GB/T 8811-2008Test method for dimensional stability of rigid cellular plastics (English PDF)

Foreword

This standard identically adopts ISO 2796.1986 "Cellular plastics, rigid - Test for

dimensional stability".

This standard makes only the following editorial modifications to ISO 2796.1986.

- ADJUST the order of some clauses in Article 7.3 "Test procedures";

- DELETE the statements regarding precision and accuracy in ISO 2796.1986.

This standard is a revision of GB/T 8811-1988 "Rigid cellular plastics - Test method

for dimensional stability".

The main differences between this standard and GB/T 8811-1988 are as follows.

- ADD the foreword;

- ADD the terms and definitions;

- SPECIFY that the given specimen size is the minimum size;

- CHANGE the placement time of the specimen after removal from the selected test

conditions from 1 hour to 1 ~ 3 hours;

- ADD the information on the "Arithmetic mean of the rate of dimensional change"

to the test report.

This standard replaces GB/T 8811-1988, from the date of its implementation.

This standard was proposed by the China National Light Industry Council.

This standard shall be under the jurisdiction of the National Technical Committee on

Standardization of Plastics Products.

The drafting organizations of this standard. Beijing Plastics Research Institute, Beijing

Technology and Business University.

1 Scope

This standard specifies a method for determining the dimensional stability of rigid

cellular plastics under specific temperature and relative humidity conditions.

This standard is applicable to the determination of the dimensional stability of rigid

cellular plastics.

2 Normative references

The provisions in following documents become the provisions of this Standard through

reference in this Standard. For the dated references, the subsequent amendments

(excluding corrections) or revisions do not apply to this Standard; however, parties who

reach an agreement based on this Standard are encouraged to study if the latest versions

of these documents are applicable. For undated references, the latest edition of the

referenced document applies.

GB/T 2918-1998 Plastics - Standard atmospheres for conditioning and testing (idt

ISO 291.1997)

GB/T 6342-1996 Cellular plastics and rubbers - Determination of linear dimensions

(idt ISO 1923.1981)

3 Terms and definitions

The following terms and definitions apply to this standard.

3.1

Dimensional stability

The irreversible dimensional change in three mutually perpendicular directions that

occurs after a specimen has been placed under specific temperature and relative

humidity conditions for a certain period of time.

4 Principle

The change in linear dimensions of a specimen is measured, after it has been placed

under specified test conditions for a certain period of time and conditioned under a

standard environment.

5 Instruments

6 Specimens and preparation

7 Test methods