工業頭盔 EN397標準
工業頭盔 EN397標準
5kg的半球形表面的撞擊器從特1公尺高度下落到頭盔上，最大傳輸力不能超過5
Kn。
重量為3kg是尖的錐體，從1公尺的高度落下，不破裂，可以保護頭部。
頰帶在的最小寬度必須為10毫米，並連接到外殼或頭帶上。
EN
397: 2012
Industrial 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. This test is carried out on
several helmet samples, following pre-conditioning to high
temperature, low temperature, water immersion and UV ageing. There is
also the option to expand the temperature range for the
pre-conditioning if claimed by the manufacturer.
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.
Optional Tests
EN
397 includes a number of optional test on helmets where additional
protection is claimed. Helmets can claim protection against very high
or very low temperatures, splashes of molten metal, electrical
voltages up to 440 V, and lateral deformation. Each of these
categories include tests to prove the helmet’s suitability for
protection against these hazards.
0 意見:
張貼留言