GB/T 45365-2025Textiles - Determination of moisturizing effect - Measurement of microclimate using sweating guarded hotplate (English PDF)

Foreword

This document was drafted in accordance with the rules provided in GB/T 1.1-2020 Directives

for Standardization - Part 1.Rules for the Structure and Drafting of Standardizing Documents.

This document modifies and adopts ISO 21232.2018 Textiles - Determination of Moisturizing

Effect of Textile Materials by Measurement of Microclimate between Textiles and Simulated

Human Skin Using Sweating Guarded Hotplate.

In comparison with ISO 21232.2018, this document makes the following structural adjustments.

---6.2.2 corresponds to 6.3.2 of ISO 21232.2018;

---6.2.4 corresponds to 6.2.2 of ISO 21232.2018;

---6.3.2 corresponds to 6.3.3 of ISO 21232.2018;

---6.2.3 and 6.3.3 are added.

The technical differences between this document and ISO 21232.2018 and the causes for these

differences are as follows.

---The requirement that "the size of the frame shall be consistent with the size of the

sweating guarded hotplate" is added (see 5.3), and meanwhile, the annotation of the

frame side length in Figure 3 is deleted (see Figure 3 of ISO 21232.2018) to ensure that

the frame size matches the sweating guarded hotplate;

---The normative reference GB/T 6529 is used to replace ISO 139 (see 6.1.2) to adapt to

the technical conditions of China;

---The normative reference GB/T 11048-2018 is used to replace ISO 11092.2014 (see 5.1,

5.5, 6.2.3, 6.3.1, and A.3 of Appendix A) to adapt to the technical conditions of China;

---The allowable deviations of temperature, relative humidity and wind speed are added

(see 6.2.2) to improve the operability of the test;

---The determination of instrument constants is added (see 6.2.3) to improve the operability

of the test;

---The specimen installation requirements are added (see 6.2.4) to improve the accuracy

of the test;

---The provisions on result calculation and value are added (see 6.3.3) to unify the result

calculation and value requirements;

---The number of determinations of hydration value is modified (see A.3; A.3 in Appendix

A of ISO 21232.2018) to improve the stability of the results.

Textiles - Determination of Moisturizing Effect -

Measurement of Microclimate Using Sweating Guarded

Hotplate

1 Scope

This document describes a test method for determining the moisturizing effect of textile

materials by measuring the water-vapor resistance including air layer and relative humidity by

means of a sweating guarded hotplate under simulated microclimate conditions.

This document is applicable to all types of clothing fabrics. Films, leather and multi-layer

composite materials may take this as a reference.

2 Normative References

The contents of the following documents constitute indispensable clauses of this document

through the normative references in the text. In terms of references with a specified date, only

versions with a specified date are applicable to this document. In terms of references without a

specified date, the latest version (including all the modifications) is applicable to this document.

GB/T 6529 Textiles - Standard Atmospheres for Conditioning and Testing (GB/T 6529-2008,

ISO 139.2005, MOD)

GB/T 11048-2018 Textiles - Physiological Effects - Measurement of Thermal and Water-vapor

Resistance under Steady-state Conditions (sweating guarded-hotplate test) (ISO 11092.2014,

MOD)

3 Terms and Definitions

The following terms and definitions are applicable to this document.

4 Principle

In order to simulate the microclimate, a device is designed to separate the specimen from the

hotplate, which contains a humidity sensor. The hotplate is covered with a breathable and water-

impermeable film to simulate the hydration of the skin. The moisturizing effect of the textiles

is determined by measuring the water-vapor resistance including air layer (Ret_al) and the relative

humidity between the sweating guarded hotplate and the specimen.

NOTE. the wearing comfort of clothing usually depends on the microclimate environmental

conditions (humidity and temperature) between the skin and the fabric. The test method in

this document simulates the moisturizing mechanism of textiles when they act as a barrier

to prevent moisture evaporation, and the ability of textiles to maintain moisture equilibrium

Appendix A

(normative)

Evaluation of Hydration Value

A.1 Measurement Principle

The electrical properties of the skin surface depend on the moisture content of the epidermal

stratum corneum. The dielectric constant of the epidermal stratum corneum is obtained by

measuring the capacitance with a dielectric constant tester or a skin moisture tester. The

difference between the dielectric constant of water (81) and the dielectric constant of the

epidermal stratum corneum is used to evaluate the hydration of the epidermis. After the skin

surface is hydrated, the attenuation change of the capacitance will lead to the change of the

dielectric constant.

A.2 Dielectric Constant Tester

The dielectric constant tester or skin moisture tester has two electrodes (positive and negative).

The electromagnetic field formed by these two electrodes can determine the dielectric

properties of the stratum corneum.

A.3 Measurement of Hydration Value

The surface of the porous plate is kept moist by a water supply device (see Figure 1). In

accordance with the test conditions and procedures specified in 7.4 of GB/T 11048-2018, a

breathable and water-impermeable film shall be covered on the porous plate. After the

temperature of the test plate, air temperature, humidity and heating power reach a stable state,

measure the hydration value.

Place the probe on the film surface to measure for 1 second. Measure at least 10 times in

different areas and take the average value. After each measurement, clean the probe. The

measured capacitance change depends on the moisture content of the sample.

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