aerospaceclimate controlelectromechanicalfiltrationfluid & gas handlinghydraulicspneumaticsprocess controlsealing & shielding
Transair Specification DocumentAluminium pipework for compressed air & vacuum
Transair diameter 168 mm (6")
This document is intended to be used by organisations working with compressed air networks and
centralised vacuum networks, to help them write their project specifications.
Aluminium piping systems are a relatively new technology and their use is becoming more and more
frequent. It is important to list the certifications and guarantees that an aluminium pipework should
have to ensure safe and efficient use.
The Transair specification document lists all requirements that a compressed air or vacuum system should meet in terms of safety, reliability, efficiency and sustainability.
To ensure the quality of the manufacturer and of their solution, importance should be placed on com-
pliance to ISO 9001 certification: this certifies the quality management system of the manufacturer.
The safety of equipment under pressure is regulated by two main standards: ASME B31.1 and
B31.3 for North America and the Pressure Equipment Directive 97/23/CE in Europe. Compliance
AD 2000 Merkblatt confirms that a system has been assessed by TV Rheinland.
Finally a manufacturer, who has proven experience and a certified management system, is able to
give a 10 year guarantee on their products.
All pipework within a building has to be easily identifiable, the best way being to use different colou-
red pipe for each network. Our suggestion is to use blue (RAL 5012, equivalent to BS 1710) or grey
(RAL 7001). The pipe should have the QUALICOAT label which guarantees the quality of the pain-
ting process, the chemicals used, the finished quality and resistance of the pipes exterior surface.
Installers and end users will need to create drops and take off points from the main network; these
drops could be vertical or horizontal. The piping solution should offer an easy way of aligning these
drops along the pipe. Therefore, two marker lines should be printed on each pipe (at an angle
of 0 and 90) and the two lines should have a maximum deviation of 3 mm throughout the total
length of the pipe.
To allow easy handling and to avoid bending under stress, the length of 16.5 mm pipe should be 3
m or 4.5 m. On diameters 25 mm, 40 mm, 63 mm, 76.3 mm, 101.8 mm and 168.3 mm, the pipe
should be 3 m or 6 m.
Pipe is the main part of any system; major attention should be given to the
quality of the pipe in order to guarantee safe and efficient use.
On compressed air or vacuum networks the following aluminium alloy
should be used: either AW-6060 with a T51 thermal treatment or AW-
6063 with a T5 thermal treatment. Conformity of the alloy is given by three
different attributes which correspond to three different standards: the che-
mical composition is defined in EN 573.3 and ASTM B241 (for the US),
conformity of the thermal treatment is defined in ISO 2107 and the me-
chanical characteristics are defined in EN 755-2. For safety reasons and
to ensure a good connection with the fittings pipe must be calibrated
according to Transair standards.
To ensure easy handling without affecting the performance on smaller diameters, the fittings should
be made of high quality plastic. Fibre glass reinforcement will increase impact resistance wit-
hout increasing the weight.
The stainless steel gripping ring is a main safety feature: it keeps the pipe connected to the fitting.
The mechanical characteristics of this ring are dictated by the type of alloy used, since there are
various grades of stainless steel. The gripping ring material should be Z10 CN 18 (as defined in
EN 10151 standard) to guarantee optimal resistance to bending under pressure or unintentional
One of the main advantages of modular aluminium piping systems is a continuous leak free connec-
tion. This is possible with the use of high quality seals, some NBR may become damaged over time
or due to temperature variations. We have completed stringent testing on our seals and conclude
that NBR HD50 or NBR HD70 is suitable for chemical resistance to moisture and compressor oils
over time, and for temperature variations within our specifications.
For fire resistance, the UL94 certification defines the reaction of products when exposed to fire. For
a compressed air network, the fittings should be at least of HB class and the support clips rated
Under use, several changes may be required to the initial layout of the system. For ease of modifi-
cation and improvement of the network, the piping solution should be capable of lateral dismant-
ling (i.e. the possibility of dismantling a pipe or a fitting without having to disassemble other parts
of the system).
Diameters 16.5 mm (1/2"), 25 mm (1") and 40 mm (1 1/2"):
The safe and secure connection is due to the application of the correct torque
setting being applied to the fitting. Therefore, it is a key safety point to have a
visual torque indicator on every connection. If no indicator is present, there is
no visual confirmation that the system has been safely connected.
Diameters 76.3 mm (3"), 101.8 mm (4") and 168.3 mm (6"):
In the same manner, the connection technology for these three larger diameters should have the
For 76.3 mm and 101.8 mm the use of treated steel clamps with high quality plastic car-
tridges will give optimal resistance without increasing the weight of fittings. For the 168.3 mm, as
the mechanical constraints are even greater, we recommend the use of a cast aluminium clamp
with a ZAMAK cartridge.
For all these three diameters, the same grade of nitrile seals should be used (NBR HD70).
On these diameters constraints are higher: Therefore, the connection method
should be adjusted accordingly. We recommend the use of a cartridge and
clamp to ensure that the failure mode will be limited to leakage, preventing
disconnection or bursting of the fitting.
Diameter 63 mm (2 1/2"):
Larger diameters require a more secure and stronger means of connection due to an increased
force being applied. Aluminium will provide a more suitable solution to allow greater resistance and
is easier to handle than traditional steel materials.
Similar to smaller diameters, the quality of the rubber seals will determine sealing integrity over time:
We recommend the use of NBR HD50 or NBR HD70.
On this diameter the constraints are higher: Therefore, the connection me-
thod should be adjusted to suit. We recommend the use of a double clamp
technology to ensure that the failure mode will be limited to leakage, preven-
ting disconnection or bursting of the fitting.
FEATURE OF THE NETWORK
To cover all kind of applications the products used should cover a wide range of pressures and
Continuous performance from atmospheric pressure to 16 bar (13 bar for 168.3 mm) at 45C,
13 bar at 60C, 7 bar at 85C and a minimum temperature of -20C with a minimum safety factor
of three. It is important to underline that the performance should be continuous starting
from the atmospheric pressure to guarantee efficiency and secure tightness even during the
loading and unloading phases of the compressor.
For vacuum the minimum pressure should be 13 mbar (absolute pressure).
Flexible hoses for compressed air and vacuum applications are regulated by different standards:
ISO 8030 for under pressure applications and EN 12115 for vacuum. These standards determine
the rules and the quality target in terms of performance and to fire resistance of the hoses.
QUALITY OF THE CONVEYED FLUID
Another important quality of aluminium pipe is its resistance to corrosion. Thanks to this feature
the flow will not be adversely affected by rust. It does not mean, however that the system will be
totally clean; fittings can cause the presence of plastic or metal particles, whilst grease and oil are
used to lubricate the seals.
The quality of compressed air for industrial applications
is defined by ISO 8573 standard (consult our dedicated
brochure for more information). Make sure the solution
you specify is rated ISO 8573-1 for class 1.1.1 applica-
tion and silicon free in order to maintain fluid consistency
throughout the network.
For the environment:
RoHS and REACH standards guarantee that no hazardous substance is present in the product
A Green Building Council can issue an approval, in many cases, based on the following crite-
ria: environmental impact during manufacturing, energy efficiency, recyclability and conformity to
The manufacturer should be able to carry out a life cycle analysis on their aluminium pipework to
ensure a lower environmental impact, especially for the largest diameter (168 mm).
The modularity of the system is key. Once installed, the layout of the network will have to remain
adaptable to meet evolving production needs. It is essential to look at two main features of the
solution: the ability to assemble and disassemble the fittings a