Comparison of Human Factors Characteristics of the Kirby Morgan(Trademark) 37 and MK 21 Helmets During a Chamber Dive to 380 FSW
Abstract
The human factors characteristics of Kirby Morgan(TradeMark) 37 (KM 37) and U.S. Navy MK 21 diving helmets were compared. Both helmets were derived from the Kirby Morgan KM 17 A/B helmets, except that the KM 37 used a new Tri-Valve(TradeMark) Exhaust System and a neck dam/neck ring assembly, chin support, and neck pad from the Kirby Morgan 21 helmet. The KM 37 and MK 21 helmets both used the same demand regulator. Immersed in 10 ft of water in a hyperbaric chamber pressurized to 370 feet of seawater, eight male U.S. Navy divers performed one dive with each helmet. Breathing gas was a 96% helium, 4% oxygen mix, and water temperature was 35 plus or minus 2 F. Diver dress consisted of a hot water suit, gloves, and hood. For each helmet doffing and donning, divers used a six-point category scale to rate their comfort, vision, ability to communicate, and past accessibility and operability. A 12-point category ratio scale was used to obtain subjective ratings of respiratory effort for each helmet. Divers were not kept blind from the helmet they dived. Calculation of inferential statistics was inappropriate, due to the small number of divers relative to the large number of the characteristics rated and the narrow range of categorical ratings within each characteristic. Overall diver ratings of helmet characteristics tended to favor the KM 37 over the MK 21. On the average, the KM 37 was rated slightly better for doffing and donning, for diving vision and comfort, for parts accessibility and operability, and for requiring less respiratory effort thin the MK 21. However, the MK 21's noise levels and communications were rated slightly better than those of the KM 37. No statistically significant difference was observed between the specific form, fit, and function characteristics of the helmets.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2005
- Accession Number
- ADA442841
Entities
People
- N. A. Carlson
Organizations
- United States Navy Experimental Diving Unit