Page 36 - OHS, July/August 2020

PPE: HAND PROTECTION
The following table provides the transmitted forces for per- formance levels in the SI system as well as the corresponding English units.
Impact Examples
The following graphic provides examples of impact scenarios. These examples are for illustrative purposes only. Keep in mind that the contact area and hardness of the materials involved are different for each example. The goal here is to provide general or- ders of magnitude to serve as a frame of reference for ANSI/ISEA 138:2019 performance levels.
Remember that the dorsal impact glove standard measures transmitted forces measured after a portion of impact energy has been absorbed by the glove material being tested. The maximum impact forces generated with a metal-to-metal (no glove sample) impact in a drop rig is around 45kN (10,116 lbs-force). The big
question is: how much impact energy is required to break a bone in the hand?
Another challenging question! First, you have to define a frac- ture—I won’t get into that here. The ideal means of obtaining an answer to this question is to conduct laboratory experiments. The only laboratory option available is cadaver samples. Unfortunately, cadaver samples tend to come from older adults are not generally representative of a young, healthy industrial worker. Varying fac- tors like bone density, bone health, size and strength of surrounding muscles and connective tissues will significantly affect bone fracture potential. More research is required to adequately answer this ques- tion. Best guess (with many assumptions and caveats): minimum impact force to fracture phalangeal or metacarpal bones in an im- pact is between 3kN (680 lbs-force) and 5kN (1,124 lbs-force).
The ANSI/ISEA 138: 2019 dorsal glove impact standard can be a powerful tool to improve hand safety performance. End-users must carefully assess the appropriate impact performance level for their applications’ needs and solicit the expertise of an industrial hygienist or safety engineer.
Rodney Taylor, MS, MBA has over 20 years of experience in the safety industry. Rodney has worked as a researcher for the NASA Langley Research Center, held a variety of leadership roles with the DuPont corporation and Global Sales and Marketing Manager for Industrial PPE for D3O. He currently serves as Director of Sales, US for Watson Gloves. Rodney also serves as a Trustee of the Inter- national Safety Equipment Association (ISEA), Chair of the ANSI/ ISEA 138:2019 Work Group and former Vice-President of the Inter- national Glove Association.
30 Occupational Health & Safety | JULY/AUGUST 2020
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