Skip to product information
1 of 10

PayPal, credit cards. Download editable-PDF and invoice in 1 second!

GB/T 458-2008 English PDF (GBT458-2008)

GB/T 458-2008 English PDF (GBT458-2008)

Regular price $85.00 USD
Regular price Sale price $85.00 USD
Sale Sold out
Shipping calculated at checkout.
Quotation: In 1-minute, 24-hr self-service. Click here GB/T 458-2008 to get it for Purchase Approval, Bank TT...

GB/T 458-2008: Paper and board -- Determination of air permeance

This standard specifies three methods for the measurement of air permeance of paper and board: Gurley method, Schopper method, and Bendtsen method.
GB/T 458-2008
GB
NATIONAL STANDARD
OF THE PEOPLE REPUBLIC OF CHINA
ICS 85-010
Y 30
Replacing GB/T 5402-2003, GB/T 2679.13-1996, GB/T 458-2002
Paper and board - Measurement of air permeance
[ISO 5636-2.1984, Paper and board - Measurement of air permeance (medium range) - Part 2. Schopper method; ISO 5636-3.1992, Paper and board -
Measurement of air permeance (medium range) - Part 3. Bendtsen method;
ISO 5636-5.2003, Paper and board - Measurement of air permeance and air resistance (medium range) - Part 5. Gurley method, MOD]
ISSUED ON. AUGUST 19, 2008
IMPLEMENTED ON. MAY 01, 2009
Issued by. General Administration of Quality Supervision, Inspection and Quarantine;
Standardization Administration of PRC.
Table of contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 Measurement procedures of Gurley method ... 6
5 Measurement procedures of Schopper method ... 8
6 Measurement procedures of Bendtsen method ... 10
7 Test report ... 11
APPENDIX A (Normative) Gurley air permeance tester ... 13
APPENDIX B (Normative) Schopper air permeance tester ... 16
Appendix C (Normative) Bendtsen air permeance tester ... 17
Foreword
This standard, through modification, adopts ISO 5636-2.1984, Paper and
board - Measurement of air permeance (medium range) - Part 2. Schopper
method; ISO 5636-5.2003, Paper and board - Measurement of air permeance and air resistance (medium range) - Part 5. Gurley method; AND ISO
5636-3.1992, Paper and board - Measurement of air permeance (medium
range) - Part 3. Bendtsen method.
As compared with ISO 5636-2.1984, ISO 5636-3.1992 and ISO 5636-5.2003,
the main differences are as follows.
- DELETE the introduction from international standards;
- CONSOLIDATE the scope of international standards;
- MOVE the instrument description in this standard into Appendix.
This standard the integration and modification of GB/T 458-2002 ?€?Paper and board - Measurement of air permeance (Schopper method)?€?, GB/T
2679.13-1996 ?€?Paper and board - Measurement of air permeance (medium
range) - Bendtsen method?€? and GB/T 5402-2003 ?€?Paper and board -
Measurement of air permeance and air resistance (medium range) - Gurley method?€?, AND it replaces the above three standards.
Compared with GB/T 458-2002, GB/T 2679.13-1996 and GB/T 5402-2003, this standard has the following changes.
- INTRODUCE the instrument structure and working principle in the form of an appendix, in order to facilitate the rationality of the main contents of this standard;
- In the Gurley method, DELETE the splint above type instrument because it is out of date, and DELETE accordingly the relevant standard contents;
so the party using this standard please pay attention to the relevant
changes.
Appendix A, Appendix B and Appendix C of this Standard are normative
appendixes.
This standard was proposed by China Light Industry Association.
This standard shall be under the jurisdiction of the National Paper Industry Standardization Technical Committee.
Paper and board - Measurement of air permeance
1 Scope
This standard specifies three methods for the measurement of air permeance of paper and board. Gurley method, Schopper method, and Bendtsen method. This standard is applicable to paper and board with air permeance between 1 ?? 10-2??m / (Pa ?€? s) ~ 1 ?? 102??m / (Pa ?€? s).
This standard does not apply to paper and board with a large surface
roughness which cannot be firmly clamped, such as crepe paper or corrugated paperboard.
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 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 10739 Paper, board and pulps - Standard atmosphere for conditioning and testing (GB/T 10739-2002, eqv ISO 187.1990)
3 Terms and definitions
The following terms and definitions apply to this standard.
3.1
Air permeance
It refers to, based on the specified conditions at the unit time and unit pressure difference, the mean air flow passing through the unit area paper or board, expressed in microns per Pascal seconds [1 ??m / (Pa ?€? s) = 1 mL / (m2 ?€? Pa ?€? s)].
4 Measurement procedures of Gurley method
4.1 Preparation of test specimens
4.1.1 The sample shall be taken in accordance with GB/T 450.
4.1.2 The temperature and humidity treatment for sample shall be conducted in accordance with the provisions of GB/T 10739.
4.1.3 From 10 samples, respectively CUT one specimen of the size 50 mm ?? 50 mm.
Note. The measurement surface shall not have wrinkles, cracks, holes or other appearance defects.
4.2 Measurement
4.2.1 The measurement shall be conducted under the same atmospheric
conditions as those used in the temperature and humidity treatment.
4.2.2 ADJUST the instrument to the horizontal position so that the two
cylinders are in a vertical position; and then CLAMP the smooth, hard, dense, and impermeable metal or plastic sheet in between the two pore plates, to check the tightness of the instrument. In accordance with 4.2.3, CONDUCT inspection; after measurement for 5 h, the leaked air shall not be greater than 50 mL.
4.2.3 RAISE the inner cylinder so that its edge is on the support of the outer cylinder. CLAMP the specimen; REMOVE the supporting device, in order to lower down the inner cylinder to the position that can be floated.
When the inner cylinder is steadily lowered, START time keeping from the zero scale, and MEASURE the time required by the initial two 50 mL interval (i.e., the interval from 0 mL to 100 mL) to pass the outer cylinder edge.
??? 60 s. accurate to 0.2 s;
> 60 s to ??? 180 s. accurate to 1 s;
> 180 s. accurate to 5 s.
??p - Pressure difference between the two sides of the sample, in kilopascal (kPa);
t - Measurement time, in seconds (s).
5.4 Precision
TAKE two specimens from the same sample; ARRANGE one operator to
conduct measurement in the same lab; AND the deviation of the mean values of the two measurement results shall be within 10%.
6 Measurement procedures of Bendtsen method
6.1 Preparation of test specimens
6.1.1 The sample shall be taken in accordance with GB/T 450.
6.1.2 The temperature and humidity treatment for sample shall be conducted in accordance with the provisions of GB/T 10739.
6.1.3 From 10 samples, respectively CUT one specimen of the size 50 mm ?? 50 mm.
Note. The measurement surface shall not have wrinkles, cracks, holes or other appearance defects.
6.2 Measurement
6.2.1 The measurement shall be conducted under the same atmospheric
conditions as those used in the temperature and humidity treatment.
6.2.2 PLACE the instrument on a stable workbench and ADJUST it level.
6.2.3 Based on the test sample, SELECT appropriate flow meter and working pressure (the pressure as specified in this standard is 1.47 kPa).
6.2.4 After completing the leakage inspection and flow rate calibration, CONNECT the flowmeter and measurement probe.
6.2.5 CLAMP the sample in between the annular plate and the gasket; and RECORD the flowmeter reading 5 s after clamping.
6.2.6 CONDUCT measurement on the front of 5 samples and back of another five samples. If there is a significant difference in the air permeance through the front side and the back side, AND meanwhile it is required to report such APPENDIX A
(Normative)
Gurley air permeance tester
A.1 Instrument
The instrument consists of an outer cylinder and an inner cylinder. The outer cylinder contains a certain amount of sealing liquid, AND the inner cylinder is free to slide in the outer cylinder. The outer cylinder has a height of 254 mm and an inner diameter of 82.6 mm, in which 3 or 4 metal strips are arranged erectly on the inner wall at same interval. The length of the metal strip is between 190 mm and 245.5 mm, AND the cross section of the metal strip is square of edge length 2.4 mm OR circle of diameter 2.4 mm; the metal strip is used as the guide rail for the movement up and down of the inner cylinder. The inner cylinder has a height of 254 mm, an outer diameter of 76.2 mm, an inner diameter of 74.1 mm and a mass of (567 ?? 0.5) g. The air pressure formed by the self-gravity of the inner cylinder is applied to a sample sandwiched between the plates having an aperture of (28.6 ?? 0.1) mm.
The splint is located at the base, AND at the splint side with air pressure is attached with a rubber liner, in order to avoid air leakage between the sample surface and the splint. The liner is made from thin, resilient, oil resistant, and oxidation resistant materials, AND has smooth and flat surfaces. The thickness of the liner is 0.7...

View full details