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HDPE & Industrial Plastics

Learn about HDPE / PE100 and find the best industrial plastic pipe product for your job

All You Need To Know About
High-Density Polyethylene & Industrial Plastics

Read our useful information, based on critical properties such as strength, melting point and other thermal qualities. Along with resistance to abrasion, corrosion, chemicals, solvents, acids, bases, fatigue, crushing and UV radiation. Plus identify adaptability based on your specific application, such as translucent piping, colour pigments and performance improvement additives. Once you’ve identified a plastic, browse our product range.

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About High-Density Polyethylene / HDPE / PE100 / PE / PEHD / Black Poly

High-density polyethylene (HDPE, PE100) or Polyethylene High Density (PEHD), also known as Black Poly or Blackpoly in the industry is a polyethylene thermoplastic made from petroleum. Known for its large strength to density ratio, it is commonly used in the production of plastic bottles, corrosion-resistant piping, geomembranes, and plastic lumber and is commonly recycled. The density of HDPE (0.93 to 0.97g/cm3) is only marginally higher than that of low-density polyethylene, with low polymer branching, giving it stronger intermolecular forces and tensile strength. The difference in strength exceeds the difference in density, giving HDPE a higher specific strength. It is also harder and more opaque and can withstand somewhat higher temperatures 120°C (248°F) for short periods, 110°C (230°F) continuously. High-density polyethylene, unlike polypropylene, cannot withstand normally required autoclaving conditions.

General Properties

Terms frequently used to describe this material when used for engineering applications are high density (HDPE), medium density (MDPE) and most recently high performance (HPPE) polyethylene. Others PE types, such as low density (LDPE) and linear low density (LLDPE) are sometimes used for irrigation pipelines. The Type 50 PE of AS1159 that was in common use until 1994, is an HDPE with a long-term design stress of 5.0 MPa. AS/NZS4130 and AS/NZS allow for three specific classifications by material strengths and sub classifications by performance at elevated temperatures. PE100 material’s minimum required strength is 10 MPa. Our bends are manufactured to AS/NZS 4130 from polyethylene’s complying with AS/NZS 4131. Please see our easy to follow quick reference Table of Properties.

Table of Properties

Composition

The compounds used in some pipes and fittings are pre-compounded resins, either black or coloured with pigment, complying with AS/NZS 4131. The following additives, if used, are added to the PE polymer base resin during the compounding process by the raw material manufacturer. Anti-oxidants are used to inhibit oxidation of the polymer at the compounding stage and during subsequent processing. The oxidation induction test is an indicator of the efficacy of this additive and the residual amount after processing. Carbon black is used in all black pipe at a concentration of 2.25 ± 0.25% by mass as an ultra violet radiation absorber. In natural and coloured PE materials, chemical ultra violet absorbers are used in lieu of carbon black.

Thermal Qualities

The co-efficient of thermal linear expansion of polyethylene varies with temperature but at ambient lies in the range 1.2 to 2.4 x 10-4 per degree C. In broad terms, this is about twenty times that of steel, and therefore unrestrained pipe will expand or contract much more than the steel structure that may be supporting it. Should the pipe be fully restrained, the strain due to thermal change will generate stress in the material. However due to the relatively low tensile deformation modulus (E) of PE and assuming a typical ambient temperature fluctuation of less than 40°C it can be assumed that the safe allowable stress will not be exceeded. Over the longer term, stress relaxation will increase the ability of PE to accommodate high thermal strains. The conductivity of polyethylene varies with temperature almost linearly and is typically 0.47 W/m.K at 0°C to 0.37 W/m.K at 70°C. The specific heat of polyethylene varies with temperature from 1800 Joules/kg.K at 0°C to 2200 J/kg.K at 60°C. At temperatures above 25°C it is necessary to rerate polyethylene pipe systems. The table below provides guidance as to the maximum operating pressure of PE100 pipes. Below is a detailed table on Maximum Allowable Head (m) – PE100:

Temperature (°C)
Minimum Lifer (Years)
Design Factor
PN4
PN6.3
PN8
PN10
PN12.5
PN16
PN20
PN25
SDR41
SDR26
SDR21
SDR17
SDR13.6
SDR11
SDR9
SDR7.4
20
100
1.0
40
64
80
100
127
160
200
250
25
100
1.1
36
58
73
91
115
145
182
227
30
100
1.1
36
58
73
91
115
145
182
227
35
50
1.2
33
53
67
83
106
133
167
208
40
50
1.2
33
53
67
83
106
133
167
208
45
35
1.3
31
49
62
77
99
123
154
192
50
22
1.4
29
46
57
71
91
114
143
179
55
15
1.4
29
46
57
71
91
114
143
179
60
7
1.5
27
43
53
67
85
107
133
167
80
1
2.0
20
32
40
50
63
80
100
125
Temperature (°C)
Minimum Lifer (Years)
Design Factor
PN4
PN6.3
PN8
PN10
SDR41
SDR26
SDR21
SDR17
20
100
1.0
40
64
80
100
25
100
1.1
36
58
73
91
30
100
1.1
36
58
73
91
35
50
1.2
33
53
67
83
40
50
1.2
33
53
67
83
45
35
1.3
31
49
62
77
50
22
1.4
29
46
57
71
55
15
1.4
29
46
57
71
60
7
1.5
27
43
53
67
80
1
2.0
20
32
40
50
Temperature (°C)
Minimum Lifer (Years)
Design Factor
PN12.5
PN16
PN20
PN25
SDR13.6
SDR11
SDR9
SDR7.4
20
100
1.0
127
160
200
250
25
100
1.1
115
145
182
227
30
100
1.1
115
145
182
227
35
50
1.2
106
133
167
208
40
50
1.2
106
133
167
208
45
35
1.3
99
123
154
192
50
22
1.4
91
114
143
179
55
15
1.4
91
114
143
179
60
7
1.5
85
107
133
167
80
1
2.0
63
80
100
125
NOTE: The values tabled are for pipe manufactured to AS/NZS 4130 and fittings made from compounds complying with AS 4131. The minimum life periods may be considered to be the minimum potential service lives and represent the maximum extrapolated periods permitted by the ISO9080 extrapolation rules given the available test data. Maximum allowable operating pressure is indicated in metres head (1m = 9.81kPa).

Chemical Resistance

Polyethylene is in chemical terms a non-polar high molecular weight paraffin of the hydrocarbon family. Hence it is very resistant to (non-oxidising) strong acids, strong bases and salts. It is mildly affected by aliphatic solvents although aromatic and chlorinated solvents will cause some swelling. Polyethylene is attacked by strongly oxidising substances such as halogens and concentrated inorganic acids such as nitric, sulphuric (including oleum), perchloric etc.

Rural & Imperial Lines

Redline poly is made to AS 2698.2 dimensions and has a maximum operating pressure of 900 kPa. Greenline, 800 kPa poly pipe is for rural applications. Both Greenline and Redline pipes use rural compression range of fittings. Sizes range from 3/4 inch to 2 inch.

Buy : Arcbend™ Technology : Sweep Bends

Australian producers of quality, made-to-order long radius sweep bends in all pressure ratings, various diameters and angles of 90, 60, 45 and 30 degrees. Our sweep bends are specially engineered and designed to retain their shape and improve flow characteristics, thereby reducing wear and maintenance.

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