Determination of vapor permeability of materials. Protocol for testing samples for vapor permeability. Determination of vapor permeability of sheet materials

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State standard of the USSR GOST 25898-83
"Construction materials and products. Methods for determining the resistance to vapor permeation"
(approved by the Decree of the Gosstroy of the USSR of July 14, 1983 N 180)

building materials and products. Methods of steam-tightness determination

coatings

Non-compliance with the standard is punishable by law

This standard applies to building materials, products and paint coatings and establishes methods for determining the vapor permeability of sheet and film building materials and products, paint coatings, as well as the vapor permeability of materials at a temperature of (20 + - 2) ° С.

The standard does not apply to metal and bulk building materials.

1. General Provisions

1.1. The resistance to vapor permeability of an article is a value numerically equal to the difference in the partial pressure of water vapor in pascals at opposite sides of the article with plane-parallel sides, at which 1 mg of water vapor passes through an area of \u200b\u200bthe product equal to 1 m2 in 1 hour with equal air temperature at opposite sides of the layer.

The vapor permeability of a material is a value numerically equal to the amount of water vapor in milligrams that passes in 1 hour through a layer of material with an area of 1 m2 and a thickness of 1 m, provided that the air temperature at opposite sides of the layer is the same, and the difference in the partial pressure of water vapor is 1 Pa.

1.2. The resistance to vapor permeability is determined for sheet and film building materials, products of which have a thickness of less than 10 mm, as well as paint and varnish vapor barrier coatings. For other materials, vapor permeability is determined.

1.3. The essence of the methods for determining the resistance to vapor permeability and vapor permeability is to create a stationary flow of water vapor through the test sample and determine the magnitude of this flow.

2. Equipment, equipment, materials

2.1. To determine the resistance to vapor permeability and vapor permeability, the following are used:

Laboratory exemplary scales of the 1st category with the highest weighing limit of 200 g according to GOST 24104-80;

See GOST 24104-2001 "Laboratory balance. General technical requirements", put into effect on July 1, 2001 by the Decree of the State Standard of the Russian Federation of October 26, 2001 N 439-st

weekly thermograph M-16 according to GOST 6416-75;

weekly hygrograph M-21 AN;

thermometer TL-19 according to GOST 112-78;

aspiration psychrometer according to GOST 6353-52;

ruler with millimeter divisions according to GOST 427-75;

caliper according to GOST 166-80;

Instead of GOST 166-80, by the Decree of the USSR State Standard of October 30, 1989 N 3253, from January 1, 1991, GOST 166-89 was put into effect

wrist mechanical watch in accordance with GOST 10733-79;

metal cylindrical clips (see. );

"Damn. 1. Metal cylindrical clip"

"Damn. 2. Wardrobe"

glass cups of the CV type with an outer diameter of 100 mm and a height of 30 mm according to GOST 25336-82;

crystallization thick-walled CCT cups with a diameter of 400 mm;

window glass according to GOST 111-78;

Instead of GOST 111-78, the Decree of the Gosstroy of the Russian Federation of May 7, 2002 N 22 approved and entered into force on January 1, 2003 GOST 111-2001

petroleum hard paraffin according to GOST 23683-79;

pine rosin according to GOST 19113-73;

plasticine according to OST 6-15-394-81;

distilled water according to GOST 6709-72;

magnesium nitrate hexahydrate according to GOST 6203-77;

sealing building non-hardening mastic according to GOST 14791-79.

3. Determination of the resistance to vapor permeability of layers of materials

3.1. Sample making

3.1.1. The resistance to vapor permeability of layers of materials is determined on 3 cylindrical specimens with a diameter of 100 mm, cut from the middle part of the product to be tested. It is allowed to determine on samples having the shape of a square with a side of 100 mm in cross section. The surfaces of the samples are cleaned of dust. The planes of the sample must be perpendicular to the direction of moisture flow in the operating conditions of the product. Cracks on samples are not allowed.

3.1.2. For materials, products from which have a thickness of 10-30 mm, the thickness of the sample is equal to the thickness of the product;

For materials whose products have a thickness of more than 30 mm, the thickness of the sample is 30 mm;

for materials with a filler whose dimensions exceed 25 mm and materials with through pores, the thickness of the sample is 60 mm.

3.2. Preparation of samples for testing

3.2.1. Measure the diameter of each sample with a caliper three times. After each measurement, the sample is rotated 60° about its axis of symmetry. The sample diameter is the arithmetic mean of the results of three measurements.

Measure the thickness of the sample three times. After each measurement, the sample is rotated 60° about its axis of symmetry. The thickness of the sample is considered the arithmetic mean of the results of three measurements.

3.2.2. Determine the density of the test material according to the method described in the standard for the method for determining this indicator for this material.

3.2.3. The side surfaces of each sample are covered with a layer of heated mixture of paraffin and rosin (3:1 ratio by weight). The thickness of the applied layer is 2 mm.

3.2.4. The sample is placed on a metal holder. The gaps between the side surface of the sample and the upper face of the metal holder are filled with a heated mixture of paraffin and rosin.

P_1 - P_2 delta_v

R = ───────── - ───────────────,

P_1 - partial pressure of saturated water vapor at

test temperature, determined according to the table, Pa;

delta in - the thickness of the air layer, equal to the distance from the water level

in a glass cup CV to the lower edge of the sample in the holder

at the last weighing, m;

mu_v - vapor permeability of air in a metal cage with

sample equal to 1.01 mg/m x h x Pa;

P_2 - partial pressure of water vapor above the sample, Pa.

The value of P_2 is calculated by the formula

P_2 = ─────────,

phi - average value of relative air humidity in the cabinet

with samples for the last 7 days of testing, determined

according to the readings of the hygrograph and aspiration psychrometer, %.

Saturated vapor pressure versus temperature

Download the file to continue reading...

1. Based on the weighing results, calculate the water vapor flux density through the sample q using the formula:

Mg/(m 2 h) (3.11)

where is the decrease in the mass of a cup with water over time, mg;

– time between two successive weighings, h;

F is the sample area, m2.

2. The resistance to vapor permeability of a layer of material is determined by the formula:

, (m 2 h Pa)/mg (3.12)

where is the partial pressure of saturated water vapor at the test temperature, determined from the table given in Appendix I;

is the thickness of the air layer, equal to the distance from the water level in the cup to the lower edge of the sample in the holder at the last weighing, m;

– vapor permeability of air in a metal case with a sample, equal to 1.01 mg/(m h Pa);

Partial pressure of water vapor above the sample, Pa.

Rice. 3.1. Scheme of the device for determining vapor permeability:

1 - perforated metal shelf; 2 - glass plate; 3 - plasticine; 4 - distilled water; 5 - glass cup type CW; 6 - metal cylindrical clip; 7 - a mixture of paraffin with rosin; 8 - sample of the tested material; 9 - cabinet.

Calculate the value using the formula:

where is the average value of the relative air humidity in the cabinet with samples for the last 7 days of testing, determined by the readings of the CENTER 313 instrument, %.

3. Calculate the coefficient of vapor permeability of the material of each sample using the formula:

Mg/(m h Pa). (3.14)

The coefficients of vapor permeability of building materials obtained experimentally can be further used to assess the vapor permeability of wall enclosing structures made of small-piece building products (brick, wall blocks, etc.)

The paper proposes a calculation method for determining the coefficient of vapor permeability of heterogeneous building enclosing structures.

According to this method, the vapor permeability coefficient is found as a result of solving the inverse problem of water vapor diffusion through the building envelope.

The differential equation for the diffusion of water vapor under stationary conditions according to has the following form

, (3.15)

where is the vapor permeability coefficient of the material, mg/(m h Pa);

– specific vapor capacity of the material, mg/(kg Pa);

- the average density of the material, kg / m 3;

– elasticity of water vapor, Pa;

As an example, consider the determination of the equivalent coefficient of thermal conductivity of masonry from hollow claydite-concrete stones on a cement-sand mortar.

On fig. 3.2 shows a section on expanded clay concrete stone.

Fig. 3.2 Section of expanded clay concrete stone

At the beginning, the value of the coefficient of vapor permeability of expanded clay concrete is determined according to the above method. To do this, three samples with a diameter of 100 mm are cut out of hollow expanded clay concrete stone and vapor permeability tests are carried out.

Based on the test results, the average value of the vapor permeability coefficient is found, which is taken as the calculated one.

To determine the equivalent vapor permeability coefficient of hollow claydite-concrete stone, we use the THERM 6.2 software package, which allows you to find the field of water vapor elasticity.

As initial data, the geometric dimensions of the stone, the values of the coefficients of vapor permeability of expanded clay concrete and air, as well as the coefficients of moisture transfer from the side of internal and external air, are entered.

According to the test results of claydite concrete samples, their vapor permeability coefficient was 0.103 mg/(m·h·Pa), air vapor permeability coefficient according to reference data was 1.01 mg/(m·h·Pa).

The vapor permeability of the entire fence is determined by the formula

, (3.16)

where, - resistance to moisture exchange between air and, respectively, the inner and outer surfaces of the fence, (m 2 h Pa) / mg.

– resistance to vapor permeability of the fencing layer:

– thickness of the i-th layer, m;

– vapor permeability coefficient of the i-th layer, mg/(m·h·Pa).

According to moisture exchange resistance and have the following values:

0.027 (m 2 h Pa)/mg;

0.013 (m 2 h Pa)/mg.

We determine the boundary conditions in the form of moisture transfer coefficients from the side of internal and external air:

\u003d 37.04 mg / (m 2 h Pa);

\u003d 76.92 mg / (m 2 h Pa).

The resistance to vapor permeability of the outer wall according to the calculated field of elasticity of water vapor is found by the formula

Where e in, e n - elasticity of water vapor of internal and external air, Pa;

q P - the intensity of the flow of water vapor through the outer wall, mg / (m 2 h).

Value e in is determined by the formula

Where φ in– relative humidity of internal air, %;

E in– elasticity of full saturation of internal air, Pa.

When performing the calculation, we take the temperature of the internal air \u003d 20 ºС.

The outside air temperature is assumed to be equal to the average temperature of the coldest month = -13.5 ºС for the city of Samara.

The field of elasticity of water vapor in a hollow claydite-concrete stone is shown in fig. 3.3.

Fig.3.3. The field of elasticity of water vapor in a hollow claydite-concrete stone

We determine the value of the water vapor flux density by the formula

\u003d 37.04 (1285.35-1262) \u003d 864.9 mg / (m 2 h)

We find the resistance to vapor permeability from expression (3.17):

(m 2 h Pa)/mg.

The equivalent vapor permeability coefficient of expanded clay concrete stone is determined by the formula

0.1 mg/(m h Pa).

According to the method described above, the coefficient of vapor permeability of a fragment of the masonry of the outer wall, made of hollow claydite-concrete stones on a cement-sand mortar, was determined.

The design of a fragment of the outer wall is shown in fig. 3.4, the field of elasticity of water vapor - in fig. 3.5.

Rice. 3.4. The structure of the wall fragment: 1 – claydite-concrete stones; 2 - cement-sand mortar

Rice. 3.5. Elasticity field of water vapor in masonry of hollow claydite-concrete stones

According to the results of the calculation, the value of the coefficient of vapor permeability of the masonry of expanded clay concrete stones was μ=0.15 mg/(m·h·Pa).

INTERSTATE COUNCIL FOR STANDARDIZATION. METROLOGY AND CERTIFICATION

INTERSTATE

STANDARD

BUILDING MATERIALS AND PRODUCTS

Methods for determining vapor permeability and vapor permeability resistance

(ISO 12572:2001, NEQ)

Official edition

Standard inform 2014

Foreword

The goals, basic principles and basic procedure for work on interstate standardization are established by GOST 1.0-92 “Interstate standardization system. Basic Provisions” and GOST 1.2-2009 “Interstate Standardization System. Interstate standards, rules and recommendations for interstate standardization. Rules for the development, adoption, application. updates and cancellations

About the standard

1 DEVELOPED by the Federal State Budgetary Institution "Research Institute of Building Physics of the Russian Academy of Architecture and Building Sciences" ("NIISF RAASN")

2 INTRODUCED by the Technical Committee TC 465 "Construction"

3 ADOPTED by the Interstate Scientific and Technical Commission for Standardization, Technical Regulation and Conformity Assessment in Construction (MNTKS) (Appendix E to the protocol of December 18, 2012 N9 41)

Short name of the country according to MK (ISO 3100) 004-97	Country code according to MK (ISO 3106) 004-97	Abbreviated name of the national body of state management of construction
		Ministry of Urban Development
Kyrgyzstan		Gosstroy
		Ministry of Construction and Regional Development
		Ministry of Regional Development
Tajikistan		Agency for Construction and Architecture under the Government
Uzbekistan		Gosarchigectstroy

4 8 this standard takes into account the requirements of the international standard ISO 12572:2001 Hydrothermal performance of building materials and products - Determination of water vapor transmission properties (Heat and moisture properties of building materials and products. Determination of vapor permeability characteristics) in terms of test conditions.

Translation from English (en).

Degree of conformity - non-equivalent (NEQ)

5 By order of the Federal Agency for Technical Regulation and Metrology dated December 27, 2012 No. 2013-st, the interstate standard GOST 25898-2012 was put into effect as the national standard of the Russian Federation from January 1, 2014.

6 INSTEAD OF GOST 25898-83

Information about changes to this standard is published in the annual information index "National Standards". and the text of amendments to the amendments - in the monthly information index "National Standards". In case of revision (replacement) or cancellation of this standard, a corresponding notice will be published in the monthly information index "National Standards". Relevant information, notification and texts are also posted in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet

In the Russian Federation, this standard cannot be fully or partially reproduced. replicated and distributed as an official publication without the permission of the Federal Agency for Technical Regulation and Metrology

Appendix A (informative) Determination of the comparative coefficient of vapor permeability ... 6

Appendix E (informative) Values of partial pressure of saturated water vapor .... 10

INTERSTATE STANDARD

BUILDING MATERIALS AND PRODUCTS Methods for determining vapor permeability and resistance to vapor permeability

building materials and products. Methods for determination of water vapor permeability and steam-tightness

Introduction date - 2014-01-01

1 area of use

This International Standard applies to building materials and products, including thin-layer coatings, sheets and films, and specifies methods for determining the vapor permeability of building materials and products and the vapor permeability of thin-layer coatings, sheet and film materials.

The test results are used in heat engineering calculations, for production quality control of building materials and products, and in the development of regulatory documents for materials and products of specific types.

2 Terms and definitions

In this standard, the following terms are used with their respective definitions:

2.1 water vapor flux density

Note - The working surface of the sample is the surface through which the flow of water passes.

2.2 homogeneous material: A material whose density is the same throughout its volume.

2.3 vapor permeability: A value numerically equal to the amount of water vapor in milligrams. passing for 1 hour through a layer of material with an area of 1 m 2 and a thickness of 1 m, provided that the air temperature at opposite sides of the layer is the same, and the difference in partial pressures of water vapor is 1 Pa.

2.4 air permeation resistance at which 1 mg of water vapor passes through a product with an area of 1 m 2 in 1 hour with equal air temperature at opposite sides of the product; a value numerically equal to the ratio of the thickness of the layer of the material under test to the vapor permeability value.

2.5 vapor permeability coefficient of a material measured at a steady steady flow of water vapor through this sample.

2.6 : The ratio of the value of the vapor permeability coefficient of air to the value of the vapor permeability coefficient of the material under test.

Note - The comparative coefficient of vapor permeability shows how much, at the same temperature, the vapor permeability of a layer of material is greater than the vapor permeability of a layer of still air of the same thickness, determined as shown in Appendix A.

2.7 thickness of the layer of still air with resistance to vapor permeation. equivalent to the vapor permeability of the sample: The thickness of the layer of still air with vapor permeability. equal to the vapor permeability of the sample of thickness d.

Official edition

3 General

3.1 The essence of the methods for determining the resistance to vapor permeability and vapor permeability is to create a stationary flow of water vapor through the test sample and determine the intensity of this flow.

This part of ISO 10002 gives the wet-cup and dry-cup methods. The wet cup method is the main one. The "dry cup" method is optional in determining the characteristics of materials and products used in dry operation.

3.2 If the products are used in special conditions, then during testing, the values of temperature and relative humidity of the air can be agreed between the manufacturer and the consumer.

At the request of the consumer, the determination of the vapor permeability of materials and products or the resistance to vapor permeability of thin-layer coatings, films, etc. can be carried out using the “dry cup” method, while a desiccant must be in the vessel under the sample.

3.3 Resistance to vapor permeability is determined for sheet and film building materials with a thickness of less than 10 mm. as well as for thin-layer coatings (thin plaster layers of external insulation systems; roofing roll materials; paintwork, vapor barrier coatings, etc.). For other materials, vapor permeability is determined.

3.4 When testing, to seal the contact areas of the samples to the upper edges of the test vessels, vapor-tight sealants are used that do not change their physical and chemical properties during testing and do not cause changes in the physical and chemical properties of the material of the test sample.

3.5 Symbols and units of measurement

Designations and units of measurement of the main parameters for determining the characteristics of vapor permeability. used in this standard are given in table 1.

Table 1 - Symbols and units of measurement

Parameter name	Designation	Unit
Resistance to vapor permeation of samples		(m 2 h-Pa)/mg
Mass of test vessel with sample
Change in the mass of the test vessel with the sample over time Dt
Time interval between two successive weighings
Air temperature
Relative humidity
Surface area of the sample through which the flow of the water pen passes (the area of the working surface of the sample)
Saturated water vapor pressure
Water vapor pressure
The intensity of the flow of water vapor passing through the sample in 1 h
Air vapor resistance		(m 2 h-La)/mg
Vapor permeability coefficient of the material		mg/(m h - Pa)
Average thickness of the test piece
Water vapor flux density through the sample
Note - 8 in Appendix B is a table for converting units of measurement when determining vapor permeability characteristics.

3.6 The methods given in this standard provide the determination of vapor permeability characteristics with a relative error not exceeding 10%.

4 Test equipment

Test equipment for determining vapor permeability characteristics includes

Test glass vessels (cups):

Means for measuring the thickness of the sample with an accuracy of 0.1 mm or ±0.5%;

Analytical balance with a weighing error of 0.001 g for determining the mass of the test vessel* containing the sample.

When the mass of the vessel with the sample is doubled or more, a balance with a weighing error of 0.01 g is used. The relative error during periodic weighing should not exceed 10%;

A test chamber that maintains the relative humidity of the air<р s so % с точностью±3 % и температуры f=23 "С с точностью ± 0,5 *С.с системой обеспечения циркуля* ции воздуха соскоростьюот 0,02 доО,3м/с. исключающей прямое попадание потока воздуха на образец;

Measuring sensors and instruments for recording temperature and relative air humidity. Measuring sensors and devices are verified in the prescribed manner.

5 Test pieces

5.1 Preparation of samples

5.1.1 Samples shall be representative of the products from which these samples are cut.

5.1.2 Films formed during the manufacture of the product, or coatings glued to products, are removed from the samples when determining the vapor permeability.

5.1.3 During the manufacture of samples, surface damage that may cause a change in the amount or direction of water vapor flow is not allowed.

5.1.4 The area of the working surface of the samples shall be at least 90% of the area of the open surface of the test vessel.

5.2 Dimensions and shape of specimens

5.2.1 For testing, prepare samples of square section with a side of 100 mm or cylindrical section with a diameter of 100 mm.

5.2.2 When testing inhomogeneous materials, it is allowed to produce samples with a diameter (for round samples) or side lengths (for square samples). at least three times the thickness.

5.2.3 Deviation from flatness of the upper and lower surfaces of the samples is allowed no more than 10% of the average value of the sample thickness.

5.3 Thickness of specimens

5.3.1 For materials whose products have a thickness of 10-30 mm. the thickness of the samples must correspond to the thickness of the product. From materials, products from which have a thickness of more than 30 mm. samples are made with a thickness of 30 mm. The thickness of samples from heterogeneous materials (concrete, etc.) should exceed the maximum grain size by 3-5 times.

5.3.2 The thickness of the samples is measured three times by rotating the sample around the axis of symmetry by 60 *. The thickness of the sample is considered the arithmetic mean of the results of three measurements. For specimens of compressible, friable and irregularly shaped specimens, the thickness measurement method used shall be specified in the test report.

5.4 Number of samples

If the area of the working surface of the sample is less than 0.02 m 2 . at least five samples are tested. Otherwise, at least three specimens are tested.

5.5 Sample conditioning

Before testing, the samples are kept at a temperature of (23 ± 5) * C and relative humidity * of air (50 ± 5)% until a constant mass is reached, when the weighing results over the next three days differ by no more than 5%.

6 Testing

6.1 The prepared specimens are placed on top of the test vessel. The gaps between the side faces of the sample and the walls of the vessel are carefully sealed and the first (control) weighing of the vessel with the sample is carried out. If necessary, holding templates are used to fix thin-layer samples. Diagrams of test vessels with samples are presented in Annex B.

6.2 The specimens are set up and tested as follows. so that the direction of the water vapor flow matches the intended water vapor flow during product operation. If the direction of water vapor flow is not known, two identical specimens are made and measurements are made with different directions of water vapor flow.

6.3 In the wet cup test, the sample is placed in a test vessel filled with distilled water. The distance between the surface of the water and the bottom surface of the specimen shall be (15 ± 5) mm. The test vessel containing the sample is then placed in a test chamber maintained at the temperature and relative humidity specified in Clause 4.

With a difference in partial pressures of water vapor in the test vessel and the test chamber, a stream of water vapor arises around the vessel, which passes through the test sample. To determine the water vapor flux density under stationary conditions, the sample vessel is periodically weighed.

In the dry cup test, calcium chloride CaCi 2 is used as the desiccant. magnesium perchlorate Md(Su 4) 2 and analogues.

6.4 When testing according to the “wet cup” method, the test vessels with samples are weighed on an analytical balance at certain intervals, but at least every 7 days. At the time of weighing, the temperature and relative humidity of the air are recorded. The measurement results are recorded in the test report. The form of the test report is given in Appendix D.

6.5 When testing according to the “dry cup” method, the first after the control (see 6.1) weighing of the test vessel with the sample is carried out after 1 hour, the next - after 2.4.12 and then every 24 hours (daily).

6.6 Tests are considered completed after the establishment of a stationary flow of water vapor through the sample, when the flux density during several successive weighings fluctuates by no more than 5% of the average value.

6.7 Tests according to the “dry cup” method are terminated ahead of time if, during the test, the mass of the vessel as a whole increased by more than 1.5 gn for every 25 ml of desiccant in the cup.

6.8 The resistance to vapor penetration of paint and varnish coatings is determined on six samples, three of which are the base and three are the base with the applied layer of paint and varnish coating. As a basis, samples are prepared from the material on which a paint and varnish coating is applied in a real product.

The test report (see Appendix D) contains information about the method of applying the paintwork, the number of layers and other data necessary to identify the coating. Simultaneously with testing the paint coating applied to the substrate, the vapor permeability characteristics of the substrate are determined. The vapor permeation resistance of a paint coating applied to a substrate is defined as the difference between the air permeation resistance of the coated substrate and the air permeation resistance of the substrate.

6.9 Air penetration resistance of the protective, adhesive and decorative layers of external thermal insulation systems with a layer thickness of less than 5 mm can be determined according to 6.8. 8, mineral wool boards are used as the basis, corresponding to the design documentation for the external thermal insulation system. The dimensions of the specimens shall be as given in 5.2.2.

7 Processing of test results

7.1 To calculate the resistance to steam penetration, use the obtained values of the water vapor flux density through the sample, the values of water vapor elasticity in the air of the chamber and in the test vessel under the sample. The values of the partial pressure of saturated water vapor are given in Appendix E.

The test results are recorded in the test report (see Appendix D).

7.2 Based on the results of weighing the test vessel with the sample, calculate the water vapor flux density through the sample q, mg/(h m 2). according to the formula

q = qt/db4, (1)

where dt is the change in the mass of the test vessel with the sample over the time interval DT, mg:

Dt is the time interval between two successive weighings, h;

A is the area of the working surface of the sample through which the flow of water vapor passes. m 2.

7.3 Resistance to vapor permeability of samples R n, (m 2 - h Paumg. Calculate by the formula

where E is the pressure of saturated water vapor in the test vessel. Pa: determined according to Appendix D;

e is the water vapor pressure in the chamber around the vessel. Pa:

/? p in - resistance to vapor permeability of air, (m 2 h Paumg. determined by the formula

where d e is the thickness of the air layer (distance from the water surface in the test vessel to the lower surface of the sample), m;

cv - air permeability in the test vessel. mg / (m h Pa), determined according to Appendix A.

The water vapor pressure in the chamber around the test vessel is determined by the formula

Where<р - относительная влажность воздуха в камере вокруг испытательного сосуда с образцом. %.

7.4 The coefficient of vapor permeability of the material c, mg / (m - h Pa), is determined by the formula

where d is the average thickness of the test specimen, m.

7.5 When calculating the vapor permeability of a material using the “dry cup” method, the value of the difference in partial pressures over the sample is determined from the measured values of temperature I and relative humidity<рв камере (см. раздел 4), а под образцом - при той же температуре и относительной влажности воздуха q^. равной не более 3 %.

Determination of the comparative coefficient of vapor permeability

When determining the comparative coefficient of leopermeability, the designations and units of measurement of the parameters given in Table A.1 are used.

Table A.1 — Symbols and units of measurement of parameters

Parameter name	Designation	Unit
Gas constant for water vapor, equal to 462
Average air pressure
normal atmospheric pressure
Air temperature in the test chamber
Vapor permeability of words of still air		mg/(mh-Pa)
Comparative vapor permeability coefficient
The thickness of a layer of still air that has resistance to vapor permeation. equivalent to the vapor permeability of the test specimen of thickness d

The comparative coefficient of air permeability is calculated as the ratio of the air permeability of a layer of still air to the vapor permeability of the material under test, q # / c.

To calculate the vapor permeability of a layer of still air, Schirmer's formula is used. which uses the average air pressure p during the test

I, “[O-Ov3ru/?^, T rCG/2731" "1 1A.1>

or determined graphically according to the graph of the dependence of the coefficient of vapor permeability of air on pressure at a temperature of 23 "C (see Figure A.1).

The air pressure during the test p is determined by a barometer.

Kffifmit gschyadronitsmmmootm tub y ^ riCT 10, shfeoPa)

Figure A.1 - Graph of the dependence of the coefficient of vapor permeability of air on pressure

at a temperature of 23 * C

The thickness of the layer of still air S & vapor resistance. equivalent to the vapor permeability of the tested sample of material of thickness d. determined by the formula

Vapor permeability conversion table

Table B.1

Name sing ten "	measurements	Other unit of measure	Transferable coefficient
Water vapor flux density
Permeation resistance coefficient	kg / (m 2 -s Pa)	mg / (m 2 h - Pa)
Permeation resistance	<м 2 -с-Па)/кг	(m g -h -Pa)/mg
Vapor permeability (larol permeability coefficient)	kg/(m s Pa)	mg7(m h - Pa)
Comparative vapor permeability coefficient
Water vapor flow per unit time

Diagrams of test vessels with samples

Test sample: 2 - retaining template (if necessary): 3 - sealant. 4 - distilled water. 5 - glass test vessel

Figure B.1 — Diagram of a test vessel with a sample (wet cup method)

1 - test sample. 2 - retaining template (if necessary): 3 - sealant: 4 - desiccant (calcium chloride CaClj, magnesium perchlorate MpCCID or amalosh]: 5 - glass test vessel

Figure 8.2 - Diagram of a test vessel with a sample (dry cup method)

1 - test sample of bulk material. 2- lattice or vapor-permeable membrane. 3 - distilled water

Figure B.3-Scheme of a test vessel with a sample of bulk material

Vapor Permeability Test Report Form

Material (name, marking, manufacturer, batch) __________________. material density ________________ “g/m*;

sample thickness<7_____________ м; площадь рабочей поверхности образца А__________ м г:

internal sample dimensions_________________mm; distance from the water surface to the lower surface of the sample _ _ ......mm;

vapor permeability resistance of the air layer from the water surface to the lower surface of the sample R na __________ (m g - h PeUmg

Special conditions for conducting an examination

Weight of vessel with water or with water absorber, t

The amount of water vapor passed through the sample in an interval

aoem «1u, vn mg

Time interval between measurements. Dt.h

The intensity of the lots of water vapor /. mgLt

Sweat density of water container a mg^mH

Mean meteorological dagime for the period between measurements

Resistance larolro-nitsenio Ya „. (m * h Pa (Lig

Vapor permeability l. mg/(m -h Pa)

air in the chamber (. -s

Humidity ■year in

Partial pressure of hot steam

sample E. Pa

in the surrounding air a. Pa

pressure difference E-e. Pa

GOST 25898-2012

Saturated water vapor partial pressure values

The following appendix gives the values of the partial pressure of saturated water vapor E in pascals at an air temperature above water from 17.0 "C to 26.9" C (see Table E.1).

Table E.1 - Partial pressure of saturated water vapor

UDC 669.001.4:006.354 MKS 91.100.01 Zh19 NEQ

Key words: vapor permeability. water vapor flux density, vapor permeation resistance, thin-layer coatings, films, building materials and products

Editor I Z. Fateeva Technical editor V.N. Prusakova Proofreader V.I. Varenioaa Computer layout O.D. Cherepkova

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STATE STANDARD OF THE UNION OF THE SSR

MATERIALS AND PRODUCTS
BUILDING

METHODS FOR DETERMINING RESISTANCE TO VAPOR PERMEABILITY

GOST 25898-83

USSR STATE COMMITTEE
CONSTRUCTION

Moscow

DEVELOPED by the Research Institute of Building Physics (NIISF) of the USSR State Construction Committee

Research Institute of Construction and Architecture of the Gosstroy of the Lithuanian SSR

PERFORMERS

F.V. Ushkov, Dr. tech. sciences; V.R. Khlevchuk, cand. tech. sciences; AND I. Kiselev, cand. tech. sciences; IN AND. Stankevičius, cand. tech. sciences; E.E. Monstvilas; I.S. Lifanov

INTRODUCED by the Research Institute of Building Physics (NIISF) of the USSR State Construction Committee

Deputy directors F.V. Ushkov

APPROVED AND INTRODUCED BY Resolution No. 180 of the USSR State Committee for Construction Affairs dated July 14, 1983

STATE STANDARD OF THE UNION OF THE SSR

By the Decree of the State Committee of the USSR for Construction Affairs dated July 14, 1983 No. 180, the deadline for the introduction was established

from 01.01.84

This standard applies to building materials, products and paint coatings and establishes methods for determining the vapor permeability of sheet and film building materials and products, paint and varnish coatings, as well as the vapor permeability of materials at a temperature of (20 ± 2) ° WITH.

The standard does not apply to metal and bulk building materials.

1. General Provisions

1.1. Resistance to vapor permeability of the product - a value numerically equal to the difference in the partial pressure of water vapor in pascals at opposite sides of the product with plane-parallel sides, at which 1 mg of water vapor passes through an area of \u200b\u200bthe product equal to 1 m 2 in 1 hour with equal air temperature at opposite sides of the layer .

The vapor permeability of the material is a value numerically equal to the amount of water vapor in milligrams that passes in 1 hour through a layer of material with an area of 1 m 2 and a thickness of 1 m, provided that the air temperature at opposite sides of the layer is the same, and the difference in the partial pressure of water vapor is 1 Pa .

2. Equipment, equipment, materials

2.1. To determine the resistance to vapor permeability and vapor permeability, the following are used:

laboratory exemplary scales of the 1a category with the highest weighing limit of 200 g according to GOST 24104-80;

weekly thermograph M-16 according to GOST 6416-75;

weekly hygrograph M-21 AN;

thermometer TL-19 according to GOST 112-78;

aspiration psychrometer according to GOST 6353-52;

ruler with millimeter divisions according to GOST 427-75;

caliper according to GOST 166-80;

wrist mechanical watch in accordance with GOST 10733-79;

metal cylindrical clips (see drawing 1);

closet (see fig. 2);

glass cups of the CV type with an outer diameter of 100 mm and a height of 30 mm according to GOST 25336-82;

crystallization thick-walled CCT cups with a diameter of 400 mm;

window glass according to GOST 111-78;

petroleum hard paraffin according to GOST 23683-79;

pine rosin according to GOST 19113-84;

plasticine according to OST 6-15-394-81;

distilled water according to GOST 6709-72;

magnesium nitrate hexahydrate according to GOST 6203-77;

sealing building non-hardening mastic according to GOST 14791-79.

Metal cylindrical clip

1 - a wall made of vapor-tight material; 2 - doors made of vapor-proof material; 3 - perforated shelf

3.1.2. For materials whose products have a thickness of 10 - 30 mm, the thickness of the sample is equal to the thickness of the product;

for materials whose products have a thickness of more than 30 mm, the thickness of the sample is 30 mm;

for materials with a filler whose dimensions exceed 25 mm and materials with through pores, the thickness of the sample is 60 mm.

3.2.

3.2.4. The sample is placed on a metal holder. The gaps between the side surface of the sample and the upper face of the metal holder are filled with a heated mixture of paraffin and rosin.

1 - glass plate; 2 - plasticine; 3 - distilled water; 4 - glass cup type CV; 5 - metal cylindrical clip; 6 - a mixture of paraffin with rosin; 7

3.3. Conducting a test

3.3.5. Every 7 days after the start of the test, a glass cup of CV with distilled water is removed from the metal holder and weighed. When weighing, the cup is covered with a circle of thin tin with a diameter of 110 mm.

After weighing, the sample is prepared to continue the test in accordance with paragraph 3.2.6 and continue testing in accordance with paragraphs. 3.3.1 - 3.3.4 .

3.4.

1 - cabinet shelf; 2 - glass cup CV; 3 - distilled water; 4 - plasticine; 5 - a mixture of paraffin with rosin; 6 - a sample of the tested material

4.3. Conducting a test

4.4.3. Application of the method makes it possible to determine the resistance to vapor permeability of sheet material with a relative error not exceeding 10%.

5. Determination of resistance to vapor permeability of layers of paint and varnish coatings

5.1. Sample making

5.1.1. Determination of the resistance to vapor permeability of the paintwork is carried out on 6 samples. The first three of them are samples of the material on which the paint is applied in a real product. The second three are samples of this material with a paint coating applied in accordance with technological standards. Sample diameter 100 mm. It is allowed to determine the resistance to vapor permeability on samples having a square section with a side of 100 mm. The thickness of the samples of the first three should be equal to the thickness of the product to be coated, but should not exceed 10 mm.

5.2. Preparation of samples for testing

5.2.1. The preparation of samples for testing is carried out in accordance with paragraphs. 4.2.1 and 4.2.2. The coated samples are mounted onto the cup with the CV coated down.

5.3. Conducting a test

5.3.1. Sample testing is carried out in accordance with paragraphs. 4.3.1 - 4.3.4 .

5.4. Processing test results

5.4.1. Resistance to vapor permeation of a material sample without paint coating R1 in m 2 × h ×

The total resistance to vapor permeability of the sample of the material and the layer of paint and varnish applied on it R2 in m 2 × h × Pa/mg is calculated in accordance with paragraphs. 4.4.1 and 4.4.2.

Vapor permeability of the paint layer R1 in m 2 × h × Pa / mg is determined by the formula

R1 = R2 - R1.

5.4.2. The application of the method makes it possible to determine the resistance to vapor permeability of a layer of paintwork with a relative error not exceeding 10%.

Annex A (informative). Determination of the comparative coefficient of vapor permeability Appendix B (reference). Vapor Permeability Unit Conversion Table Appendix B (recommended). Schemes of test vessels with samples Appendix D (recommended). The form of the test report for vapor permeability Appendix E (informative). Saturated water vapor partial pressure values

Interstate standard GOST 25898-2012
"Construction materials and products. Methods for determining vapor permeability and vapor permeability resistance"
(put into effect by order of the Federal Agency for Technical Regulation and Metrology dated December 27, 2012 N 2013-st)

building materials and products. Methods for determination of water vapor permeability and steam-tightness

Foreword

Goals, basic principles and the basic procedure for work on interstate standardization are established by GOST 1.0-92 "Interstate standardization system. Basic provisions" and GOST 1.2-2009 "Interstate standardization system. Interstate standards, rules and recommendations for interstate standardization. Rules for the development, adoption, application , updates and cancellations"

1 area of use

2 Terms and definitions

In this standard, the following terms are used with their respective definitions:

2.1 water vapor flux density: The mass of the flow of water vapor passing through the unit area of the working surface of the sample per unit time.

Note - The working surface of the sample is the surface through which the flow of water vapor passes.

2.2 homogeneous material: A material whose density is the same throughout its volume.

2.3 vapor permeability: A value numerically equal to the amount of water vapor in milligrams passing in 1 hour through a layer of material with an area of 1 and a thickness of 1 m, provided that the air temperature on opposite sides of the layer is the same, and the difference in partial pressures of water vapor is 1 Pa.

2.4 vapor permeation resistance: An indicator characterizing the difference in partial pressures of water vapor in pascals at opposite sides of a product with plane-parallel sides, at which 1 mg of water vapor passes through a product with an area of 1 in 1 hour with equal air temperature at opposite sides of the product; a value numerically equal to the ratio of the thickness of the layer of the material under test to the vapor permeability value.

2.5 vapor permeability coefficient of the material: Calculated thermotechnical indicator, defined as the ratio of the thickness of a material sample d to the vapor permeability resistance, measured with a steady steady flow of water vapor through this sample.

2.6 comparative coefficient of vapor permeability: The ratio of the value of the coefficient of vapor permeability of air to the value of the coefficient of vapor permeability of the material under test.

Note - The comparative coefficient of vapor permeability shows how much at the same temperature the resistance to vapor permeability of a layer of material is greater than the resistance to vapor permeability of a layer of still air of the same thickness; determined as shown in Annex A.

2.7 thickness of a layer of still air with vapor permeability equivalent to that of the sample: Thickness of a layer of still air with vapor permeability equal to that of a sample of thickness d.

3 General

This part of ISO 10002 gives the wet-cup and dry-cup methods. The wet cup method is the main one. The "dry cup" method is an additional method for determining the characteristics of materials and products used in dry operation.

3.2 If the products are used in special conditions, then during testing, the values of temperature and relative humidity of the air can be agreed between the manufacturer and the consumer.

At the request of the consumer, the determination of the vapor permeability of materials and products or the vapor permeability of thin-layer coatings, films, etc. can be carried out by the "dry cup" method, while a desiccant must be in the vessel under the sample.

3.3 Resistance to vapor permeability is determined for sheet and film building materials with a thickness of less than 10 mm, as well as for thin-layer coatings (thin plaster layers of external insulation systems; roofing roll materials; paintwork, vapor barrier coatings, etc.). For other materials, vapor permeability is determined.

3.4 When testing, to seal the areas of contact of samples to the upper edges of the test vessels, vapor-tight sealants are used that do not change their physical and chemical properties during testing and do not cause changes in the physical and chemical properties of the material of the test sample.

3.5 Symbols and units of measurement

The designations and units of measurement of the main parameters for determining the vapor permeability characteristics used in this standard are given in table 1.

Table 1 - Symbols and units of measurement

Parameter name	Designation	Unit
Resistance to vapor permeation of samples
Weight of test vessel with sample
Change in the mass of the test vessel with the sample over time
Time interval between two successive weighings
Air temperature
Relative humidity
Sample surface area through which water vapor flows (sample working surface area)
Saturated water vapor pressure
Water vapor pressure
The intensity of the flow of water vapor passing through the sample in 1 h
Air vapor resistance
Vapor permeability coefficient of the material
Average thickness of the test piece
Water vapor flux density through the sample
Note - Appendix B provides a table for the conversion of units of measurement when determining vapor permeability characteristics.

3.6 The methods given in this standard provide the determination of vapor permeability characteristics with a relative error not exceeding 10%.

4 Test equipment

Vapor permeability testing equipment includes:

Test glass vessels (cups);

Means for measuring the thickness of the sample with an accuracy of 0.1 mm or;

Analytical balance with a weighing error of 0.001 g for determining the mass of the test vessel with the sample.

When the mass of the vessel with the sample is doubled or more, a balance with a weighing error of 0.01 g is used. The relative error during periodic weighing should not exceed 10%;

A test chamber that maintains relative air humidity with accuracy and temperature t = 23 ° C with accuracy , with an air circulation system at a speed of 0.02 to 0.3 m/s, excluding direct air flow on the sample;

Measuring sensors and instruments for recording temperature and relative air humidity. Measuring sensors and devices are verified in the prescribed manner.

5 Test pieces

5.1 Preparation of samples

5.1.1 Samples shall be representative of the products from which these samples are cut.

5.1.2 Films formed during the manufacture of the product, or coatings glued to products, are removed from the samples when determining the vapor permeability.

5.1.3 During the manufacture of samples, surface damage that may cause a change in the amount or direction of water vapor flow is not allowed.

5.1.4 The working surface area of the specimens shall be at least 90% of the open surface area of the test vessel.

5.2 Dimensions and shape of specimens

5.2.1 For testing, prepare samples of square section with a side of 100 mm or cylindrical section with a diameter of 100 mm.

5.2.2 When testing inhomogeneous materials, it is allowed to produce samples with a diameter (for round samples) or side lengths (for square samples) that exceed the thickness by at least three times.

5.2.3 Deviation from the flatness of the upper and lower surfaces of the samples is allowed no more than 10% of the average value of the sample thickness.

5.3 Thickness of specimens

5.3.1 For materials whose products have a thickness of 10-30 mm, the thickness of the samples must correspond to the thickness of the product. Samples with a thickness of 30 mm are made from materials whose products have a thickness of more than 30 mm. The thickness of specimens made of inhomogeneous materials (concrete, etc.) should exceed the maximum grain size by 3-5 times.

5.3.2 The thickness of the specimens is measured three times by rotating the specimen about the axis of symmetry by 60°. The thickness of the sample is considered the arithmetic mean of the results of three measurements. For samples of compressible, friable and irregularly shaped samples, the thickness measurement method used is indicated in the test report.

5.4 Number of samples

If the working surface area of the sample is less than 0,02, at least five samples are tested. Otherwise, at least three specimens are tested.

5.5 Sample conditioning

Before testing, the samples are kept at temperature and relative humidity until a constant weight is reached, when the weighing results over the next three days differ by no more than 5%.

6 Testing

6.2 The specimens are placed in the test vessel so that the direction of the water vapor flow corresponds to the expected water vapor flow during the operation of the product. If the direction of water vapor flow is not known, two identical specimens are made and measurements are made with different directions of water vapor flow.

6.3 In the wet cup test, the specimen is placed in a test vessel containing distilled water. The distance between the surface of the water and the bottom surface of the specimen shall be mm. The test vessel containing the specimen is then placed in a test chamber maintained at the temperature and relative humidity specified in Clause 4.

With a difference in partial pressures of water vapor in the test vessel and the test chamber, a stream of water vapor is generated around the vessel, which passes through the test sample. To determine the water vapor flux density under stationary conditions, the vessel with the sample is periodically weighed.

When tested by the "dry cup" method, calcium chloride, magnesium perchlorate and analogues are used as a desiccant.

6.4 When testing according to the "wet cup" method, test vessels with samples are weighed on an analytical balance at certain intervals, but at least every 7 days. At the time of weighing, the temperature and relative humidity of the air are recorded. The measurement results are recorded in the test report. The form of the test report is given in Appendix D.

6.5 When testing according to the "dry cup" method, the first after the control (see 6.1) weighing of the test vessel with the sample is carried out after 1 hour, the next - after 2, 4, 12 and then every 24 hours (daily).

6.7 The dry cup test is terminated prematurely if, during the test, the mass of the sample container increases by more than 1.5 g for every 25 ml of desiccant in the cup.

6.8 The resistance to vapor permeability of paint and varnish coatings is determined on six samples, three of which are the base and three are the base with the applied layer of paint and varnish coating. As a basis, samples are prepared from the material on which a paint and varnish coating is applied in a real product.