Page 110 - PRESS-FIT SYSTEMS FOR DIVERSE APPLICATIONS

3.0 TECHNICAL DATA
WORKING TEMPERATURES AND

PRESSURE TABLES

XPress Copper fittings have all been soldered joint, as the high temperature issues that would be revealed by low-
tested and are suitable for use with required for capillary jointing anneals the pressure tests.
approved tubes at temperatures from -20 copper tube rendering it too soft for 3. The need for higher test pressures
to 110ºC at a maximum working pressure press-fit jointing. In an existing XPress to prove the mechanical integrity of the
of 16bar throughout the temperature Copper installation, brazing or soldering joints brings with it serious safety issues.
range. should not be carried out within 300mm Testing for such a failure mode with high-
XPress Solar is approved with tube of an existing press joint as this may pressure air/nitrogen is potentially very
meeting the temperature rates shown in damage the O ring. dangerous as the energy stored in 5bar
the table below and operates from -20 to Do not braze or weld XPress carbon or air/nitrogen, when released suddenly,
200ºC at a maximum working pressure of XPress stainless steel tubes. could lead to damage to equipment or
16bar, see exposure table on page 135. PRESSURE TESTING OF CARBON more seriously, injury to personnel. HSE
XPress Stainless and XPress Carbon STEEL SYSTEMS issue guidelines for such testing should
fittings have been tested and are The following recommendations apply be strictly adhered too.
suitable for use with approved tubes concerning the testing of XPress 4. It is therefore recommended that
at temperatures from -35 to 135ºC at Carbon Steel. an initial low pressure test at 0.5bar is
a maximum working pressure of 16bar carried out, having put the necessary
throughout the temperature range. Due to the potential for corrosion and safety measures in place, to enable any
For high working pressure applications perforation of carbon steel tube and leaks to be found. Significantly leaking,
contact the Pegler Yorkshire technical fitting systems left partially drained for un-pressed or damaged joints shall be
help desk. extended periods following hydraulic replaced, but those with low leakage
testing, it is recommended that XPress
XPress Copper Gas fittings are approved Carbon Steel systems be dry air/nitrogen rates should be identified for close
for use with copper tubes to BS EN 1057 tested, up to a maximum of 3bar. inspection during the high-pressure test.
at temperatures from -20 to 70ºC and a The full loading of the O rings often
maximum working pressure of 5bar for If hydraulic testing must be undertaken resolve small leaks identified during
the following should be considered.
outside above ground pipework and 1bar the 0.5bar test. When satisfied that the
within buildings. A. The test water should contain anti- system is sound and having the necessary
corrosion chemicals with the intention safety measures in place a 1.5 times
As part of the DVGW/ BSI approvals working pressure test can be carried
process, XPress Gas fittings have passed that post testing the system shall be out as per the Copper Development
left completely full of water (suitable
the High Temperature Test at 650°C for 30 Association (CDA) Guidelines document
minutes at PN1 (copper)/PN5 (stainless). protection against freezing will also have
to be considered). ‘Pressure Testing Piping Systems’. Leaking
WET SYSTEM INSTALLATIONS joints at this stage should be identified
B. If leaving the system full of water is not
In wet system installations we recommend practical then every effort shall be made and marked for replacement. The system
all systems be thoroughly tested upon to fully drain and dry the pipe work by pressure should then be reduced to
completion. The installation may be purging with dry air. 0.5bar again to confirm that no persistent
tested to 1.5 times the working pressure Regarding the air/nitrogen testing of pipe low-pressure leaks are present.
of the system, up to a maximum of 16bar.
If higher test pressures are required work with XPress Carbon Steel crimped NOTE: The maximum temperature
fittings the following points will need to
advice should be sought from Pegler and pressure range in any system is
Yorkshire. be considered. dictated by the component with the
1. The air should be clean, dry and free
ACHIEVING LOW TEMPERATURES lowest performance rating.
from oil. Excessive oil carried over in
For products used in water systems, compressed air may be detrimental to the
working temperatures of less then 4°C EPDM seals. This is not a problem with
can only be achieved if antifreeze is nitrogen.
added to the system.
2. Air is many times more searching than
LOCALISED ANNEALING OF water. Hence, if the purpose of the air
COPPER TUBE test is only leak detection, then 0.5bar
XPress Copper installation should not be pressure will be more than sufficient.
carried out within 300mm of a brazed or Higher pressures can in fact mask sealing

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