GB/T 19472.2-2017Polyethylene structure-wall piping systems for underground usage—Part2: Polyethylene spirally enwound structure-wall pipes (English PDF)

3.1 Terms and definitions

Terms and definitions determined by GB/T 19278-2003, and the following ones are applicable to this document.

3.1.1 Spirally enwound structure-wall pipes

Pipes made by using the filament winding process, with polyolefin material as an auxiliary support structure.

3.1.7 Mean inside diameter

Arithmetic mean of two or more measured values of inside diameter that are perpendicular to each other.

Note: Rewrite definition 3.11 in GB/T 19278-2003.

3.1.8 Wall thickness

The wall thickness measured at any point on the circumference of the pipe or fitting.

3.1.9 Structure height

Radial distance between the inner and outer surfaces of the pipe wall (type A structure-wall pipes), or between the inner surface of the pipe wall and the top of the rib (type B or type C structure-wall pipes).

3.1.10 Inner wall thickness

The wall thickness at any point between the spiral O-shaped ribs of type B and type C pipes and fittings.

3.1.11 Inner wall of the cavity part thickness

The wall thickness between the lower inner wall and the inner surface of any cavity part of type A pipes and fittings.

3.2 Symbols

The following symbols apply to this document.

3.3 Abbreviated terms

For the purposes of this document, the following abbreviated terms apply.

5.1 Pipe classification

5.1.1 Pipes classified by nominal ring stiffness grade

The nominal ring stiffness of pipes is divided into 6 grades, as shown in Table 2.

5.1.2 Pipes classified by structure types

Pipes are divided into type A, type B and type C according to their structure types, as shown in 6.1.

5.2 Pipe identification

Pipes are identified as follows.

6.1 Structure types of pipes

6.1.1 Type A structure-wall pipes

6.1.1.1 Pipes with flat inner and outer surfaces and made of polyethylene materials spirally welded between preformed polyethylene square pipes. Typical example 1 is shown in Figure 1.

6.1.1.2 On the preheated integral steel drum mold, use the filament-wound and processed pipes whose inner surface is smooth and flat, outer surface is flat, and pipe wall is embedded with spirally wound O-shaped polyolefin material (generally polypropylene) as auxiliary supports for hollow pipes.

6.1.2 Type B structure-wall pipes

On the preheated integral steel drum mold, use the filament-wound and processed pipes whose inner surface is smooth and flat and outer surface is spiral O-shaped ribs. And the O-shaped rib of the pipe shall have a hollow pipe with polyolefin material (usually polypropylene) as auxiliary support.

6.1.3 Type C structure-wall pipes

On multiple rollers in the cold state, use the continuously wound and processed pipes whose inner surface has a contour of slight peaks and troughs, and the outer surface is spiral O-shaped ribs.

7.1 Color

The color of pipes and pipe fittings is generally black, and other colors are determined by negotiation between the supply and demand parties.

7.2 Appearance

7.2.1 The inner and outer surfaces of pipes and pipe fittings in typical example 1 of type A structure-wall pipes shall be flat.

7.3 Dimensions

7.3.1 Length

The effective length L of the pipe is generally 6 m, and other lengths are agreed upon by both parties. There shall be no negative deviation in the effective length of the pipe.

7.4 Physical and mechanical properties

7.4.1 Physical properties of pipes

The physical properties of pipes shall meet the requirements of Table 6.

7.4.2 Mechanical properties of pipes

The mechanical properties of pipes shall comply with the requirements in Table 7.

8.1 Pre-conditioning of samples

Unless otherwise specified, the samples shall be conditioned and tested in accordance with the provisions of GB/T 2918-1998 at 23 °C ± 2 °C.

8.2 Color and appearance

By visual inspection, the interior can be illuminated by a light source.

8.3 Dimensions

8.4 Longitudinal retraction rate

Conduct the test according to method B specified in GB/T 6671-2001. Cut three sections of samples from different parts of a pipe, with a length of 200 mm ± 20 mm.

In case of pipe DN/ID < 400 mm, it can be cut into two test blocks of the same size along the axial direction; in case of pipe DN/ID >= 400 mm, it can be cut into 4 (or more) test blocks of the same size along the axial direction.

8.5 Oven test

8.6 Ash

Conduct the test according to GB/T 9345.1-2008. Use the direct calcination method.

The sampling location is any place on the inner, outer wall or spigot end of the pipe (excluding auxiliary support structures).

8.7 Oxidation induction time

Conduct the test according to GB/T 19466.6-2009. Samples shall be taken from the inner and outer walls of the pipe (excluding auxiliary support structures), with the original surface facing upwards for testing. The number of samples is 3, and the test result is the minimum value.

8.10 Impact performance

8.10.1 Conduct the test according to GB/T 14152-2001. The test temperature is 0 °C ± 1 °C; the hammer model is d 90; the mass and impact height of the hammer are shown in Table 10.

8.14 System suitability

8.14.1 Sealing property of elastomeric sealing elements

Follow the provisions of Appendix E. See Table 9 for the test parameters.

8.14.2 Tensile force of welded connections

Conduct the test according to GB/T 8804.3-2003. Prepare the samples according to Figure D.2 in Appendix D.

9.1 Batch

Pipes and pipe fittings of the same specifications produced with the same raw materials, formulas and processes are considered to be one batch. When pipes and pipe fittings DN/ID <= 500 mm, the quantity per batch shall not exceed 60 t.

9.3 Exit-factory inspection

9.3.1 The ex-factory inspection items are the items specified in 7.1 ~ 7.3, and the ash content, oxidation induction time, density, ring stiffness, ring flexibility and tensile force test at the welding point in 7.4.

9.4 Type inspection

9.4.1 Type inspection items are all items required by the technical requirements in Chapter 7.

9.4.2 Select pipes and pipe fittings of any specification from the size groups specified in 9.2, and inspect items 7.1 ~ 7.3 according to the provisions of 9.3.2. Among the pipes and pipe fittings that pass the inspection, randomly select a sample and conduct each test in 7.4 ~ 7.5. Generally, type inspection is conducted every three years. If one of the following situations occurs, type inspection shall be carried out.

9.5 Determination rules

Items 7.1 ~ 7.3 are determined according to Table 12. […]