The striker shall not contact with the headform.
188.8.131.52 Shock absorption test
In the shock absorption test the force of shock transmitted to the rigidly mounted helmet on a headform and the time elapse the shock are measured.
The base of the apparatus shall be monolithic and sufficiently large to offer full resistance to the effect of the blow. It shall have a mass of at least 500kg and shall be suitably installed to obviate the return compression wave. The headform shall be rigidly mounted so that the striking point is positioned vertically on the force transducer.
A striker having a mass of (5.0 ± 0.1) kg and a hemispherical face of 48 mm striking radius shall be positioned above the headform so that its axis coincides with the vertical axis of the headform. It may drop freely or in guided fall.
When the guided fall is selected, the retardation due to the guide shall be minimized. The impact force shall be measured by a non-inertial force transducer firmly attached to the base. The force transducer shall be so positioned that its axis is coaxial with the path of the striker. The load meter shall be able to measure a force up to 40 kN.
The system of measurement including the headform and its installation shall be of a frequency response performance which coincides with the frequency class (CFC) 600 specified in ISO 6487.
.3 Test procedure
One sample shall be tested in each pre-treatment condition specified in 184.108.40.206. Following test shall be completed within 1 min after removal of the sample helmet from the temperature conditioning chamber or water bath.
a) The sample shall be placed on the headform in the manner that the fitting means of helmet shall be adjusted to give largest space between the helmet and the headform.
b) The striker is allowed to fall on the safety helmet from a height of (1000±5) mm measured between the striking point of the safety helmet and the lower end of the striker.
c) The measurement shall be made by recording the waveform of the impact load transmitted to the headform.
The impact load to the headform shall not exceed 5.0 kN.
220.127.116.11 Test for radiant heat (EN443 paragraph 6.7)
Heat radiation of a known intensity from an infrared source is allowed to fall onto the outer surface of a helmet mounted on an instrumented headform. The temperature of the headform surface is measured. After the exposure to heat, the helmet shall be tested in accordance with 18.104.22.168 shock absorption test.
The principle of a suitable apparatus is shown in figure xx. The apparatus consist of:
- A bank of heaters
- A calibrated radiometer / calorimeter
- A wooden headform
- A set of temperature sensing elements
b) Bank of heaters
A heater or a bank of heaters is mounted with its radiating surface horizontal and facing downwards. The radiating surface shall be flat and its dimensions (250 ± 5) mm x (250 ± 5) mm.
The peak wavelength of the emitted heat radiation shall be between 2 μm and 3 μm. The intensity of radiation shall be uniform and shall be adjustable.
c) Calibrated calorimeter / radiometer
A calibrated calorimeter / radiometer, which has a measurement range of at least 10 kW/m2, is mounted on a movable and adjustable device with its sensing surface parallel to the bank of heaters and facing upwards. The center of its sensing surface shall be adjusted on the vertical axis of the heater.
A headform, specified in 22.214.171.124 shall be mounted on a movable and adjustable device. The test shall be one of the two points, L4 - L5, defined in figure xx corresponding to a 30 degree lateral inclination of the headform to vertical.
e) Temperature sensing elements
Three calculated temperature-sensing elements (preferably consisting of thermocouples mounted on circular copper discs of (7 ± 1) mm diameter and thick ness of (0.2 ± 0.02) mm) are secured by electrically insulating adhesive to the headform surface. Their center shall be within 5 mm of a transverse vertical plane passing through the test site, at the following positions:
i) on the central vertical axis
ii) on the AA' plane
iii) mid-way between position i) and ii) measured along the headform surface/
Note 1; suitable ISO or CEN standards should be selected, when available, for these calibration requirements.
Note 2; Surface adjacent to this test equipment should not reflect the radiant heat falling on them or allow passage of measurable quantities of heat into the test equipment area.
Note 3; The effects of draughts should be minimized.
Note 4; All supports for headform and radiometer/calorimeter should be of low heat conductivity and reflectivity.
a) Mount the helmet on the headform. Put the helmeted headform in the test position under the bank of heaters. Measure the distance from the radiating surface.
b) Move the helmeted headform aside to allow setting of the radiant heat intensity.
c) Move the radiometer/calorimeter under the heater bank until their vertical axes are coincident and adjust the distance from the radiating surface in compliance with the distance measured in a). Adjust the heater controls until the flux intensity measured is (7 ± 1) kW/m2, Remove the radiometer/calorimeter.
d) Replace the helmeted headform in the position determined in a) and expose the helmet to the radiant heater for (180 ± 2) s. Record the temperature.
e) After removal, allow the helmet to cool to ambient temperature for at least 4h. After inspection, impact the helmet once on the exposed lateral point, using the procedure defined in 126.96.36.199 except the conditioning pre-treatment.
The test result shall comply with the requirement of 188.8.131.52.
184.108.40.206 Flame resistance test
A standard flame is applied to the outside of the helmet and tendency to drip, glow or to continue burning after removal of the flame is observed.
The apparatus consist of a supply of gas, a gas burner, a pressure control device and pressure gauge. The gas burner shall have a bore diameter of (8,5 ± 0,5) mm and adjustable air vent.
a) Adjust the gas pressure to (3450 ± 50) Pa and the air vent of the burner so that the blue cone is clearly defined, although turbulent, and is (45 ± 5) mm long. The outer flame shall be entirely free of visible yellow area.
b) Support the burner at an angle of (45 ± 10) degree to the vertical.
c) Support the complete helmet, so that at the point to be tested the plane tangential to the surface is horizontal. Maintaining these angles, apply the outer part of he flame to the point of test for (10 ± 2) s.
d) The test point shall be any suitable point inside the areas defined by the intersection of the surface of the shell with:
- A 100mm diameter cylinder centered on the vertical axis of the helmet.
- A 200mm diameter cylinder centered on the vertical axis of the helmet.
- Planes parallel to the sagittal plane of the helmet and 25mm distant from this plane.
There shall be no holes produced in the helmet. After the removal of the flame, there shall be no flaming on the helmet, or if flaming occurs, the flaming time shall not exceed 5 s at any points of test.
5.5.2 Requirements for neck plate
220.127.116.11 Materials of the neck plate shall conform to clauses 5.2.1, 5.2.4, 5.2.5 and 5.2.6.
18.104.22.168 The neck plate shall conform to clauses 4.4, 4.5, 4.7 and 4.11.
5.5.3 requirements for hood lens
22.214.171.124 When tested in accordance with the method given in Annex E, there shall be no holes produced in the hood lens.
126.96.36.199 The lens shall stay in normal condition and shall show no signs of damage or deterioration when tested in accordance with the method given in Annex C.
188.8.131.52 The lens shall be tested in accordance with clause 5.2.5 and not melt, drip, separate. or ignite. Immediately after this test the lens shall be immersed in water at ambient temperature, and shall stay in normal condition and shall show no signs of damage or deterioration.