GB/T 20105-2026Coated fabrics for air ducts (English PDF)

5.1 Specifications and Dimensions

5.1.1 Width Tolerance The width of the flat-width coated fabric shall be determined by negotiation between the supplier and the buyer, and the tolerance shall be 0mm~10mm.

5.1.2 Diameter and Tolerances The recommended diameter and tolerances for tubular coated fabrics should conform to the specifications in Table

1.Other diameters and tolerances shall be determined through negotiation between the supplier and the buyer.

5.1.3 Thickness The thickness of impact-resistant coated fabric should not exceed

1.2 mm; the thickness of non-impact-resistant coated fabric should not exceed

0.8 mm.

5.2 Appearance Quality

5.2.1 The base fabric should be free of breaks and creases; the coated fabric should be free of coating peeling and missing covering film.

5.2.2 On a 1m^2 area of coated fabric, the presence of non-detachable covering film lumps, non-broken bubbles, and areas not exceeding 3mm in diameter is permitted. Impurities no larger than 1 mm^2 should not exceed 5 in total, of which no more than 2 should be non-broken air bubbles.

5.2.3 It should be odorless, and the surface should be uniform in color, clean, dry, and free of obvious oil stains.

5.3 Physical and mechanical properties

5.3.1 Tensile force The tensile strength should meet the requirements of Table 2.

5.3.2 Tear strength The tear strength should conform to the specifications in Table 2.

5.3.3 Adhesion The adhesion should conform to the specifications in Table 2.

5.4 Flame retardancy Flame retardancy should meet the requirements of Table 3.

5.5 Antistatic properties The surface resistivity of the flat-width coated fabric (top and bottom surfaces) and the surface resistivity of the tubular coated fabric (outer and inner surfaces) should not exceed [value missing]. 3×108Omega.

5.6 Heat resistance After the heat resistance test, the surface of the coated fabric should be free of cracks and stickiness.

5.7 Cold resistance After the cold resistance test, the surface of the coated fabric should be free of creases, cracks, or other defects.

5.8 Impact resistance After the impact resistance test, the coated fabric should not show any signs of puncture.

5.9 Smoke density The maximum specific optical density measured after the coated fabric is burned should not exceed 650.

5.10 Smoke Toxicity Index The toxicity index of the flue gas measured after the coated fabric is burned should not be greater than 0.64.

5.11 Limits for Lead and Arsenic The lead and arsenic content of the coated cloth should not exceed 1000 mg/kg.

6.1 Specifications and Dimensions

6.1.1 Width Tolerance Lay the coated fabric flat on a smooth, level measuring platform and measure it using a measuring instrument with a graduation of no more than 1 mm. Measure at both ends and the middle. Measure once, take the arithmetic mean as the width of the coated fabric, and round it to 1 mm.

6.1.2 Diameter and Tolerances Lay the tubular coated fabric flat on the measuring platform, measure the width of the coated fabric according to 6.1.1, calculate the diameter of the tubular coated fabric, and round it to the nearest whole number. 1mm.

6.1.3 Thickness Proceed according to the provisions of HG/T 3050.3.

6.2 Appearance Quality Use measuring tools and visual inspection or sensory inspection methods to check.

6.3 Physical and mechanical properties

6.3.1 Test Environment Conditions The test shall be conducted in an environment with a temperature range of 18°C to 29°C. Samples should be conditioned under the same conditions for at least 2 hours before the test.

6.3.2 Tensile force The sample width was (50±0.5) mm, with 5 samples each in the warp and weft directions, and the test was conducted according to Method 1 of HG/T 2580-2022. Calculate the arithmetic mean of the tensile forces of 5 warp specimens and the arithmetic mean of the tensile forces of 5 weft specimens as the result, and round it to the nearest integer. 1N.

6.3.3 Tear strength Proceed as specified in Appendix A.

6.3.4 Adhesion Prepare the specimens according to method 2 in HG/T 3052-2022, trim the specimen width to (25±0.5) mm, and prepare 5 warp and 5 weft specimens each. Each test shall be conducted according to the provisions of HG/T 3052-2022.The test shall be stopped when the stroke is not less than 100mm or other termination conditions are met, and the results shall be recorded. For each sample curve, the median value within the 30%-100% stroke range was recorded as the adhesion force of that sample. Adhesion forces of five meridional samples were calculated separately. The arithmetic mean of the force and the adhesion force of the five latitudinal samples was used as the result value, and rounded to 1N.

6.4 Flame retardancy Proceed according to MT/T 113.The sample thickness is the actual thickness of the coated fabric, and the ignition time is determined by igniting the sample. The test is accurate, but the ignition time of the sample in the alcohol torch burning test should not exceed 15 seconds, and the ignition time of the sample in the alcohol lamp burning test should not exceed 20s.

6.5 Antistatic properties Perform according to MT/T 113.The sample thickness is the actual thickness of the coated fabric.

6.6 Heat resistance Proceed as specified in Appendix B.

6.7 Cold resistance Proceed as specified in Appendix C.

6.8 Impact resistance

6.8.1 Test Apparatus The testing apparatus should have a frame and guide rails to allow the weight to fall freely in a vertical direction and to prevent secondary impacts on the specimen. (Weight impact) The head is made of steel, with no protrusions, dents, scratches, or other defects on the surface. The hammer body weighs 5.8kg~6.2kg. A schematic diagram of the hammer punch dimensions is shown in Figure 1. The shape and material of the remaining parts of the hammer are to be designed independently. The test area of the clamp is a circle with a diameter of 160mm~200mm, which should be able to hold the sample firmly. The clamping part can be corrugated without affecting the performance of the sample, and the sample should not have relative displacement during the test. See Figure 2 for a schematic diagram of the clamp. The unit is millimeters.

6.8.2 Sample Preparation At least 50 mm from the edge of the coated fabric, randomly select 3 points, and cut 3 samples conforming to the specifications of the clamp with each point as the center. The sample should be able to be clamped by the clamp.

6.8.3 Test Procedure

6.8.3.1 The specimen is fixed with a clamp, and the center point of the specimen is on the same vertical line as the hammer punch.

6.8.3.2 Adjust the bottom of the hammer punch to a height of 2m ± 10mm from the sample surface and release it.

6.8.3.3 Impact each of the three specimens individually, with each specimen subjected to only one impact.

6.8.3.4 After the test is completed, observe and record whether each sample is punctured.

6.9 Smoke density Perform the procedure according to GB/T 8323.2.Cut three samples with dimensions of (75±1) mm × (75±1) mm from the coated fabric, with a thickness of... The degree refers to the actual thickness of the coated fabric. The maximum specific optical density was measured under a radiation irradiance of 25 kW/m^2 and a non-ignition mode. This test was repeated three times. Test, take the arithmetic mean, and round to 1.

6.10 Smoke Toxicity Index Three samples with dimensions of (75±1)mm × (75±1)mm were cut from the coated fabric, with the thickness being the actual thickness of the coated fabric. According to GB/T 8323.2, under a radiation irradiance of 25 kW/m^2 and a non-ignition mode, a smoke density box and an online Fourier transform infrared gas analyzer are used. The analyzer continuously collects flue gas, with each collection lasting no less than 6 minutes. The maximum concentration of each gas listed in Table 4 is measured, and the concentration is calculated according to formula (1). The toxicity index of flue gas was determined by repeating the test three times, taking the arithmetic mean, and rounding it to 0.01.

6.11 Limits for Lead and Arsenic Proceed as specified in Appendix D.

7.1 Factory Inspection

7.1.1 Products shall be inspected batch by batch by the quality inspection department of the manufacturing enterprise, and can only be shipped out after passing the inspection and being issued a certificate of conformity.

7.1.2 Factory inspection shall be carried out in accordance with the factory inspection items specified in Table 5.

7.2 Type Testing

7.2.1 Type testing shall be conducted in accordance with the type testing items specified in Table 5.

7.2.2 Type testing shall be conducted under any of the following circumstances.

a) During the trial production and evaluation of new products;

b) When transferring production of old products to another factory;

c) When significant changes in materials or processes may affect product performance;

d) When production resumes after a product has been out of service for more than three years;

e) When the factory inspection results differ significantly from the previous type inspection results;

f) Normal production, conducted once every five years;

g) When a quality supervision or management agency requests a type test.

7.3 Sampling Method

7.3.1 Sampling method for factory inspection Products should be sampled batch by batch, with a minimum sample size of 3m^2.

7.3.2 Sampling Method for Type Testing Randomly sample from products that have passed factory inspection, with a sample size of no less than 6m2.

7.4 Judgment Principles If all inspection items pass, the batch of products is deemed qualified; if any inspection item fails, the batch of products is deemed unqualified.