GB/T 15560-1995 English PDF (GBT15560-1995)

Delivery: 3 seconds. Download true-PDF + Invoice.
Get QUOTATION in 1-minute: Click GB/T 15560-1995
Historical versions: GB/T 15560-1995
Preview True-PDF (Reload/Scroll if blank)

GB/T 15560-1995: Standard test method for short-time hydraulic failure and resistance to constant internal pressure of the plastics pipes for the transport of fluids
GB/T 15560-1995
GB
NATIONAL STANDARD OF THE
PEOPLE'S REPUBLIC OF CHINA
Standard test method for short-time hydraulic failure and
resistance to constant internal pressure of the plastics pipes
for the transport of fluids
ISSUED ON: MAY 2, 1995
IMPLEMENTED ON: DECEMBER 1, 1995
Issued by: State Bureau of Quality and Technical Supervision
Table of Contents
1 Subject contents and application scope ... 3
2 Normative references ... 3
3 Terminology ... 3
4 Test principle ... 4
5 Sealing joints ... 4
6 Test equipment ... 4
7 Specimens ... 5
8 Test conditions and pretreatment ... 5
9 Test steps ... 6
10 Calculation ... 7
11 Test report ... 7
Appendix A Sealing joints (Informative) ... 8
Appendix B Gas pressurization system (Informative) ... 11
Additional information ... 11
Standard test method for short-time hydraulic failure and
resistance to constant internal pressure of the plastics pipes
for the transport of fluids
1 Subject contents and application scope
This standard specifies test methods for short-time hydraulic failure and resistance to
pressure of the plastic pipes for fluid transportation.
This standard is applicable to various types of thermoplastic pipes and thermosetting-
reinforced plastic pipes for fluid transportation.
2 Normative references
GB 8806 Plastics piping systems - Plastics components - Determination of
dimensions
3 Terminology
3.1 Failure: It refers to the continuous loss of pressure through the liquid in the sample.
Failure can be one of the following forms or a combination of the following forms.
a. Ductile failure: It refers to the rupture of the specimen accompanied by plastic
deformation or local spherical expansion.
NOTE: The slight expansion of the specimen due to creep caused by long-term stress does
not belong to ductile failure.
b. Brittle failure: It means that there is no obvious material deformation in the
fracture area of the specimen, such as extension and necking; at this time, the
test pressure does not show a yielding phenomenon, the specimen ruptures
instantly, and the pressure drops rapidly to zero.
c. Leakage and seepage: It refers to the liquid in the specimen seeping out
through the tiny cracks in the pipe wall under the action of pressure. If the test
pressure is reduced at this time, the pipe specimen will usually not experience
liquid loss.
4 Test principle
This test method is divided into two test types: the short-time failure test and the
resistance to pressure test.
The short-time failure test refers to the rapid and continuous application of liquid
pressure to the interior of a given section of the plastic pipe specimen, causing the
specimen to rupture in a short period of time. The pressure value when the specimen
ruptures is read and its hoop stress is calculated.
The resistance to pressure test is to subject a given section of plastic pipe specimen to
a specified constant internal pressure for a given period of time and observe whether
the specimen is damaged. The test pressure value and test time are determined by the
product standard of the pipe.
5 Sealing joints
Sealing joints are installed at both ends of the specimen. The joints are reasonably
designed to seal the specimen and the pressure device. The joints installed on the
specimen cannot cause the specimen to bear axial force or cause damage to the
specimen.
It is recommended to use the sealing joints in Appendix A (informative).
6 Test equipment
6.1 Constant temperature control system
The constant temperature system consists of a constant temperature bath, a fluid
circulation or stirring device, a heating and temperature control device, etc. Regardless
of whether the heating medium in the constant temperature bath is water, air or other
fluids, the temperature is maintained within a deviation of ±2 °C.
6.2 Pressure system
6.2.1 The pressure-applying device is required to gradually and steadily raise the
pressure to the specified value, and then maintain the pressure within a deviation of ±2%
throughout the test.
6.2.2 For the short-time failure test, the pressure device is required to have sufficient
pressure capacity to complete the specimen rupture within 60~70 seconds. It is
recommended to use the gas pressurization system shown in Appendix B (informative).
6.2.3 The pressure system can apply pressure to a single specimen or to multiple
specimens simultaneously through a system branch. In the case of a system branch,
each pressure branch is required to have a controllable shut-off valve and each specimen
branch has its own pressure gauge.
When a specimen ruptures, the pressure control system can close the branch to prevent
the pressure of specimens on other branches from dropping (it is recommended to use
an electric-contact pressure gauge for control or similar pressure control systems).
6.3 Pressure gauge
6.3.1 The accuracy of the test pressure gauge shall not be lower than Grade 1.0.
6.3.2 The range scale of the pressure gauge shall be selected so that the pressure value
reading is around 60% of the pressure gauge scale. Each specimen is required to have
a pressure gauge, and the pressure gauge shall be equipped with a pressure buffer
protection device.
6.4 Timing device
The timer is accurate to within ±2%.
7 Specimens
7.1 The surface of the specimen shall not have visible cracks, scratches or other defects
that affect the test results. Both ends of the specimen shall be flat and perpendicular to
the axis of the pipe.
7.2 Specimen length: Unless otherwise specified in the product standard, the effective
length L of the specimen between two sealed joints shall comply with the requirements
of the following table.
Nominal outer diameter D< 160 mm L=5D, but not less than 300 mm
Nominal outer diameter D≥160 mm L=3D, but not less than 760 mm
7.3 Number of specimens
Under the same test conditions, the number of specimens shall not be less than 5. Or,
the number of specimens shall be determined according to the provisions of the product
standard.
8 Test conditions and pretreatment
8.1 The test temperature shall be in accordance with the test conditions specified in the
product standards.
8.2 Liquid pressure must be applied inside the specimen, such as water. If other media
are used, it must be ensured that the liquid does not corrode the specimen.
8.3 The environment outside the specimen can be a liquid or gas environment. The
temperature of the external environment must be the same as the temperature of the
liquid inside the specimen.
8.4 The specimen shall be pretreated before pressure is applied. The pretreatment
temperature shall be the same as the test temperature. The pretreatment time shall be
such that the specimen reaches the test temperature. For the test at 23 °C, when the
specimen is immersed in liquid, the pretreatment time shall be not less than 1 h. When
the specimen is placed in a gas medium, the pretreatment time shall be not less than 16
h.
9 Test steps
9.1 Install the sealing joints on the specimens. Fill each specimen with liquid at the test
temperature, remove the air from the specimen, and then pretreat it according to 8.4.
9.2 Connect the specimen to the pressure device and support the specimen to prevent
bending and deflection of the specimen due to the weight of the pipe and joints (the
support shall not cause longitudinal and radial constraints on the specimen).
9.3 Apply test pressu...