Gas Pex Couta Group

Technical Structure.


Gas Pex pipe is a macro composite pipe of five layers. The inside layer is made of cross-linked polyethylene (PEX), overlapped welded by an aluminium layer, then covered by the outside cross-linked polyethylene PEX layer. Between the aluminium layers are the bonding adhesive layers. All layers are extruded in one step.

Gas Pex pipe uses a special PEX material which is hygienic, toxic free and smooth. The middle aluminium layer is 100% gas/oxygen tight. This structure provides Gas Pex pipe the advantages of both metal and plastic while avoiding their individual weaknesses.

The product has been independently tested to demonstrate conformance to the requirements of AS 4176 Polyethylene/aluminium and cross-linked polyethylene/aluminium macro composite pipe systems for pressure applications.

To view our SAI Global approval click on this link:

Gas Pex Supplier Approval to AS 4176

 


Thermal & Pressure Resistance

Note:1Mpa = 145psi = 10bar

Specification

Aluminum
(mm)

Minimum burst
pressure (MPa)

Min pipe ring
strength (N)

long-term hydrostatic
strength (MPa)

working temperature(℃)

working pressure

(mm)

(inch)

pipe A

pipe B

pipe C

pipe A,B

pipe C

1014

3/8

0.2

7.0

2300

2.7

-40~60

-40~95

-20~40

1.0

0.4

1216

1/2

0.2

6.0

2300

2.7

1418

9/16

0.2

6.0

2300

2.7

1620

5/8

0.25

5.0

2500

2.7

2025

3/4

0.25

4.0

2500

2.3

2026

3/4

0.3

4.0

2500

2.3

2632

1

0.3

4.0

2500

2.1

3240

11/4

0.33

4.0

3500

2.1

 


Thermal Conductivity
0.45W/m.k, about 1/100 that of steel pipe but only several times higher than that of insulating materials.

 


Corrosion Resistance

The inside and outside polyethylene are a kind of symmetrical and non-polar material with stable characteristic. At normal temperature, it does not dissolve in any known solutions and is resistant against various kinds of acid, alkali and salt.

 

Weathering Quality and Working Life


It can be concluded from this graph that if utilized under the stipulated conditions and pressures, GAS PEX Pipe can have a working life of more than 50 years.

 

 

 

 


Burning Resistance

The PE(X)- AL -PE(X) composite structure acquires GAS PEX Pipe a much better burning resistance than that of all polyethylene pipe.


Hydraulic Function

The roughness coefficient of GAS PEX Pipe is 0.007mm. The inside wall is very smooth, scale free and low flow resistant which makes GAS PEX Pipe ideal for fluid (such as water) carrying. Due to her hard but flexible composite structure, the lashing pressure is quickly eliminated, thus no disturbing sound occurs.

 


Oxygen-permeability of various kinds of plastic pipes


Installation
Bendable but never spring back, decreases lots of fittings attached, easy installation, spares lots of installation time.
Other advantages

The core layer of Aluminium guarantees static resistance, lightness and oxygen tightness, it also ensures no growth of micro-organism inside water pipe and the safety in gas supply.

 

 



Coefficient of heat expansion


25×10-6m/m.k, only 1/8 that of all polyethylene pipe, almost the same as that of aluminium pipe.

(see table)