Mining Contract: Efficiency Improvement Study of Mine Rescue Breathing Apparatus and Development of an Improved Prototype CCBA
This project will investigate alternative system designs or current system modifications for mine rescue breathing apparatus, to determine the extent of potential efficiency improvements in duration or reduction in size/weight over existing products. Alternative system designs or current system modifications will be investigated to develop a proof of concept demonstrator, produce prototype improved rescue breathing apparatuses, and perform verification testing.
Contract Status & Impact
The current NIOSH certified Self Contained Oxygen Breathing Apparatus (CCBA) currently used for mine rescue is a semi-closed type device that contains an oxygen source (HP cylinder), a constant mass metering system in conjunction with a demand valve for injection of breathing gas and an integral chemical scrubber to remove carbon dioxide. With this type of design, Oxygen is added at a preset rate not less than 1.5 lpm regardless of the user’s actual breathing rate, up to activation of the demand valve. Once the demand valve is activated, gas is added as required by the user. As such, large inefficiencies should only occur at low breathing rates where gas is added to the system at a constant rate (no demand) regardless of breathing rate (ventilation rates well below the 36 lpm that would result in oxygen consumption of less than 1.5 lpm). It is the set gas injection rate at low breathing rates that causes inefficiencies and waste. If that rate could be tied to the users breathing rate throughout all conditions, or electronically controlled, a savings in gas could be realized and the cylinder could be made smaller and less bulky or the duration of the CCBA could be extended.
Scope of Work
This work will be accomplished by an analytical study adapting an existing mathematical model followed by producing a proof of concept CCBA based on the results of the analytical study and then developing a field capable prototype suitable for manned testing. Field capable prototype is defined as a prototype that is able to be tested in a man worn configuration, but not a production grade prototype. Significant design for manufacturability is expected in order to reach a production grade design. A field capable unit is meant for feasibility and exploratory testing in the field to help make program decisions. The field capable unit will not be as robust as a production grade unit would be, and may be prone to breakage in actual use.
Task 1: Adapt an existing mathematical model to model the two current NIOSH approved CCBAs, namely the Draeger BG4 and Biomarine BioPak 240 Revolution and characterize alternative breathing system concepts to include closed circuit and electronically controlled systems. For a given mission duration, the analysis will explore the size required, the risk associated with implementation, and the relative cost of each alternative system. Using size, risk and cost as qualifiers, a recommendation will be made as to which system would be most likely to succeed as a mine rescue CCBA. The detailed sub-tasks under this task are:
1. Modify existing mathematical model for analyzing Mine Rescue CCBAs.
2. Apply math model to mine rescue CCBA units Draeger BG4 and Biomarine BioPak 240. The modeling information will be used to conduct an analysis of required resources (breathing air, oxygen, diluent, chemical scrubber, compliant volumes, etc) of alternate system designs to determine system size.
3. Model alternative systems for optimizing the efficiency of mine rescue CCBA.
4. Determine the required components (piping, regulators, valves, scrubber, electronics, etc) to assign a level of complexity and cost to evaluate the risk to implementation from a reliability, maintainability and manpower perspective.
5. Compile Interim Report A. of work accomplished in task 1 with expected performance, relative costs, relative size of concept systems, other findings and recommendations for task 2.
Task 2: A proof of concept CCBA will be developed based on the recommendations from Task 1. The proof of concept will be robust enough to enable unmanned testing to be conducted in order to validate the mathematical models and demonstrate that the concept is feasible. The detailed sub-tasks under this task are:
1. Design/ configure mechanical components, scrubber, gas supply, etc for high and low pressure pneumatic circuits for the proof of concept demonstrator.
2. Design and/or adapt an electronic control system if deemed necessary from task 1 results.
3. Procure and produce parts for building a demonstrator.
4. Construct demonstrator.
5. Conduct unmanned tests to collect data on duration, resistive effort (breathing resistance), inspired gas temperature, carbon dioxide and oxygen concentrations.
6. Compile Interim Report B of work accomplished in task 2 with unmanned test results, other findings and recommendations for a field capable prototype.
Task 3: Develop the proof of concept CCBA into a field capable prototype unit suitable for manned testing. Conduct unmanned testing to ensure proper function and achievement of performance goals. Conduct manned testing. The detailed sub-tasks under this task are:
1. Design mechanical (and electronic if required) components, scrubber, gas supply, etc. for high & low pressure pneumatic circuits for the field capable prototype. Ergonomic factors for use in low seam coal mines need to be considered in the design.
2. Procure and produce parts for building two prototypes.
3. Construct prototypes.
4. Conduct unmanned tests to collect data on duration, resistive effort (breathing resistance), inspired gas temperature, carbon dioxide and oxygen concentrations.
5. Conduct manned tests on the prototypes according to work rates in tables 2 and 3 in 42 CFR Part 84 Sub-part O. The stressor parameters are in table 1 of this rule.
6. Refine both prototypes with any improvements through experience gained from testing. Refinements are defined as any improvements that can be made without the need to procure additional or alternate parts and are reasonable to make within the scope of this task. Conduct further unmanned tests as necessary.
7. Compile a technical data package on the prototype consisting of drawings, solid model files, specifications, parts lists and other technical information that was used to develop the prototypes.
8. Compile an operating and service manual for the prototype sufficient to allow Division of Mine Science and Technology (DMST) personnel to setup, operate and service the prototype.
9. Compile final report on findings in task 3 with comparisons with the original mine rescue CCBA. Recommendations for developing an improved commercial mine rescue CCBA should also be included in this report.