GB/T 4745-2012 English PDF (GBT4745-2012)

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GB/T 4745-2012: Textiles -- Testing and evaluation for water resistance -- Spray test method
GB/T 4745-2012
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 59.080.30
W 04
Replacing GB/T 4745-1997
Textiles - Testing and evaluation for water resistance -
Spray test method
[ISO 4920:2012, Textiles fabrics - Determination of resistance to surface
wetting (spray test), MOD]
ISSUED ON: DECEMBER 31, 2012
IMPLEMENTED ON: JUNE 01, 2013
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 Principle ... 6 
5 Apparatus and materials ... 6 
6 Atmosphere for humidity control and test ... 8 
7 Specimen ... 8 
8 Steps ... 8 
9 Results and evaluation ... 9 
10 Test report ... 10 
Appendix A (Normative) Image rating ... 11 
Foreword
This standard was drafted in accordance with the rules given in GB/T 1.1-2009
and GB/T 20000.2-2009.
This standard replaces GB/T 4745-1997 "Textiles - Testing and evaluation for
water resistance - Spray test method". Compared with GB/T 4745-1997, this
standard has the following main differences:
- MODIFY the standard name;
- ADD two terms: water resistance and face (see 3.1 and 3.3);
- ADD the tolerance of specific parameters in the test device (see 5.1, 5.2,
5.3);
- REFINE the spray rating to half level (see 9.1);
- ADD water resistance evaluation (see 9.2);
- In Appendix A, ADD the images and corresponding descriptions of level 0
(see Appendix A).
This standard uses the redrafting method to amend and adopt ISO 4920:2012
"Textiles fabrics - Determination of resistance to surface wetting (spray test)".
Compared with ISO 4920:2012, the main differences between this standard are
as follows:
- MODIFY the standard name;
- ADD the term of water resistance (see 3.1);
- REFINE the spray rating to half level (see 9.1);
- ADD the water resistance evaluation (see 9.2);
- In Appendix A, ADD the corresponding relationship between GB and ISO
spray rating.
This standard was proposed by the China National Textile and Apparel Council.
This standard shall be under the jurisdiction of the Basic Standards
Subcommittee of the National Textile Standardization Technical Committee
(SAC/TC 209/SC 1).
Drafting organizations of this standard: Textile Industry Standardization
Research Institute, Hutai (Panyu) Textile Printing and Dyeing Co., Ltd.
Textiles - Testing and evaluation for water resistance -
Spray test method
1 Scope
This standard specifies the method for measuring the water resistance of
fabrics by the spray test; gives an evaluation of the water resistance.
This standard applies to fabrics with or without waterproof finishing.
This standard is not applicable to the determination of the water permeability of
fabrics, nor to the prediction of the rain-proof permeability of fabrics.
2 Normative references
The following documents are essential to the application of 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) are applicable to this standard.
GB/T 6529 Textiles - Standard atmospheres for conditioning and testing
(GB/T 6529-2008, ISO 139:2005, MOD)
3 Terms and definitions
The following terms and definitions apply to this document.
3.1
Water resistance
The fabric's resistance to being wetted and penetrated by water. The
indicators of the water resistance of the fabric include the spray rating, the
hydrostatic pressure resistance level, the amount of water penetration.
3.2
Spray rating
The degree to which the surface of the fabric resists being wetted by water.
3.3
5.4 Test water, distilled water or deionized water, the temperature is (20 ± 2) °C
or (27 ± 2) °C. With the consent of relevant parties, test water at other
temperatures can be used; the water temperature is indicated in the test report.
6 Atmosphere for humidity control and test
The standard atmosphere for humidity control and test shall be implemented in
accordance with the requirements of GB/T 6529. With the permission of
relevant parties, humidity control and testing can be carried out at room
temperature or under actual conditions.
7 Specimen
Take at least three specimens from different parts of the fabric. Each specimen
shall be at least 180 mm × 180 mm in size. The specimen shall be
representative and there shall be no wrinkles or creases in the sampling
location.
8 Steps
8.1 Humidify the specimen for at least 4 h under the atmospheric conditions
specified in Chapter 6.
8.2 After the specimen is humidified, use the holder to clamp the specimen
tightly and place it on the support. During the test, the front side of the specimen
faces upwards. Unless otherwise required, the warp or length direction of the
fabric shall be parallel to the direction of water flow.
8.3 Pour 250 mL of test water quickly and steadily into the funnel. Continue to
spray for 25 s ~ 30 s.
8.4 After the spraying stops, immediately remove the holder holding the
specimen, so that the face is almost horizontal. Then gently tap the holder
against a solid hard object. Rotate the holder 180° horizontally. Then tap the
holder lightly again.
8.5 After the tapping, according to the description of the wetness in Table 1,
immediately rank the wetness of the specimen on the holder.
8.6 Repeat 8.1 ~ 8.5 steps to determine the remaining specimens.