This standard specifies the test methods and equipment for the physical and technical properties of industrial helmets. This standard applies to industrial helmets and helmets used in special places as specified in GB 2811. GB 2812-1989 Test methods for helmets GB2812-1989 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Test methods for helmets
GB 2812 - 89
Replaces GB2812-81
Part 4 Standards and specifications
This standard adopts the international standard IS03873-1977 "Helmets for industrial use" by reference. 1 Subject content and scope of application
This standard specifies the test methods and test equipment for the physical and technical properties of helmets for industrial use. This standard applies to helmets for industrial use and helmets for special places specified in GB2811. 2 Reference standards
GB1410 Test methods for solid electrical insulating materials, insulation resistance, volume resistivity and surface resistivity GB2811 Helmets
3 Test samples
3.1 Quantity
The test samples should be helmets for sale. The quantity should be determined according to the test items required for the classification of helmets, and two helmets should be added as spares. The required samples are shown in Table 1.
Select one of the above conditions that is most unfavorable to the material performance
3.2 Treatment before the test
3.2.1 High temperature treatment
Punch resistance
Electrical insulation
Antistatic
Lateral rigidity
Put the helmet in a heating box at a temperature of 50℃±2℃. For helmets used in coal mines, the temperature is 35℃±2℃. Keep the temperature constant for 3h. After taking it out, complete the test within 1min. 3.2.2 Low temperature treatment
1024 Compilation of laws, regulations and standards for construction safety Put the helmet in a low temperature box at a temperature of -10℃±2℃. For helmets used in low temperature workplaces, the temperature is ~20℃±2℃. For helmets used in coal mines, the temperature is 0℃±2℃. After keeping the temperature constant for 3h, complete the test within 1min. 3.2.3 Water treatment
Put the helmet on a fixed bracket, spray the helmet surface with water at a flow rate of 1L per minute for 2h, take it out and wipe it dry and then test it immediately.
4 Impact absorption performance test
4.1 Test equipment (as shown in Figure 1).
1 Concrete base; 2-base; 3 piezoelectric force sensor; 4-head mold: 5-steel hammer; 6-safety helmet; 7-force sensor supporting device; H-impact distance Figure 1 Schematic diagram of impact absorption performance test (using piezoelectric force sensor) 4.1.1 Base: concrete base with a weight of not less than 500kg. 4.1.2 Head mold (see Appendix A of GB2811).
4.1.3 Impact bench: a test bench that can lift and release the steel hammer and make it fall freely or with guidance. The impact speed of the guided steel hammer should be equal to the free fall speed. 4.1.4 Steel hammer: symmetrical and evenly hooked, made of 45# steel, weighing 5t0.01kg, hammer head is hemispherical, with a diameter of 96mm
4.1.5 Force sensing device
a. Force sensor (piezoelectric, resistance strain, semiconductor strain, etc.) with a measurement range of 0~30000N and a frequency response of 5~1000Hz
b. Force sensor supporting parts: parts that match the force sensor and play the role of guiding, transmitting force, connecting the head mold and the base.
4.1.6 Base: a steel base for installing the force sensor, supporting the head mold and the force sensing device. 4.1.7 Amplifier: an instrument that matches the force sensor and amplifies the signal. 4.1.8 Recording and display instrument: an instrument that can record and display the size of the amplified signal. 4.2 Test block diagram
4.3 Test method
Part 4 Standards and specifications 1025
Force sensor→amplifier→recording and display instrument Place the headform, force sensor and base vertically on a solid base. The force sensor is installed between the headform and the base (as shown in Figure 1). After the lining of the helmet is adjusted to the appropriate position, it is put on the headform. A steel hammer is dropped freely or guided from a height of 1m (the distance from the bottom of the hammer to the helmet). The motion trajectory of the center of gravity of the steel hammer should coincide with the center line of the headform and the sensitive axis of the sensor. The impact force on the headform is measured by the recording and display instrument. 5 Penetration resistance test
5.1 Test device
5.1.1 Headform: Add conductive material to the upper surface of the headform in 4.1.2. 5.1.2 Impact bench: See 4.1.3.
5.1.3 Steel cone: Made of 45# steel, weight 3+0.05kg, cone angle 60°, cone tip radius 0.5mm, cone minimum length 40mm, cone tip hardness HRC45.
5.1.4 Electric contact display device: A device that can display electrical signals. 5.2 Test method
The head mold is placed vertically on the base, so that the head mold, the steel cone and the electric contact display device form an electric closed loop (see Figure 2). Use a 3kg steel cone to drop freely or with guidance from a height of 1m to puncture the safety helmet. The point where the steel cone hits the helmet should be at the weak part within Φ100mm of the center of the top of the helmet. Observe the electric contact display device after puncture. Electrical contact display device
1—steel cone; 2—safety helmet; 3—head mold; H—impact distance Figure 2 Schematic diagram of puncture resistance test
6 Electrical insulation test
6.1 Test device: AC transformer; voltmeter; ammeter; test water tank. Place the safety helmet in a 3g/L, 10℃～30℃ sodium chloride solution for 24h, take out the hat and wipe it clean. Then place the cap shell facing down in a test water tank filled with sodium chloride solution, and inject sodium chloride solution into the cap shell until the water surface is 30mm away from the edge of the cap (see Figure 3). Connect the two high-voltage output terminals of the test transformer to the solution in the water tank and the cap shell respectively, use a voltmeter to observe the voltage at the output terminal of the transformer, increase the voltage to 1200V within 1min, and keep it for 1min to measure the leakage current. 7 Flame retardant test
7.1 Test device: 2kg gasoline blowtorch.
7.2 Test method: Lay the helmet flat, use No. 70 gasoline, adjust the flame length of the gasoline blowtorch to 230mm, and put the flame of the gasoline blowtorch on the water surface.
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Voltmeter
Amperemeter
Test water tank
Figure 3 Schematic diagram of electrical insulation performance test
The flame is aimed at the part below 100mm of the top of the helmet at a 45° direction, and the helmet shell is burned at a distance of 130mm for 10s (see Figure 4). After the flame is removed, the afterburning time of the helmet shell is recorded.
Figure 4 Schematic diagram of flame retardancy test
8 Lateral rigidity test
Figure 5 Schematic diagram of lateral test
8.1 Test equipment: 1960N pressure testing machine. 8.2 Test method: At room temperature, place the helmet sideways between two flat plates, with the brim extending out of the flat plates but close to the bottom edge of the cap shell. The press applies pressure to the helmet through the flat plates (see Figure 5). First, add 29.4N and hold for 30s. Measure the distance between the two plates. This distance is called the initial value. Then increase the load by 98N per minute until it reaches 421.4N. Hold for 30s. Measure and calculate the difference between the distance between the two plates and the initial value at this time, which is the maximum deformation value. Then reduce it to 24.5N, and then increase it to 29.4N. Hold for 30s. Measure and calculate the difference between the distance between the two plates and the initial value, which is the residual deformation value. 9 Antistatic performance test
9.1 Test equipment: 500V high resistance meter.
9.2 Test method: Place the helmet in an environment with a temperature of 20℃±5℃ and a relative humidity of 50%±5% for no less than 24h. Use conductive paint that does not affect the surface resistance to draw two parallel lines on the flatter part of the helmet to be tested as measuring electrodes. The electrode length is 100±1mm, the electrode width is 1m, and the electrode spacing is 10±0.5mm. Connect the measuring ends on the high resistance meter to the reasons for inspection respectively until it is less than 10%, and record the readings. The average of the two measurement readings is the actual measured surface resistivity.
10 Rules for the use of standard measuring instruments
Part IV
Standards and specifications
10.1 The standard measuring instruments used in this standard cannot be used for other purposes. When not in use, they must be covered with protective covers. The instruments must be calibrated by the local standard measurement department every year
before they can be used. Additional notes:
This standard was proposed by the Ministry of Labor of the People's Republic of China. This standard was drafted by the Beijing Institute of Protection Science. The main drafters of this standard are Li Guangzong, Chen Jian, Yang Wenfen, and Xu Shijing.
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