Standards

The performance of Polybutene-1 pipes

With its high resistance to creep over a wide temperature range coupled with low thermal expansion, Polybutene-1 has a particularly good fit with the industry requirements for pressure pipes use in domestic hot and cold water systems.
The internal pressure resistance of Polybutene-1 pipes is presented in ISO 12230 - Polybutene (PB) pipes: Effect of time and temperature on expected strength - which provides the benchmark for evaluating the suitability of all Polybutene-1 materials.
A graph of reference lines

This standard provides both a graph of reference lines and a table of hoop stress values, which together represent the criteria of acceptability specified in a number of other standards.

Expected Strength of Polybutene-1 (PB) Pipes Ref. ISO 12230
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Expected hoop strength values for various values of time and temperature

Temperature (°c) Time (years) Expected strength (MPa)
20 1
5
10
25
50
100		 14,5
14,3
14,2
13,9
13,6
13,4
30 1
5
10
25
50
100		 13,6
13,5
13,2
12,9
12,6
12,4
40 1
5
10
25
50
100		 12,7
12,4
12,1
11,8
11,5
11,2
50 1
5
10
25
50
100		 11,7
11,2
10,9
10,6
10,3
10
60 1
5
10
25
50		 10,6
9,9
9,6
9,2
9
70 1
5
10
25
50		 9,2
8,5
8,2
7,8
7,6
80 1
5
10
18
(25)		 7,6
6,9
6,7
6,4
(6,3)
90 1
4
6
(10)
(15)		 6
5,4
5,2
(5)
(4,9)
95 1
4
(6)
(10)		 5
4,5
(4,4)
(4,2)

The standard ISO 10508 - Thermoplastic pipes and fittings for hot and cold water systems - in combination with ISO 12230 defines the performance requirements in applications for which Polybutene-1 pipes can be used in terms of the following 'Classification of Service' conditions.ISO 10508 Thermoplastic Pipe Application Classes

Classification of Service Conditions for 50 Years
CEN/ISO Classes
Service Conditions
Class Application Normal Maximum Malfunction
    Temp
°C		 Time
years		 Temp
°C		 Time
years		 Temp
°C		 Time
hours
1 Hot Water Supply @ 60°C 60 49 80 1 95 100
2 Hot Water Supply @ 70°C 70 49 80 1 95 100
4 Underfloor Heating Low Temp. Heating Systems 40 20 70 2.5 100 100
60 25
5 High Temp. Heating Systems 60 25 90 1 100 100
80 10

Polybutene-1 Pipe Size Determination

Class S Value* S.D.R. (standard dimension ratio)
1 and 2511
36.313.6
4511
549

The most commonly used standard for determining the compliance of the performance of Polybutene-1 grades (with reference to ISO 12230) is ISO 9080 (EN) : Plastics piping and ducting systems - Determination of long-term hydrostatic strength of thermoplastics materials in pipe form by extrapolation.

This standard procedure is usually carried out by accredited pipe testing institutes to verify the performance of all thermoplastic hot and cold water pipe materials.

The evaluation of Basell's Polybutene-1 materials provided the following accredited results: