GB/T 2918-2018Plastics -- Standard atmospheres for conditioning and testing (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

This standard replaces GB/T 2918-1998 Plastics - Standard atmospheres for

conditioning and testing. Compared with GB/T 2918-1998, the main technical changes

except for editorial modifications are as follows:

-- Chapter 2 "2 Normative References" is added (see Chapter 2);

-- The use conditions of standard atmospheres at all levels such as "23/50 is

applicable to non-tropical regions, and 27/65 is applicable to tropical regions"

and the stipulation that "to obtain comparable data, the standard atmosphere of

23/50 shall be used" are added (see Chapter 5);

-- The calibration frequency is added (see Chapter 6);

-- The method for determining the sample conditioning time when equilibrium

cannot be reached for a long time is modified (see Appendix A).

This standard was redrafted and modified in relation to ISO 291:2008 Plastics -

Standard atmospheres for conditioning and testing.

The technical differences between this standard and ISO 291:2008 and their reasons are

as follows:

-- Regarding normative references, the adjustments with technical differences are

made in this standard to adapt to Chinese technical conditions. The adjustments

are concentrated in Chapter 2 "Normative references". The specific adjustments

are as follows:

 ISO 62 is replaced with GB/T 1034 which is identical to the international

standard;

-- The content of 8.1 NOTE 2 is modified into a paragraph;

-- The content of 8.1 NOTE 3 is modified into a paragraph.

This standard also made the following editorial changes.

-- The informative Appendix B "Background information" of ISO 291:2008 is

deleted;

-- References are deleted.

This standard was proposed by the China Petroleum and Chemical Industry Federation.

Plastics - Standard atmospheres for conditioning and testing

1 Scope

This standard specifies the specifications for conditioning and testing plastics and all

types of specimens under constant environmental conditions.

This standard applies to plastics and all types of specimens.

This standard does not include special environments for certain special tests or materials

or for simulating certain specific climatic conditions.

2 Normative references

The following documents are essential for the application of this document. For any

dated referenced document, only the dated version applies to this document. For any

undated referenced document, the latest version (including all amendments) applies to

this document.

GB/T 1034 Plastics - Determination of water absorption (GB/T 1034-2008, ISO

62:2008, IDT)

3 Terms and definitions

The following terms and definitions apply to this document.

8 Operation steps