EN388 Coup Test is conducted with a rolling circular blade (think Pizza Cutting wheel) which rolls back and forth upon the same section of “Test sample” until cut through is achieved. A plain sample material (typically cotton canvas) is introduced to the test process to act as a “Reference sample” measurement for cutting wheel sharpness. This “Reference sample” is cut tested before and after the C.R “Test sample” to gauge the cutting wheel blade surface dullness.
From this C.R testing a material performance “Index” is recorded as a ratio of the number of cycles (passes back and forth) recorded for the “Test sample” to cut through compared with the “Reference sample”. The Coup test provides a rating of 5 various Cut Performance levels (1 being the lowest with 5 as the highest).
The testing method utilises the same downward pressure (5 Newtons), speed and surface contact length of travel on all materials tested. It is considered that higher C.R materials (containing Glass fibre or fine stainless-steel filaments) will contribute to a blunting of the rolling circular blade edge during the duration of the test procedure.
Consequently, a somewhat questionable result or C.R variable may exist in gloves considered as Highly Cut Resistant (In particular, EN388 cut level gloves carrying a rating of 4 or 5). These top end Index gloves are the commonly selected gloves for many when working in higher risk cut hazard environments, so an improved C.R test regime has been introduced to better address performance characteristics of the materials.
Article compiled by Protective Industrial Products (Australia)