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Validation of a diving computer for occupational divers in B.C.
1150-20 C1998
(98FS-14)
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Issue: |
To determine an effective method for calculating decompression timings for occupational divers. |
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Agency: |
Canadian Diving Group |
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Representative: |
Geoff Greenwell |
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Funding: |
$25,000 |
Context: Currently, Defense and Civil Institute of Environmental Medicine (DCIEM) decompression tables are used to calculate decompression timings. The tables employ a manual tabular method, which is difficult to use effectively and does not accurately reflect the varied dive profiles practiced by occupational divers. Divers compromise their safety and increase their risk of inadequate decompression by either neglecting to use the tables or employing them incorrectly. WCB diving statistics indicate that decompression illness accounted for 17% of the diving related injuries/fatalities in BC waters between 1975 and 1996.
Objective: To test the new Bonica Arrow diving computer as an operational tool for primary decompression calculations and information for occupational divers in BC.
Design: Dive computers were distributed to selected occupational divers to use during their normal work dives. Divers used the computers only to collect data, not as a primary means of calculating their decompression timings. The diving data collected from the dive computers was to be downloaded and sent to DCIEM for analysis. Dive profiles from 1000 dives was to be collected for analysis. Divers also provided feedback regarding the operational suitability of the computers.
Setting: Varied diver working environments throughout BC.
Subjects: 25 occupational divers.
Main Outcome Measures: Dive profiles downloaded for the computers and anecdotal information provided by the divers.
Results: Divers encountered numerous technical and operational problems with the dive computers, which required manufacturer maintenance and re-issue to divers at least 100 times. Technical difficulties encountered were inaccurate depth reading, premature battery drainage, software memory failure, inaccurate recording of dive profile data and data download problems. The operational issues reported were unreliability (unit failure), no backup memory, lack of replacement batteries, absence of user capability to replace batteries, digital display difficult to read, unit protection issues and flooding.
As a result of the continuing difficulties with the computers, the number of valid dive profiles collected were insufficient to provide a representative sample for analysis and validation purposes. This resulted in the validation study being concluded early.
Conclusion: The current technical and operational problems with the Bonica Arrow dive computer make it unsuitable for occupational divers at this time. The validation of the dive computer in relation to the decompression calculations was unsubstantiated due to the other problems encountered with the computers.