High performance cut-resistant fabrics are manufactured in many forms and for a variety of purposes, including protective clothing and the secure covering of assets and personal belongings.
In most cases, any risk from severe cutting hazards should be removed from the work activity. However, some cutting hazards often cannot be removed due to the nature of the job, hence the use of cut-resistant clothing (a type of Personal Protective Equipment) should, therefore, always be considered where there is a realistic and identifiable risk of being accidentally cut, or in other cases being slashed by an aggressive member of the public or detainee.
Most minor cut incidents occur to the hands, simply because these are normally the parts of the body closest to the operation involving a sharp piece of metal or glass within industry sectors, or involving a knife, broken bottle or other type of edged weapon within homeland security sectors.
Other parts of the body can usually be protected by latest industrial type of cut resistant clothing or ‘body armour’ related slash resistant clothing for homeland security applications. Something that has been designed and developed over the past years in order to effectively help protect homeland security professionals e.g. prison or law enforcement officers from rapid blood loss following the slashing and penetrating of main arteries by a hostile and out of control individual.
Incidents such as the extremely brutal and almost fatal assault on prison officer Craig Wylde at Frankland High Secure Prison (UK) in March 2010 have been widely reported in several countries around the world. Outrageous assaults like this have made the potential use of cut or slash resistant fabric a serious cause for discussions in health and safety departments everywhere.
Where technical fabrics used for such type of protective clothing have a high resistance to cutting, a method specified in the widely respected ISO 13997:1999 is being used. It has become the real benchmark for the testing of high performance cut resistant fabrics.
The ISO 13997:1999 method uses a straight blade drawn across a piece of a test fabric until cut-through takes place. The principle of this test is to vary the load required to be applied to the blade in order to facilitate cut-through in a known distance.
This test machine used for this standard and test includes a straight blade of a precise level of sharpness, fitted to a carriage, which is capable of only a horizontal movement to draw the blade across the sample. The fabric sample is mounted on a curved surface. In turn, this is placed on top of a series of devices in order to apply a force from below the sample holder onto the blade, which simulates a force or weight being placed on top of the blade itself. The blade is drawn across the sample at a fixed speed, with the distance travelled until cut-through being recorded.
The cut-through is identified when an electrical contact is being made between the blade itself and the fabric holding device.
The test procedure begins by carrying out a number of cuts using a variety of weight is applied to the blade to gain a suitable range of cut lengths. This is, typically, five cuts in the range of 5-15mm, five cuts in the range of 15-30mm and five cuts in the range of 30-50mm.
From a graphic that will be part of the official test report, an estimate can be gained for the applied load necessary to gain a 20mm stroke length before cut-through.
Using this estimate, a further five cut tests are carried out. If the average of these five cuts is within a suitable tolerance from 20mm, a further estimate is taken from the new graphic and recorded as the final result.
If the average of the five cuts is outside the tolerance, the new estimate is used for a further five cuts. The final estimate from this third graphic then becomes the final test result. The test result is based on the estimated force required to generate a 20mm stroke length. The result is stated in Newton.
The main purpose of the ISO 13997:1999 cut resistance test is to provide data for comparison between fabrics (the larger the force, the higher the cut resistance). It allows firms to clearly highlight the level of cut resistance their fabric is offering, allowing any uniform, tactical apparel or any other type of manufacturing facility to make an informative decision what fabric is the most appropriate one for their chosen application. Is widely considered that the ISO 13997:1999 stand and test method is generally more accurate for high levels of cut resistance. However, having said this it is also significantly more time-consuming and costly to carry out in comparison to tests.
Source by Robert A Kaiser