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GB/T 17794-2021 English PDF (GBT17794-2021)

GB/T 17794-2021 English PDF (GBT17794-2021)

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GB/T 17794-2021: Preformed flexible elastomeric foam thermal insulation

This document specifies the classification and marking, requirements, test methods, inspection rules, logos, labels, operating instructions, packaging, transportation, and storage of flexible elastomeric foam thermal insulation products. This document is applicable to flexible elastomeric foam products for thermal insulation with a service temperature of -196 ????~175 ????. This document is also applicable to flexible elastomeric foam products with veneer.
GB/T 17794-2021
GB
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 91.120.10
CCS Q 25
Replace GB/T 17794-2008
Preformed flexible elastomeric foam thermal insulation
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ISSUED ON: AUGUST 20, 2021
IMPLEMENTED ON: MARCH 1, 2022
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and Definitions ... 6
4 Classification and marking ... 6
5 Requirements ... 7
6 Test methods ... 9
7 Inspection rules ... 13
8 Logos, labels, and operating instructions ... 14
9 Packaging, transportation, and storage ... 15
Appendix A (Normative) Measuring methods for the dimensions and volumes of pipes ... 16
Appendix B (Normative) Determination method for vacuum volume water absorption ... 18
Preformed flexible elastomeric foam thermal insulation
1 Scope
This document specifies the classification and marking, requirements, test methods, inspection rules, logos, labels, operating instructions, packaging, transportation, and storage of flexible elastomeric foam thermal insulation products.
This document is applicable to flexible elastomeric foam products for thermal insulation with a service temperature of -196 ???~175 ???. This document is also applicable to flexible elastomeric foam products with veneer.
2 Normative references
The following documents contain the provisions which, through normative reference in this document, constitute the essential provisions of this document. For the dated referenced documents, only the versions with the indicated dates are applicable to this document; for the undated referenced documents, only the latest version (including all the amendments) is applicable to this document.
GB/T 2406.2 Plastics - Determination of burning behaviour by oxygen index - Part 2: Ambient-temperature test
GB/T 2918 Plastics - Standard atmospheres for conditioning and testing
GB/T 4132 Definitions of terms relating to thermal insulating materials GB/T 6342 Cellular plastics and rubbers - Determination of linear dimensions GB/T 6343 Cellular plastics and rubbers - Determination of apparent density GB/T 6669-2008 Flexible cellular polymeric materials - Determination of compression set
GB 8624 Classification for burning behavior of building materials and products GB/T 8627 Test method for density of smoke from the burning or decomposition of building materials
GB/T 8811 Test method for dimensional stability of rigid cellular plastics GB/T 10294 Thermal insulation - Determination of steady-state thermal resistance and related properties - Guarded hot plate apparatus
GB/T 10295 Thermal insulation - Determination of steady-state thermal resistance and related properties - Heat flow meter apparatus
GB/T 16422.2 Plastics - Methods of exposure to laboratory light sources - Part 2: Xenon-arc lamps
GB/T 17146 Test methods for water vapour transmission properties of building materials and products
GB/T 17430 Estimating the maximum service temperature of thermal insulation GB/T 25996 Test method for thermal insulations on external stress corrosion cracking of austenitic stainless steel
GB/T 29899 Determination of the emission of volatile organic compounds from wood-based panels and furnishing - Small chamber method
GB/T 34005 Determination of water vapour transmission properties of preformed pipe insulation
JC/T 618 Methods of chemical analysis of thermal insulation materials for leachable chloride, fluoride, silicate, sodium ions
JC/T 2495 Dienes foam products for thermal insulation
3 Terms and Definitions
The terms and definitions defined in GB/T 4132 and the following terms and definitions apply to this document.
3.1 preformed flexible elastomeric foam thermal insulation; FEF
A flexible thermal insulation product with a closed-cell structure, which is based on natural or synthetic rubber and contains other polymers or chemicals, and is modified by organic or inorganic additives and processed by mixing, extrusion, foaming, cooling and shaping.
3.2 apparent density
The mass of a unit volume of foam at a specified temperature and relative humidity. 4 Classification and marking
4.1 Classification
The test environment and the conditioning of the specimen shall be in accordance with the provisions of GB/T 2918. The temperature shall be (23??2) ??C, the relative humidity shall be (50??10) %, and the time of conditioning shall be not less than 24 h. 6.2 Specimen preparation
Specimens shall be prepared in as-supplied state. When a product is not suitable for the test or preparation of a specimen due to its shape, it shall be replaced by a board produced through the same formula, the same process and at the same time, and having the same density (the apparent density deviation shall be ??5 kg/m3).
6.3 Appearance quality
Under natural lighting conditions, carry out the visual inspection within a distance of 1 m.
6.4 Dimensions and allowable deviations
For boards, take a whole board to measure according to the provisions of GB/T 6342; for pipes, take a whole pipe to measure in accordance with the provisions of Appendix A.
6.5 Apparent density
The determination shall be carried out in accordance with the provisions of GB/T 6343. The determination of the volume of the pipe shall be carried out according to the provisions of Appendix A.
6.6 Thermal conductivity
The determination shall be carried out in accordance with the provisions of GB/T 10294 or GB/T 10295, the arbitration shall be carried out according to the provisions of GB/T 10294.
6.7 Vacuum volume water absorption
The determination shall be carried out in accordance with the provisions of Appendix B.
6.8 Moisture permeability coefficient and moisture resistance factor
The determination of the moisture permeability of the board shall be carried out according to the desiccant method in GB/T 17146, and the determination and calculation of the moisture permeability of the pipe shall be carried out according to the provisions of GB/T 34005. The temperature of the test studio (or constant temperature and humidity chamber) shall be (25??0.5) ??C, and the relative humidity shall be (75??3) %. When the product has a veneer, only the moisture resistance factor needs to dimensions of the specimen at a temperature of (23??2) ??C.
6.10.1.5 The test results of the board specimens shall be expressed as the arithmetic mean values of the dimensional change rates in the length, width, and thickness directions of the three specimens, respectively. The test results of the tubular specimens are expressed as the arithmetic mean values of the dimensional change rates in the length and wall thickness directions of the three specimens, respectively. 6.10.2 Low-temperature tensile strength and low-temperature impact resistance The determination of DW-type products shall be carried out in accordance with the provisions of JC/T 2495.
6.10.3 Maximum service temperature
The determination of GW-type products shall be carried out in accordance with the provisions of GB/T 17430. The temperature of the hot plate shall be agreed upon by the supplier and the buyer or offered by the manufacturer, but shall not be lower than 150 ??C. The temperature deviation shall be ??3 ???, and the exposure time shall be 96 h. The dimensions of the specimen shall not be less than (150??2) mm ?? (450??2) mm ?? the original thickness, and if necessary, it can be superimposed in multiple layers to ensure that the cold surface temperature is not higher than 50 ??C. For tubular products, board products produced by the same process and having the same density can be used for the test. Let the hot surface of the specimen face outward, fold the specimen along the length direction at the center of the cold surface to 90?? around a steel pipe with an outer diameter of (22??1) mm, and observe whether there are visible cracks at the bending of the specimen.
6.11 Combustion performance
6.11.1 The determination of the oxygen index shall be carried out in accordance with the provisions of GB/T 2406.2, the determination of the smoke density shall be carried out in accordance with the provisions of GB/T 8627, and the thickness of the specimen for smoke density test shall be no more than 25 mm.
6.11.2 The determination of the products used in the construction field shall be carried out according to the method specified in GB 8624.
6.12 Release of TVOC
The determination shall be carried out according to the provisions of GB/T 29899; use a 1 m3 small release chamber; the temperature shall be (23??0.5) ???, the relative humidity shall be (50??3) %, the product load rate shall be 1, and the air exchange rate shall be 1 time per hour.
6.13 Anti-aging properties
Carry out the determination according to the provisions of GB/T 16422.2. Test conditions: The irradiance shall be 550 W/m2, and the black mark temperature shall be (65??3) ??C; in the test chamber, the temperature shall be (38??3) ??C, the relative humidity shall be (50??5) %, and no rainfall is required. Specimen dimensions: the board product shall be (150??2) mm ?? (75??1) mm ?? the original thickness, and the tubular product shall be length (100??2) mm ?? the original inner diameter ?? the original wall thickness. 6.14 pH value of the leachate
The determination shall be carried out according to the provisions of JC/T 618. 6.15 Stress corrosion
The determination shall be carried out according to the provisions of GB/T 25996. 7 Inspection rules
7.1 Factory inspection and type inspection
7.1.1 Factory inspection
The inspection items of the factory inspection include the dimensions and allowable deviations, appearance quality, apparent density, vacuum volume water absorption, and compression rebound rate.
7.1.2 Type inspection
Type inspection shall be carried out in one of the following situations: a) The type approval of a new product;
b) After the formal production, there are major changes in the raw materials or processes, which may affect the performance of the product;
c) During normal production, at least once a year;
d) When there is a big difference between the factory inspection results and the results of the last type inspection;
e) When the production is resumed after being stopped for more than 6 months. The inspection items for type inspection are those specified in 5.1~5.4. According to the requirements of the application environment, the supplier and the buyer can negotiate whether the items in 5.5 are necessary for the inspection.
7.2 Batching and sampling
Appendix A
(Normative)
Measuring methods for the dimensions and volumes of pipes
A.1 Measuring tools
A.1.1 Steel tape: The graduation value shall be 1 mm.
A.1.2 Precision diameter tape: The division value shall be not less than 0.2 mm. A.1.3 Caliper: The graduation value shall be not less than 0.05 mm.
A.2 Measurement procedure
A.2.1 Length
Use a steel tape to measure the two opposite ends of the outer side of the pipe; take the arithmetic mean of the two measurement results as the length l, and the value shall be rounded to an integer.
A.2.2 Outer diameter
Use a precision diameter tape to measure at both ends and the middle of the pipe; take the average value of the three measurement results as the outer diameter d1 of the pipe, and the value shall be rounded to 0.2 mm.
A.2.3 Wall thickness
Use a caliper to measure at both ends of the pipe, take the average value of the two measurement results as the wall thickness h, and the value shall be rounded to 0.2 mm. A.2.4 Inner diameter
Calculate the inner diameter d of the pipe according to formula (A.1), and round the calculation result off to one decimal place.
Where:
d --- The inner diameter of the pipe, in millimeters (mm);
d1 --- The outer diameter of the pipe, in millimeters (mm);
Appendix B
(Normative)
Determination method for vacuum volume water absorption
B.1 Principle
When a flexible elastomeric foam is immersed in water, due to its closed-cell structure, the water is not easy to fill the pores. However, under a certain degree of vacuum, water can quickly enter the pores, so as to quickly and accurately measure the water absorption performance of the product, and reflect whether the closed-cell structure is complete.
B.2 Instruments and equipment
B.2.1 Balance: The division value shall be not less than 0.001 g.
B.2.2 Vacuum container.
B.2.3 Vacuum pump: The vacuum degree shall be not lower than (85??3) kPa. B.2.4 Distilled water.
B.2.5 Stopwatch.
B.2.6 Steel ruler: The graduation value shall be 1 mm.
B.2.7 Precision diameter tape: The division value shall be not less than 0.2 mm. B.2.8 Caliper: The graduation value shall be not less than 0.05 mm.
B.2.9 Specimen holder.
B.3 Specimens
B.3.1 Cut 3 specimens from the samples. The dimensions of the board specimen shall be (100??1) mm ?? (100??1) mm ?? the original thickness; the dimensions of the tubular specimen shall be (100??1) mm ?? the original inner diameter ?? the original wall thickness.
B.3.2 In a standard environment with a temperature of (23??2) ??C and relative humidity of (50??10) %, preset the specimen for 24 hours.

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