GB/T 451.2-2023 English PDF (GB/T451.2-2023)

GB/T 451.2-2023: Paper and board - Part 2: Determination of grammage
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GB/T 451.2-2023
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 85.060
CCS Y 32
Replacing GB/T 451.2-2002
Paper and Board – Part 2: Determination of Grammage
(ISO 536:2019, Paper and Board – Determination of Grammage, MOD)
ISSUED ON: DECEMBER 28, 2023
IMPLEMENTED ON: JULY 1, 2024
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
Introduction ... 6
1 Scope ... 7
2 Normative References ... 7
3 Terms and Definitions... 7
4 Principle ... 8
5 Instruments ... 8
6 Sampling ... 8
7 Specimen Treatment ... 9
8 Test Procedures ... 9
9 Expression of Results ... 9
10 Test Report ... 11
Appendix A (Informative) Comparison of Structure Numbers between This Document
and ISO 536:2019 ... 12
Appendix B (Normative) Determination of Oven-Dry Grammage and As-Taken
Grammage ... 13
Foreword
This Document was drafted as per the rules specified in GB/T 1.1-2020 Directives for
Standardization – Part 1: Rules for the Structure and Drafting of Standardizing Documents.
This Document is Part 2 of GB/T 451. GB/T 451 consists of the following parts:
--- Paper and Board – Determination of Size and Deviation (GB/T 451.1);
--- Part and Board – Determination of Grammage (GB/T 451.2);
--- Paper and Board – Determination of Thickness (GB/T 451.3).
This Document replaced GB/T 451.2-2002 Part and Board – Determination of Grammage.
Compared with GB/T 451.2-2002, the major technical changes of this Document are as follows
besides the structural adjustments and editorial modifications:
a) Add the terms and definitions of "oven-dry grammage" and "as-taken grammage" (see
Clause 3 of this Edition);
b) Change the calculation method of the area when the cutting area of the sample cutting
equipment reaches the accuracy (see 5.1 of this Edition, 5.1 of the 2002 edition); add the
accuracy requirements for the measurement size of each specimen when the cutting area
accuracy of the sample cutting equipment does not reach the specified requirements (see
5.1 of this Edition);
c) Delete the instrument calibration (see 5.3 of the 2002 Edition);
d) Add paper and board grammage determination instruments and drying ovens (see 5.3 and
5.4 of this Edition);
e) Change sampling quantity of the sample (see Clause 6 of this Edition; Clause 6 of the
2002 Edition); and add the sampling requirements for as-taken grammage determination
(see Clause 6 of this Edition);
f) Change the description of the standard operation when the available sample area is limited
(see 8.1 of this Edition; 8.1 of the 2002 Edition);
g) Add grammage calculation using paper and board grammage tester (see 9.2 of this
Edition);
h) Add calculation of grammage deviation (see 9.3 of this Edition);
i) Change test report (see Clause 10 of this Edition; Clause 10 of the 2002 Edition);
j) Add determination of oven-dry grammage and as-taken grammage (see Appendix B of
Paper and Board – Part 2: Determination of Grammage
1 Scope
This Document describes the determination method of grammage of paper and board.
This Document applies to the determination of grammage of paper and board.
2 Normative References
The provisions in following documents become the essential provisions of this Document
through reference in this Document. For the dated documents, only the versions with the dates
indicated are applicable to this Document; for the undated documents, only the latest version
(including all the amendments) is applicable to this Document.
GB/T 450 Paper and board - Sampling for testing and identification of machine and cross
direction wire side and felt side (GB/T 450-2008, ISO 186:2002, MOD)
GB/T 462 Paper, board and pulps - Determination of moisture content of analytical sample
(GB/T 462-2023, ISO 287:2017, ISO 638-1:2022, ISO 638-2:2022, MOD)
GB/T 10739 Paper, board and pulps - Standard atmosphere for conditioning and testing
(GB/T 10739-2023, ISO 187:2022, MOD)
3 Terms and Definitions
For the purposes of this Document, the following terms and definitions apply.
3.1 Grammage
The mass per unit area of paper and board measured by the specified test method.
NOTE: The grammage is expressed in grams per square meter (g/m2).
3.2 Oven-dry grammage
The mass per unit area of paper and board measured when dried to constant weight at 105 ℃ ±
2 ℃.
3.3 As-taken grammage
be at least enough to cut 20 pieces of specimens.
If the as-taken grammage is required to be determined, the influence of the environment on the
moisture content of the specimen shall be minimized (see B.2).
7 Specimen Treatment
When determining the grammage and oven-dry grammage, the specimen treatment and the
standard atmospheric conditions of the test shall be carried out in accordance with the
provisions of GB/T 10739.
8 Test Procedures
8.1 Determination of grammage
Take any sample, use the sample cutting device (5.1) to evenly cut 4 pieces of specimens of
0.01m2 along the horizontal direction of the sample; and cut a total of 20 pieces of specimens
from the 5 samples according to the above method. If necessary, smaller test pieces can be
combined to reach the specified total area of specimen (0.20m2).
If the sample area is limited and the specified total area of specimen cannot be met, a specimen
with a total area of no less than 0.05 m2 shall be used; and the measurement area of the specimen
shall be noted in the test report.
Weigh the mass of the specimen on a balance (5.2) or a paper and board grammage measuring
instrument (5.3).
When treating the small specimens, the specimens shall not be touched with bare hands.
8.2 Determination of oven-dry grammage or as-taken grammage
The oven-dry grammage and as-taken grammage shall be determined according to Appendix B.
8.3 Determination of horizontal grammage difference
Randomly select a whole sheet of paper, cut at least 5 pieces of specimens of 0.01 m2 uniformly
along the horizontal direction of the paper; weigh them separately with a balance; and calculate
the grammage of each piece.
9 Expression of Results
9.1 When weighing a specimen by a balance, the specimen grammage shall be calculated
according to Formula (1) and the result shall be rounded-off to three significant figures.
GB/T 451.2-2023
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 85.060
CCS Y 32
Replacing GB/T 451.2-2002
Paper and Board – Part 2: Determination of Grammage
(ISO 536:2019, Paper and Board – Determination of Grammage, MOD)
ISSUED ON: DECEMBER 28, 2023
IMPLEMENTED ON: JULY 1, 2024
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
Introduction ... 6
1 Scope ... 7
2 Normative References ... 7
3 Terms and Definitions... 7
4 Principle ... 8
5 Instruments ... 8
6 Sampling ... 8
7 Specimen Treatment ... 9
8 Test Procedures ... 9
9 Expression of Results ... 9
10 Test Report ... 11
Appendix A (Informative) Comparison of Structure Numbers between This Document
and ISO 536:2019 ... 12
Appendix B (Normative) Determination of Oven-Dry Grammage and As-Taken
Grammage ... 13
Foreword
This Document was drafted as per the rules specified in GB/T 1.1-2020 Directives for
Standardization – Part 1: Rules for the Structure and Drafting of Standardizing Documents.
This Document is Part 2 of GB/T 451. GB/T 451 consists of the following parts:
--- Paper and Board – Determination of Size and Deviation (GB/T 451.1);
--- Part and Board – Determination of Grammage (GB/T 451.2);
--- Paper and Board – Determination of Thickness (GB/T 451.3).
This Document replaced GB/T 451.2-2002 Part and Board – Determination of Grammage.
Compared with GB/T 451.2-2002, the major technical changes of this Document are as follows
besides the structural adjustments and editorial modifications:
a) Add the terms and definitions of "oven-dry grammage" and "as-taken grammage" (see
Clause 3 of this Edition);
b) Change the calculation method of the area when the cutting area of the sample cutting
equipment reaches the accuracy (see 5.1 of this Edition, 5.1 of the 2002 edition); add the
accuracy requirements for the measurement size of each specimen when the cutting area
accuracy of the sample cutting equipment does not reach the specified requirements (see
5.1 of this Edition);
c) Delete the instrument calibration (see 5.3 of the 2002 Edition);
d) Add paper and board grammage determination instruments and drying ovens (see 5.3 and
5.4 of this Edition);
e) Change sampling quantity of the sample (see Clause 6 of this Edition; Clause 6 of the
2002 Edition); and add the sampling requirements for as-taken grammage determination
(see Clause 6 of this Edition);
f) Change the description of the standard operation when the available sample area is limited
(see 8.1 of this Edition; 8.1 of the 2002 Edition);
g) Add grammage calculation using paper and board grammage tester (see 9.2 of this
Edition);
h) Add calculation of grammage deviation (see 9.3 of this Edition);
i) Change test report (see Clause 10 of this Edition; Clause 10 of the 2002 Edition);
j) Add determination of oven-dry grammage and as-taken grammage (see Appendix B of
Paper and Board – Part 2: Determination of Grammage
1 Scope
This Document describes the determination method of grammage of paper and board.
This Document applies to the determination of grammage of paper and board.
2 Normative References
The provisions in following documents become the essential provisions of this Document
through reference in this Document. For the dated documents, only the versions with the dates
indicated are applicable to this Document; for the undated documents, only the latest version
(including all the amendments) is applicable to this Document.
GB/T 450 Paper and board - Sampling for testing and identification of machine and cross
direction wire side and felt side (GB/T 450-2008, ISO 186:2002, MOD)
GB/T 462 Paper, board and pulps - Determination of moisture content of analytical sample
(GB/T 462-2023, ISO 287:2017, ISO 638-1:2022, ISO 638-2:2022, MOD)
GB/T 10739 Paper, board and pulps - Standard atmosphere for conditioning and testing
(GB/T 10739-2023, ISO 187:2022, MOD)
3 Terms and Definitions
For the purposes of this Document, the following terms and definitions apply.
3.1 Grammage
The mass per unit area of paper and board measured by the specified test method.
NOTE: The grammage is expressed in grams per square meter (g/m2).
3.2 Oven-dry grammage
The mass per unit area of paper and board measured when dried to constant weight at 105 ℃ ±
2 ℃.
3.3 As-taken grammage
be at least enough to cut 20 pieces of specimens.
If the as-taken grammage is required to be determined, the influence of the environment on the
moisture content of the specimen shall be minimized (see B.2).
7 Specimen Treatment
When determining the grammage and oven-dry grammage, the specimen treatment and the
standard atmospheric conditions of the test shall be carried out in accordance with the
provisions of GB/T 10739.
8 Test Procedures
8.1 Determination of grammage
Take any sample, use the sample cutting device (5.1) to evenly cut 4 pieces of specimens of
0.01m2 along the horizontal direction of the sample; and cut a total of 20 pieces of specimens
from the 5 samples according to the above method. If necessary, smaller test pieces can be
combined to reach the specified total area of specimen (0.20m2).
If the sample area is limited and the specified total area of specimen cannot be met, a specimen
with a total area of no less than 0.05 m2 shall be used; and the measurement area of the specimen
shall be noted in the test report.
Weigh the mass of the specimen on a balance (5.2) or a paper and board grammage measuring
instrument (5.3).
When treating the small specimens, the specimens shall not be touched with bare hands.
8.2 Determination of oven-dry grammage or as-taken grammage
The oven-dry grammage and as-taken grammage shall be determined according to Appendix B.
8.3 Determination of horizontal grammage difference
Randomly select a whole sheet of paper, cut at least 5 pieces of specimens of 0.01 m2 uniformly
along the horizontal direction of the paper; weigh them separately with a balance; and calculate
the grammage of each piece.
9 Expression of Results
9.1 When weighing a specimen by a balance, the specimen grammage shall be calculated
according to Formula (1) and the result shall be rounded-off to three significant figures.