions. To avoid the risk of external corrosion of copper pipework
lagged with this foam, the European Phenolic Foam Association
SS75 15-54mm Press Ends Stainless Steel 1.4404 (AISI 316L)
recommend that such insulation products be installed with a moisture
barrier. As a precautionary measure, Pegler Yorkshire does not
SS76 76.1-108mm Male Ends Stainless Steel 1.4401 (AISI 316) recommend any anti-corrosion materials containing a mineral oil base
are applied around the mouth of the fitting and this should instead
Bellows Stainless Steel 1.4571 (AISI 316 Ti) be protected using silicon grease (or similar) to form the atmospheric
Multi-Ply
barrier between the metal and the foam insulation.
An alternative would be to use an impervious material, such as PVC
O Ring Ethylene Propylene Diene Monomer
tape. This needs to be applied to the mouth of the fitting before
applying any mineral oil-based materials. If a grease-free installation is
INSULATION preferred then butyl tape can be used to provide a vapour barrier.
For all XPress Systems, we recommend you adhere to the insulation Some manufacturers of this type of lagging supply their products with
requirements as specified by the Water Supply (Water Fittings) an internal, factory-applied silicate barrier to prevent external corrosion
Regulations and Building Regulations 1999. These requirements are problems. However, if you do need to add a barrier product, we
equally applicable to plastic pipe and stainless steel tube. recommend that all XPress fittings be fully installed before these are
applied and that they are completely coated.
Pegler Yorkshire would always recommend that any insulation should be
fitted in accordance with:
The Code of Practice BS5970:2012
- Thermal Insulation of Pipework, ductwork,
associated equipment and other industrial
installations in the temperature range of -100ºC
to +870º C.
Additional guidance can be found on an insulation manufacturer
website.

128