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Image Shield Name Description Standard Style Count
Headwear Mountaineers Helmet for Mountaineers The crown shock test subjects the helmet to 100 Joules force - twice as much energy as the EN397 crown test. Additionally it also has off crown, front, side and rear shock tests. The standard as the same penetration test to 29 Joules on the crown but additionally has an off crown penetration test. The harness systenm is designed to resist a tugging force applied by a 10Kg weight dropped over a distance of 175mm whilst attached to either the front or rear of the helmet. The harness is designed to withstand up to 500 Newtons force over a minimum of 2 minutes whilst remaining securely fastened. EN12492 : 2012 1
Headwear Safety Helmets Lateral Deformation EN397_2012 This standard applies to protective helmets for industry where the helmet is intend to protect a static user from the predominantly falling hazard. An impact test may be carried out to confirm suitability against lateral deformation this is a voluntary additional test. EN397 : 2012 4
Headwear Safety Helmets Impact / Shock Absorption Where helmets are of the type intended to protect a static user from predominantly falling hazards, a series of impact tests are carried out using a fixed headform, with a falling mass striker. The helmet under test is placed onto a suitably-sized (and dimensioned) headform, mounted on top of a load cell, which in turn is mounted to a rigid (and monolithic) base. A striker, in this case with a hemispherical surface, of a suitable mass (5 kg) is dropped onto the helmet from a specific height (1 metre). The force transmitted through the helmet is measured using the load cell beneath the headform, and recorded onto a graph. For a helmet to meet the requirements of EN 397, the maximum transmitted force, after suitable signal conditioning, cannot exceed 5 kN. Penetration Industrial helmets are tested to ensure they offer sufficient protection against sharp or pointed objects. The test is based on a method similar to the shock absorption test, in that a striker is dropped from a set height onto the helmet fitted to a fixed headform. However, in this case, the striker is a pointed cone (of mass 3 kg, dropped from a height of 1 metre), and rather than measure the transmitted force, the assessment is based on whether the striker makes contact with the headform underneath the helmet. This can be carried out using indicator material (e.g. plasticine or soft metal) on the headform itself, or by establishing electrical contact between the striker and headform (where if the striker contacts the headform, a circuit is complete which sounds an alarm). As with the impact testing, this is carried out on helmets pre-conditioned to high temperature, low temperature, water immersion and UV ageing. Design Requirements Most specifications for protective helmets include a number of requirements for the design of a helmet in addition to the specific performance requirements. These typically encompass the area of coverage provided by the helmet, as well as the field of vision afforded to the user when worn. They can also cover a number of ergonomics and safety-based requirements, such as clearance between the head and the shell of the helmet (particularly in the case of industrial helmets). Chin strap anchorage Helmets can only protect when retained on the head, therefore, a chin strap may be supplied to ensure retention in typical workplace conditions. EN 397 requires that either the helmet shell or the headband is fitted with a chinstrap or with the means of attaching one, i.e. anchorage points. Any chinstrap supplied must have a minimum width of 10 mm when un-tensioned and be attached either to the shell or to the headband. The strength of the strap anchorage(s) should be sufficient to enable any attached chin strap to hold the helmet on the head but not so great that the strap would become a strangulation hazard. In the method for measuring chin strap anchorage strength specified in EN 397 the helmet is mounted onto a suitably sized headform and the chin strap passed around an artificial jaw. A tensile force is then applied to the artificial jaw at a rate of 20N/min until the artificial jaw is released, due to failure only of the anchorage(s). The standard requires that the force at which this occurs shall be no less than 150 N and no more than 250 N. EN397:2012 18
Headwear Bumpcaps Bump caps are intended only to protect the wearer from static objects (e.g. walking into low ceilings or hanging obstructions). As such, impact tests are carried out similar to those required for industrial helmets, but using a lower energy level – a 5kg flat striker is dropped onto the helmet from a height of 250mm, with a maximum allowable transmitted force of 15kN. Impacts are carried out on the front and rear of the helmet, with the headform tilted at 30° and 60° to reflect the nature of any impacts likely in use. This test is carried out on several helmet samples, following pre-conditioning to high temperature, low temperature, water immersion and UV ageing. EN812 : 2012 13
Headwear for low voltage Where helmets are intended to be used in environments where there is the potential for contact with high voltage electrical potential (up to 1000Vac or 1500Vdc), helmets need to be tested for electrical insulation using EN 50365. This standard exceeds the requirements of the optional electrical resistance tests in EN 397 & EN 812 and the electrical requirements of EN 443. The method of test however is quite similar to the ‘wet helmet’ test in those standards – the helmet shell is filled with water then floated in a tank of water. Electrodes are placed in the water on the inside and outside of the shell, and a potential of 5000V (proof test) or 10,000V (withstand test) applied between the two. In the withstand test, the current passing through the helmet cannot exceed 3.5mA in order for the helmet to be acceptable, and in the withstand test, the helmet merely has to survive the application of the potential (i.e. not suffer puncturing or material breakdown). Prior to the test, helmets are subject to mechanical abrasion (sanding) and submerged in water for 24 hours, to remove any protective layers which may be worn in use. Helmets complying with this standard are allowed to include ventilation holes, provided they still provide protection against contact with the underlying headform by an IP3X probe. Any ventilation holes in the helmet are filled with electrician’s putty or adhesive to prevent water penetration during testing. EN50365 :2002 3
Headwear Safety Helmets Molten Metal Safety Helmets resists molten metal splash EN397: 2012 MM 3