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1. Will the BioPak always provide a minimum of 4-hour duration?
2. What is the nominal duration of the coolant canisters?
3. What is the average temperature of inhaled air?
4. What is the oxygen concentration of inhaled air?
5. What is the breathing resistance of the BioPak during use?

Will the BioPak always provide a minimum of 4-hour duration?
No. The BioPak is rated for a 4-hour duration based upon specific testing conditions set by NIOSH and EN145. BioPak duration, as with all close-circuit respirators, is based upon a number of factors that can lengthen or shorten the actual service life duration as listed below:

FACTORS THAT CAN SHORTEN SERVICE TIME DURATION:

• High user work loads will result in high oxygen consumption rates. The BioPak supplies a finite amount of oxygen to the user. If the user uses that amount at a high rate then service time will be shortened.
• Poor faceseal of the facepiece will lead to leakage that will result in loss of oxygen at rates higher than user consumption and will lead to shortened duration.
• Poor BioPak maintenance may lead to system leaks that will result in loss of oxygen at rates higher than user consumption and will lead to shortened duration.
• Excessive use of the emergency bypass valve will consume oxygen at very high rates that will result in loss of oxygen at rates higher than user consumption and will lead to shortened duration.
• User physical condition will dictate the rate of oxygen consumption. Users that are not in peak physical condition will most likely consume oxygen at greater rates than users that are in peak physical condition.

What is the nominal duration of the coolant canisters?
The coolant canisters have been certified to maintain breathing temperature limits under specific test conditions for a 4-hour duration by both NIOSH and EN145. The actual duration of the coolant in actual use will depend upon factors such as work load on the user and ambient temperature. The harder a user works the more carbon dioxide the user will produce and hence more heat will be produced by the carbon dioxide scrubbing reaction. Elevated ambient temperatures will also place a higher load on the coolant and thus decrease its effective service time. There is no real answer to this question due to the many factors that can affect user work load and ambient temperature. Thus the BioPak has been designed to permit ease of coolant replacement without having to open the breathing loop or open the housing.

What is the average temperature of inhaled air?
This is a difficult question to answer due to the many factors that affect breathing gas temperature. NIOSH has certified the BioPak to maintain breathing temperatures under 95^oF (35^oC) for the entire 4-hour duration of man testing under specific conditions. EN145 has certified the BioPak to maintain breathing temperatures under 45^oC (113^oF) for the entire 4-hour duration of machine testing under specific conditions.

What is the oxygen concentration of inhaled air?
The oxygen concentration of inhalation gas to the user will immediately be in 30-40% range upon initial use of the BioPak and will gradually rise to 60-90% over the 4-hour duration based upon data obtained during NIOSH man testing. The rate of oxygen concentration rise will depend upon the breathing characteristics of the user. If the user is to breathe in a fashion that result in BioPak demand adds or venting then the oxygen concentration will increase due to breathing loop flushing and oxygen replenishment.

What is the breathing resistance of the BioPak during use?
The BioPak breathing resistance will depend upon the breathing rate of the user. The ability of the user to “feel” the breathing resistance is based upon the span of the breathing resistance. The span of the breathing is the difference between peak inhalation and peak exhalation breathing pressures. The larger this difference the more noticeable the breathing resistance will be. Breathing resistance span will increase with increased breathing rates so breathing resistance will become more noticeable at higher breathing rates. The BioPak will typically provide a span of 1” water column at a breathing rate of 40 liters per minute with a peak inhalation of 0.5” water column and a peak exhalation of 1.5 “ water column. This represents the best breathing resistance available in the market today.