We want to assist you in understanding how cut
test methods are performed and calculated into
a Cut Level Rating. Currently the cut resistance
of protective gloves is assessed using two test methods:
- For the European market, the mandatory standard
is EN 388 (first version: 1994 – current version: 2004).
- In the U.S. market, the standard is ASTM F1790
(first version: 1997 – current version: 2005). This
method was adopted by ISO in 1999 as an international
standard: ISO 13997.
EN method
EN method uses a circular blade with a constant
pressure of 5 N (~ 500 grams) applied to the blade.
The blade makes an alternating horizontal movement
over 50 mm (2 inches) of the glove material and
rotates in the opposite direction of the movement.
This results in a sinusoidal blade speed with a maximum
of 100 mm/second.
The value measured is the number of cycles it takes
to cut the material. A cotton reference material is used
to control the sharpness of the blade. Test on the cotton
material is performed before and after test on glove
material, then the average value of cycles for the cotton
material (Cn) is calculated. This value is correlated
with the value obtained for glove material (Tn) using
the following equation: In = (Cn + Tn)/Cn, where
“In” is the index value for the test sequence. Index
value is a number without unit and is also called “
cut
index”. Five test sequences (cut on the reference/cut
on glove material/cut on the reference) are performed
and the average index value I is calculated.
EN 388 defines five levels of cut resistance with
level 1 being the least and level 5 being the most cut-resistant
gloves:
A drawback of the EN test method is that it is not,
for the most part, representative of the cut risks end-users
are exposed to in industrial workplaces:
- the 5 N (~ 500 grams) pressure applied on the
blade is too low;
- the alternating displacement of the blade makes
the contact time with the glove sample very short.
Moreover, EN 388 is not suitable for high cut resistance
materials. High cut resistant materials dull the blade
quickly by the numerous alternating movements required
to cut the sample, thus results are overestimated.
ASTM method
ASTM method uses a 50 mm (2 inch) length straight
blade, which is moved one time across the glove material
under a given load, at a constant speed of 2.5 mm/s.
The test result is expressed as the load required to cut the
glove material after the blade travels 20 mm (3/4 inch).
This load is called
rating force (unit of grams
force), with a larger load indicating a higher cut resistance.
A series of tests are performed with different loads
(minimum three) and blade displacements necessary to
cut the sample are recorded. From this data, load vs. distance
curve is plotted and the rating force is determined.
ASTM method is more representative of workplace
conditions vs. the EN method:
- The straight blade cuts the material in a single
stroke; which is the mechanism involved when there
is a risk of laceration with a sharp edge such as knife
or box cutter;
- Various weight loads are applied to the blade as
it travels across the glove material.
ASTM F1790 does not specify any level of performance.
The classification for cut resistance is provided
by ANSI/ISEA 105-2005 standard. ANSI/ISEA
refers to the previous version of ASTM test method
(ASTM F1790-97) where the reference displacement
for the blade was 25 mm (1 inch) vs. 20 mm (3/4
inch) for the current version ASTM F1790-05.
It is worth noting both cut test methods use control
weight, not sudden force, which is very often the case in
the workplace. The current ASTM test method will provide
a reliable glove selection component when choosing
cut protective gloves to protect workers in your facilities.
Moderate/standard protection: Level 1
to 2 according to ANSI/ISEA cut standard. These woven
gloves allow the skin to breathe more easily. They are
recommended for continuous use in situations where
the objects handled are only mildly abrasive, i.e. using a
safety knife or handling untrimmed sheet metal.
Heavy duty/high-performance protection:
Level 3 to 5 according to ANSI/ISEA cut
standard. These gloves have been coated or are multi-layered
to improve their resistance to frequent contact with
sharp or abrasive objects. As a result, they have a longer
service life, i.e. repeated handling of heavy and rough,
sharp-edged parts.