GB/T 17794-2021Preformed flexible elastomeric foam thermal insulation (English PDF)

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.

4.1 Classification

4.1.1 According to the service temperature range of products, they are divided into.

4.1.2 According to the shapes of products, they are divided into boards (represented by B) and pipes (represented by G).

4.2 Marking of products

The order of marking is as follows. product name, type, shape, width (inner diameter)

× thickness (wall thickness) × length, veneer material, and this document number.

5.1 Appearance quality

Except for the section cut by the factory machinery, the surface shall have natural skin.

The surface of the product shall be flat, allowing fine and uniform folds, but there shall be no obvious defects such as blisters, cracks, and damage that affect the use.

5.4 Combustion performance

5.4.1 The oxygen index of CY-type products shall not be less than 32%, the oxygen index of DW-type and GW-type products shall not be less than 30%; the smoke density grade shall not be greater than 75.

5.5 Special requirements

5.5.1 Release of TVOC

When used indoors and there are environmental requirements, it shall not be greater than 0.50 mg/(m2 · h).

5.5.2 Anti-aging properties

When the products are used outdoors, the anti-aging performance test shall be carried out, and the test time shall be negotiated by both parties. After the test, the surface of the sample shall be free of cracks, pinholes, and obvious deformation, but slight wrinkling is allowed.

6.1 Conditioning

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).

6.5 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.

6.8 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.

6.10 Temperature resistance

6.10.1 Dimensional change rate

6.10.1.1 Carry out the determination according to the provisions of GB/T 8811, and test 3 specimens for each sample. The length of the tubular specimen shall be (100±2) mm, and measure the dimensions of the inner diameter and wall thickness of the product according to Appendix A.

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.

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) °C, 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.

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.

7.2 Batching and sampling

7.2.1 Batching

Group the products with the same raw material formula, the same production process, the same variety, and of stable and continuous production together into an inspection batch.

7.2.2 Sampling

7.2.2.1 Secondary sampling is adopted for the inspection of the appearance and dimensions, and the sampling plan is shown in Table 4, in which the batch size and the number of samples refer to the number of pieces of boards or pipes. The samples shall be randomly selected from the inspection batch, and the samples shall be able to represent the average quality of the batch.

7.3 Judgment rules

7.3.1 All properties shall be regarded as independent and judged by the rounded values of the determination results.

7.3.2 Judgment of appearance and dimensions shall be in accordance with the provisions of Table 4.