by: Rob Shaul; Andy Rampp; Mike Harostock and Adam Scott
In two weeks we’ll be completing a study to compare the Mission-Direct grip and dexterity performance of popular structural firefighting gloves, and are seeking input.
Gloves are the most commonly complained about piece of equipment used by firefighters. Among the biggest criticisms are their lack of dexterity, inadequate grip and bulkiness. (1).
Study Objectives
1) Develop Mission-Direct grip and dexterity tests for firefighting gloves.
2) Identify the best performing glove of popular models to inform fire/rescue athlete for immediate purchasing decisions.
3) Explore glove design issues and solutions from other occupations (commercial fishing, welding, etc.) to identify possible improvements for firefighting gloves.
Gloves We’ll Test
Lion Fire Gloves Commander
Pro-Tech 8: Fusion Structural
Shelby FDP Koala/Core
Firemaster 4
Dragon Fire Alpha-X
How did we select these?
First, we asked 3 full time firefighters who we’ve worked with on projects before.
Second, we contacted to popular firefighter supply websites, allhandsfire.com, and thefirestore.com, told them we were conducting the study, and asked for their 3-5 top selling structural firefighting gloves. We combined the two lists and purchased the five which were shared, and we could find for sale.
What Input Do We Need?
We need to identify mission-direct grip and dexterity tests, and ask fire/rescue athletes to help. Prior research (see below) have used laboratory-based tests, but we don’t feel these were mission direct.
In speaking with the firefighters we know well, we understand the gloves must be tested dry, and soaked fully through (wet). One firefighter commented that he noticed grip issues primarily with wet gloves during a fire overhaul.
Grip strength – we are looking for something which closely mimics the most common demands of the F/R athlete, possible handling a wet, charged hose or carrying a heavy piece of equipment to or from a fire. We definitely know we need to measure both dry and wet grip strength, but we are looking to you for the exact means.
Dexterity – we know that there are times when F/R athletes will actually remove their protective gloves in order to work around their dexterity issues. The three most cited issues are: 1. Manipulating a radio, 2. Handling hydraulic rescue couplings and 3. Starting chain saws (1). So, if we are going to test dexterity we would ideally have a test which closely resembles these demands, but is easily repeatable and universal.
How can you help?
Please help us identify common firefighting tasks where grip and dexterity is a common issue. Are there tasks which require you to consistently remove your gloves to complete? Are there tasks where grip fatigue causes you to have to stop and rest, before continuing on?
We’d appreciate any input/suggestions you can provide. Please email adam@mtntactical.com.
Previous Research
Below is a basic outline of the research we reviewed concerning firefighter gloves, dexterity and grip strength.
We know that firefighter gloves come in many shapes, sizes and designs. The two most commonly used designs are the 2-D glove (Gunn cut) and the 3-D glove (Fourchette design) (1). There are also three different thumb designs commonly found in firefighter gloves (5): Straight, Winged and Keystone.
In addition to these variables, firefighter gloves also come with a variety of back and front shell materials, moisture layers, thermal layers, and additional layers. Based on the options we found in the studies we reviewed, all together this gives us at least 18,816 glove permutations. [Glove Designs (2) x Thumb Designs (3) x Front Shell Materials (7) x Back Shell Materials (7) x Moisture Layer Material (4) x Thermal Layer Materials (8) x (Additional Layers (2)]. Obviously, we can’t test them all, but we think we have a pretty good sample.
Dexterity Tests
Dexterity is defined as the ability to manipulate small objects. Previous tests include the and Bennett Hand-Tool Dexterity Test (BHTDT) and the modified pegboard test. The BHTDT required individuals to disassemble nut, bolt and washer combinations and was the standard test from 1971 until 2000 (2) . However, the test was widely disliked because it was lengthy and failed to properly mimic firefighter demands. So, in 2000, the modified pegboard test, based on work conducted by Dodgen et al., was adopted as the dexterity test for firefighting gloves (4). This test requires individuals to pick-up and place twenty-five knurled pins into a test board.
Grip Tests
Gloved and bare-handed grip strength studies have produced vastly different results – particularly when measuring torque strength (turning) and squeeze strength. These differences are the result of a number of different variables; including the direction of the torque, the orientation of the hand and the diameter of the handles (6-9). These issues are similar to what we found during our grip test study last year (link). Looking specifically at the impact of gloves on grip strength, we know a few factors produce a large effect. A 1986 study by Cochran, et al. showed that even a thin cotton glove can reduce grip strength by as much at 7.3% (10). More recent studies have shown that grip strength decreases found during gloved trials are largely attributable to the additional effort it takes for the wearer to bend, compress and stretch a glove (11).
Another factor also cited as affecting grip strength is the material’s coefficient of friction (“stickiness”). To assess this factor under real-world conditions many studies use both wet and dry test of vertical and horizontal pulling (1).
Overall Comparisons
When it came to dexterity tests, better performing gloves seem to have the following characteristics: less bulk (typically 2-D design), outer shells constructed from synthetic kangaroo or elk (depending on test), and moisture layers of polyurethane (1).In the grip tests three materials have been found to deliver the poorest grip performance: elk, pigskin and cow. An extensive 2011 study equated the material’s poor performance to their inherently higher thickness. The three best performing leathers were: kangaroo, digiroo and goat (1).
On average most research seems to support the idea that decreasing palm shell thickness, and not necessarily total palm thickness is the best way to increase grip performance (1). The same 2011 study mentioned above concluded that “a glove with a goat palm shell material incorporated into either a 2- or 3-layer palm composite would provide the best grip performance” (1).
REFERENCES
(1) Watkins J. Thesis: Evaluation of Grip and Dexterity Test Methods for Characterization and Improvement to Structural Firefighting Glove Design. North Carolina State University, Raleigh, NC. 2011.
(2) Bennett, George K. Bennett Hand Tool Dexterity Test (H-TDT). TalentLens from Pearson Web site. http://www.talentlens.co.uk/select/bennett-hand-tooldexterity-test.aspx. Accessed: 3 MAR 2016.
(3) NFPA 1971 Report on Proposals. MA : NFPA, 1997.
(4) Dodgen, C; Gohlke, D; Stull, J and Williams, M. Investigation of a New Hand Function Test Aimed at Discriminating Multi-layer Glove Dexterity. C.N., Henry, N.W. Nelson. Performance of Protective Clothing: Issues and Priorities for the 21st Century: Seventh Volume. West Conshohocken: American Society for Testing and Materials. 2000
(5) NFPA 1971 Standard on Protective Ensembles for Structural Fire Fighting and Proximity Fire Fighting. 2007.
(6) Kong, Y and Lowe, B. Evaluation of Handle Diameters and Orientations in a Maximum Torque Task. International Journal of Industrial Ergonomics; 35, 2005.
(7) Mital, A; Kuo, T and Faard, H. A Quantitative Evaluation of Gloves Used with Non-Powered Hand Tools in Routine Maintenance Tasks. Ergonomics; 27, 1994.
(8) Riley, M; Cochran, D and Schanbacher, C. Force Capability Differences Due to Gloves. Ergonomics; 28, 1985.
(9) Chen, Y; Cochran, J; Bishu, R and Riley, M. Glove Size and Material Effects on Task Performance. Proceedings of the Human Factors Society 33rd Annual Meeting, 1989. Vol. 1989.
(10) Cochran, D; Albin, T; Bishu, R and Riley, M. An Analysis of Grasp Force Degradation with Commercially Available Gloves. Santa Monica, CA. Proceedings of the Human Factors Society 30th Meeting. 1986.
(11) Wimer, B; McDowell, T; Xu, X; Welcome, D and Warren, C. Effects of gloves on the total grip strength applied to cylindrical handles. International Journal of Industrial Ergonomics; 40. 2010.