Determination of the projectile resistance of personal protective equipment for use on multi-blade circular sawing machines

Status:

completed 01/2026

Aims:

Multi-blade circular wood sawing machines are generally operated at high cutting speeds of up to 80 m/s. Modern manually fed multi-blade circular sawing machines typically feature guards and safety systems designed to prevent kickback of wooden boards or planks and flying debris in the form of splinters. Owing to these machines’ design, however, neither the infeed nor the outfeed can be fully safeguarded. At the infeed end of the machine, in particular, a residual risk exists of debris in the form of splinters being propelled in the direction of the machine operator. This debris, with a velocity typically similar to the cutting speed, can cause serious injuries should it hit the machine operator’s torso or abdomen. Puncture wounds present the greatest hazards. Injuries from blunt force trauma also occasionally occur, however: these can lead in turn to severe bruising or broken ribs. The neck and head of the operator lie outside the scatter range of the flying debris and are therefore not considered; accidents in which operators suffered head or neck injury are not known.

For serious puncture injuries to be avoided, it is essential that machine operators wear personal protective equipment (PPE) in the form of a splinter-proof protective apron. The concept of a splinter-proof protective apron was formulated by the DGUV’s Subcommittee Woodworking and Processing, and describes the apron’s composition but without stating technical information such as the thicknesses and qualities of the materials used. DGUV Rule 109-606 requires protective clothing in the form of a splinter-proof protective apron to be worn at the infeed of the machine. It defines the splinter-proof protective apron as a leather apron reinforced with woven wire mesh in the abdomen/torso area.

According to members of the DGUV’s Subcommittee Woodworking and Processing, this apron has failed to meet with wide acceptance, owing to its high weight and stiffness. As a result, it is rarely if ever worn by workers. Furthermore, this PPE’s resistance to projectiles in the form of flying debris has never been determined.

Activities/Methods:

Tests were carried out in a pneumatic ballistic testing facility to test the projectile resistance of aprons and materials that appeared suitable for use as PPE or for its manufacture. Particular attention was paid to materials of low weight, which are thus easier to wear, but which also satisfy the requirements presented by the impact energy of the projectiles. Wooden projectiles with a wedge tip formed by two symmetrical surfaces were fabricated for the test. The selected test samples were fired at with projectiles with a mass of 100 g and a velocity of 75 m/s (both based upon DIN EN ISO 19085-1:2021). In addition to the samples’ projectile resistance, the projectiles’ penetration depth in ballistic clay was also determined to permit assessment in a further step of the risk of trauma in the abdominal area. The limit for the deformation depth in the ballistic clay is < 20 mm, based on the guidelines of the VPAM, the association of test centers for attack-resistant materials and constructions. A suitable test method (final report) for determining projectile resistance was described and a corresponding test specification was formulated.

Results:

The study demonstrated that in the configurations studied, textile, leather-based and plastics-based materials generally failed to provide adequate protection against the wooden projectile at the target test velocity of 75 m/s. Single-layer aprons in particular, but also aprons reinforced in the abdomen area, were fully penetrated by the projectile even at significantly lower velocities. Only multi-layer, aramid-based textiles provided demonstrable protection, but still failed to meet the VPAM criterion of a maximum permissible deformation depth of 20 mm. Of all the samples tested, aluminum alloys with enhanced strength properties (EN AW-7075 T6) exhibited the best projectile resistance. Based on the present study, the development of new protective aprons is expedient, in consideration of the cost-protective action-acceptance matrix described in the introduction. Building on the findings of this study, textile materials could be studied further in a follow-up project, particularly regarding the depth of penetration in the ballistic clay. Owing to their low weight, these materials offer high potential for forms of protection that are easy and comfortable to wear. In addition, protective vests with inlays of suitable aluminum sheet should be considered, and their performance evaluated by means of identical ballistic tests.

A test specification is currently being drawn up for testing the projectile resistance of protective materials for use by operators of multi-blade circular sawing machines. Once it has been finalized, the IFA will be able to offer and conduct such tests.

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