Is the BioPak 240R a positive-pressure, pressure-demand device?

The BioPak 240R is a positive-pressure, pressure-demand, constant-demand device. What do these terms imply?

Positive-Pressure: The BioPak 240R has been certified to provide positive breathing pressure to the user for EN145 breathing rates of 30, 50, 75 and 100 liters per minute; and, NIOSH breathing rates of 40 liters per minute. Positive pressure refers to the pressure within the breathing loop of the BioPak being higher than the atmospheric pressure outside of the breathing loop.

Pressure-Demand: Pressure demand implies that the BioPak will deliver additional oxygen into the breathing rate based upon internal pressure of the BioPak breathing loop. A better nomenclature for this term would be “volume-demand”. The BioPak will always keep a positive pressure in the breathing loop and does not actually measure the internal pressure during operation. Demand adds are provided by the BioPak when the user consumes more oxygen than what is being supplied by the constant add. This results in a lower volume in the breathing chamber that is compensated for by the diaphragm. When the volume decreases enough, the diaphragm will actuate the demand add valve to add oxygen into the breathing loop. This system is therefore totally self-regulating to the exact needs of the user.

Constant-Demand: The BioPak will deliver a stream of oxygen into the breathing loop throughout the duration of use. This flow of oxygen is intended to furnish enough oxygen to support a user at a moderate work rate such as strenuous walking. The flow is controlled by a flow restrictor within the delivery system and is not altered based upon the needs of the user. If the user oxygen consumption exceeds the rate of the constant add then the demand add will be activated. If the user oxygen consumption is lower than the constant add then resultant excess volume is vented out of the breathing loop.

What is “Solid-Core” CO2 scrubber technology?

“Solid-Core” scrubber technology refers to the design of the CO2 absorbent itself. With Solid-Core technology there is no need for the user to measure or fill a scrubber canister with granular absorbent. A Solid-Core scrubber will not use any container that requires user filling and will also offer the further advantages of non-dusting, non-settling and non-channeling over granular absorbents. Solid-Core absorbents are supplied to the user in cases of four single use packages to eliminate errors in BioPak scrubber installation. The BioPak is the ONLY respirator available with Solid-Core scrubber technology.

What is Tidal Volume and why is this important?

Tidal volume is defined as the volume of gas that can be stored within the breathing loop for user consumption at any one time. The larger the tidal volume the greater the benefit to the user for several reasons. A large tidal volume will provide more breathable air than the user can inhale in one breath thus reducing situations of low inhalation pressure or a feeling of “oxygen starvation” as well as reducing demand oxygen additions resulting in oxygen conservation. Additionally, a large tidal volume will also be able to accept a larger exhalation gas volume from the user thus limiting the number of vent situations from the breathing loop and conserving breathable air. Thus a large tidal volume will provide benefits of improved breathing resistance and oxygen conservation to the user.

What are the materials of the exposed components of the BioPak?

All external components of the BioPak are constructed from flame-rated materials. Additionally, the external housing components of the BioPak are constructed from materials that are static dissipative to avoid the generation of static sparks that may lead to fire in hazardous atmospheres.

When was the design and certification of the BioPak 240R completed?

The design of the BioPak 240R was conducted based upon desired features of operation determined from an extensive user survey conducted in March of 2004. Actual design effort and in-house testing was completed by Biomarine in March of 2006. Certifications were granted as follows: EN136/145: March 2007, MA (China): February of 2007, and NIOSH/MSHA: June of 2007, DGMS (India): September 2010.

What are the differences between the standard and fire-rated harnesses of the BioPak 240R?

The standard harness is constructed of nylon webbing, nylon straps and Acetal buckles; and, the standard harness will not stand up to direct open flames or high radiant heat due to the properties of the materials of construction. The fire-rated harness is constructed of Nomex ® and Kevlar ® webbing and straps with metal buckles and will withstand exposure to direct open flames and high radiant heat. The fire-rated harness also provides additional features of color-coded strap identification, increased adjustment features and better comfort as compared to the standard harness. Finally, due to the materials of construction, the fire-rated harness will also be of superior strength as compared to the standard harness.

Where is the breathing bag located in the BioPak?

The BioPak is designed with no breathing bag. Instead the BioPak is designed with a breathing chamber that contains a flexible diaphragm. This design provides a distinct advantage over a breathing bag design as it will provide shielding against penetration of the soft rubber diaphragm even with the upper housing not installed. A breathing bag design will be totally exposed to penetration hazards should the housing of the respirator become dislodged or breached.

Does the BioPak have an exposed breathing bag?

No. The BioPak utilizes a flexible diaphragm housed within an injection-molded housing to provide a robust breathing chamber that is resistant to externally induced damage and punctures. Other breathing respirators employ the use of a breathing bag that is suspended within the housing of the respirator itself. Should the respirator housing become dislodged the breathing bag will be totally exposed to externally generated dangers and hazards.


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:





  • 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 95oF (35oC) for the entire 4-hour duration of man testing under specific conditions. EN145 has certified the BioPak to maintain breathing temperatures under 45oC (113oF) for the entire 4-hour duration of machine testing under specific conditions.

What is the oxygen concentration of inhaled air?

Upon start up the inhalation oxygen concentration will be in the 30-40% range. This level will rapidly rise to over 90% in the inhalation gas as the BioPak fills and nitrogen from the initial ambient air is purged from the system.

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.

Can the BioPak be worn within a Level A suit?

It is physically possible to wear a BioPak under a Level A suit but the user is cautioned that the BioPak will enrich the internal suit atmosphere with oxygen. This is due to imperfect facepiece seals around the user face and periodic BioPak venting into the suit. This problem will exist for any close-circuit respirator as it is impossible to provide a perfect seal on the user face, and any excess oxygen volume in breathing loop is vented from the respirator into the suit. Biomarine has run tests where the BioPak venting gas was fully captured and routed out of the suit; however, the internal suit oxygen levels would still become enriched due to faceseal leaks. A typical level A suit will see internal suit oxygen levels rise to approximately 40% in under one-hour of BioPak use. The issue of enriched oxygen levels is only of concern to a user should the user also locate electronic equipment within the suit that is not rated as intrinsically safe for enriched oxygen atmospheres in proximity to a fuel source.

In what applications can the BioPak be utilized?

The BioPak is suitable for applications where there is a potential IDLH (Immediately Dangerous to Health and Life) exposure for long periods of time such as decontamination, urban search and rescue, rail car accidents, tunnel extrication, mine rescue or confined space entry. It should be noted that the BioPak is not approved for direct exposure to chemical agents (such as Sarin, Mustard or Nerve agents) or biological agents (such as viruses, bacteria or germs).

Can the BioPak be utilized for diving applications?

The BioPak is not intended for diving applications (although the BioPak can be utilized under water in emergency situations) and several aspects of the BioPak design will not make the BioPak a viable diving rig as follows:


  • The use of an oxygen enriched respirator in environments of greater than 1-atmosphere pressure will result in oxygen toxicity that could lead to user death.
  • The BioPak is not designed to be neutrally buoyant and is actually positively buoyant. Therefore it would very difficult to keep the BioPak submerged without constantly floating on the surface of the water.
  • The facepiece utilized with the BioPak is of a curved lens design that will provide a distorted view underwater.

Can the BioPak be used for 1 or 2 hours then taken off the user and reused at a later time without changing the CO2 scrubbers?

To provide absolute safety the BioPak should always be subjected to the full turn around maintenance procedures as stated in Benchman Manual. In the event of an emergency where it is absolutely necessary to use-store-reuse the BioPak without conducting the full turn around maintenance procedure, it is permissible only under the conditions stated below:


  • The oxygen cylinder is closed and the storage plug has been installed into the facepiece adapter.
  • The BioPak is totally sealed with the breathing chamber lid fully closed and the breathing chamber lid can not have been opened after use.
  • That the BioPak is reused within a period not exceeding 24-hours by the SAME user.
  • That the oxygen cylinder has not been refilled or topped off to provide additional oxygen.

These restrictions are put in place to prevent loss of oxygen stores, conserve carbon dioxide scrubber capacity, prevent the internal growth of mold and bacteria and to prevent the transmission of any user-borne viruses or germs.

Is oxygen a flammable gas?

Oxygen is classified as a strongly energetic oxidizing gas and by itself is not flammable. A flammable gas is one that will act as a fuel that will burn in the presence of oxygen. Thus oxygen is not a flammable gas but is an oxidizer. In the presence of oxygen concentrations above atmospheric pressure and concentrations, materials that readily burn in atmospheric conditions will burn more vigorously and may spontaneously combust; and, materials that normally do not burn in atmospheric conditions may burn in the presence of oxygen concentrations above atmospheric pressure and concentrations.

What type of oxygen does the BioPak require?

The BioPak requires the use of oxygen as specified in the User and Benchman manuals. Oxygen must be certified as medical or aviation grade. The use of other types of oxygen may result in user sickness and/or death from impurities, BioPak flow restriction from entrained particulates or BioPak corrosion from entrained moisture.

Can welding-grade oxygen be utilized in the BioPak oxygen cylinder?

NO! Only medical or aviation grade oxygen, as specified in the manuals, can be utilized in the BioPak oxygen cylinders. Other grades of oxygen may contain high levels of contaminates, such as acetylene, carbon dioxide, carbon monoxide or nitrous oxides, that may lead to user poisoning. Welding grade oxygen cylinders are actually filled with the same USP (United States Pharmacopoeia) oxygen grade as supplied for aviation or medical grade cylinders. The difference is that welding grade cylinders are not evacuated into a vacuum between fills and thus run the risk of containing contaminates (most notably acetylene) left over from improper use or closing by the previous owner.

What is the difference between aviation grade and medical grade oxygen?

Aviation and medical grade oxygen is actually the same USP (United States Pharmacopoeia) oxygen grade material. The difference between the two grades actually is in the handling of the finished gas cylinder and the processing of the gas going into the cylinder. Aviation grade oxygen undergoes an additional drying process to prevent freezing at high altitudes where this gas is commonly utilized. The moisture content of aviation grade oxygen will be guaranteed and the cost of aviation grade oxygen is usually higher than that of medical grade oxygen. Medical grade oxygen cylinders are filled with the same gas as aviation grade cylinder less the extra moisture processing. Medical grade oxygen is handled and regulated in the same manner as a prescription drug so some users may have difficulty in obtaining this grade of gas.

What is USP Oxygen?

UPS oxygen is oxygen gas that meets minimum content requirements set by the United States Pharmacopoeia of 99.0 mole % oxygen, maximum 300 ppm carbon dioxide and maximum 10 ppm carbon monoxide. There are seven different grades of USP gas of A, B, C, D, E, F and G. Each grade will have specific requirements for concentrations of oxygen (none lower than 99.0 mole %), water, methane, nitrogen, ethylene, acetylene, carbon dioxide (non higher than 300 ppm), carbon monoxide (none higher than 10 ppm), total hydrocarbons (as methane) ethane and other hydrocarbons, nitrous oxide, halocarbons and solvents as well as dew point levels.

When filling oxygen cylinders to 3000 psi (207 bar) on a booster pump the cylinder pressure may drop over time. How can I ensure that a perfect fill to 3000 psig (207 bar) is achieved?

When oxygen cylinders are filled with a booster pump, the oxygen will become heated due to the work of compression. The heated oxygen will expand and provide additional pressure within the oxygen cylinder. As the cylinder cools the oxygen will contract and the cylinder pressure will lower. The amount of heating and expansion will depend upon a number of factors including speed of filling, amount of filling and source oxygen pressure. To get a “perfect” fill, the cylinder should be allowed to fully cool and then topped off again to the proper level.

Why is it important to keep the booster pump cylinder fill adapters, the BioPak regulator and the BioPak regulator cylinder seal free of grease, oils and dirt?

All of these components will be exposed to 100% concentrations of oxygen at high pressure; and, during oxygen filling these components will also be exposed to high velocities of oxygen as well as pulsations. The presence of grease, oils or dirt on these components provides fuel that could support a fire or explosion due to the heat of filling or the impact of grease, oils or dirt onto the surface of these components. In the presence of oxygen concentrations above atmospheric pressure and concentrations, materials that readily burn in atmospheric conditions will burn more vigorously and may spontaneously combust; and, materials that normally do not burn in atmospheric conditions may burn in the presence of oxygen concentrations above atmospheric pressure and concentrations. Thus IT IS EXTREMELY IMPORTANT to always keep booster pumps components, cylinder fill adapters, BioPak regulator components and BioPak cylinder seal washers free of grease, oils and dirt to limit the potential for fire or explosion by limiting the presence of any fuel.

How does one determine if the carbon fiber oxygen cylinder of the BioPak has been damaged to the extent that it should be taken out of service?

Local regulations will dictate what damage would require pulling a cylinder from service. The user should conduct regular visual inspections of the oxygen cylinder during each turn around maintenance cycle to verify that 1. There are no exposed fibers on the exterior wrap of the cylinder, 2. There is no evidence of external epoxy chipping or peeling, and, 3. There is no evidence of impact to the exterior of the cylinder. Questionable cylinders should be submitted to a local qualified inspection agent for full inspection. Reference the BioPak 240R website for some cylinder inspection details.

Why is it important to use the exact type of cylinder seal on the BioPak regulator on the booster pump filling adapters?

The connection of the cylinder to the BioPak regulator is exactly the same size and type as the connection of the cylinder to the booster pump cylinder fill adapters so the exact same size and type of sealing washer is required for both connections. The use of any other cylinder seal type may lead to leaking connections.

Does the BioPak carry CBRN certification?

There are currently no CBRN (chemical, biological, radiological, nuclear) standards in existence that the BioPak could be certified against. The BioPak has been designed with materials known to provide adequate barriers to such agents; however, without actual CBRN testing there are no other methods to provide a reasonable assurance of resistance.

Does the BioPak carry NFPA certification or approvals?

No. At this time NFPA (National Fire Protection Association) does not have a standard for closed-circuit respirators. Fire fighting battalions and companies in both the USA and Europe have selected the BioPak for use in some of their particular emergency missions.

What approvals does the BioPak carry?

The BioPak 240R has numerous approvals as listed on the Worldwide Approvals page of this website.

How do I receive training for the BioPak?

Training for the use and maintenance of the BioPak can be provided either in the Biomarine factory or at the user site. Standard training is split into two separate sessions. User Training provides basic knowledge of the BioPak, a review of features and instructions for use. Benchman Training provides in-depth review of the BioPak and maintenance training.

How can I train my own team on the BioPak?

There are two basic levels of training known as User and Benchman. Certified Benchmen are permitted to train others to become certified Users. Benchmen are not permitted to train others to become certified Benchmen. A third level of training can be provided from authorized Biomarine Instructors known as Certified Instructor Training. A certified Instructor can train others to become certified Users or Benchmen. To become a certified Instructor, one must be trained by an authorized Biomarine representative.

Can I use the BioPak without the coolant canisters?

In order to maintain NIOSH certification of the BioPak the respirator must be utilized with both the PCM and the ice canisters frozen and installed. EN145 certified BioPak 240R respirators can operate with the frozen ice canisters only, the PCM only, or both the frozen ice canisters and the PCM.

What is the purpose of the white triangular-shaped device located in the breathing chamber?

This device, know as the PCM, is an internal heat exchanger designed to provide additional heat absorption from the inhalation gas. The device contains a phase change material that will regenerate once it has cooled.

What is the liquid material inside the plastic ice canister?

The liquid is nothing more than distilled water. Water is the best heat absorption material known on earth that is both low-cost and non-toxic.

Can the coolant shells of the BioPak 240R be filled with ice cubes instead of using the ice canister?

NO. The use of coolants other than what is specified by the manual will violate the certification of the BioPak. The use of ice cubes will also result in reduced cooling capacity as it will be impossible to pack as much ice density into the coolant shell using ice cubes as is possible with the ice canister. The use of ice cubes in the coolant shells will also result in the loss of cold melt water from the coolant shells as the shells are not sealed against such leakage. The loss of melt water will further reduce cooling capacity as compared to the ice canisters. Finally the use of ice cubes in place of the ice canister will result in cold melt water running down the BioPak to be deposited on the back on the user, soaking the pants and legs.

What is Pre-Packing the BioPak?

Pre-Packing the BioPak refers to conducting full turn around maintenance procedures that include installing the filled oxygen cylinder and the carbon dioxide scrubbers. This procedure is explained in the Benchman Manual and will allow the BioPak to be stored in a near ready condition for up to one-year. Pre-Packing of the BioPak is only permitted with the Biomarine Solid Core Scrubber® as described in the BioPak manuals.

What are the mandatory replacement parts of the BioPak?

Unlike other respirator makes and models, the BioPak is designed with no mandatory replacement parts, with the exception of the oxygen cylinder that must be replaced every 15-years due to Government regulations.

How does one know if the proper amount of CO2 absorbent has been installed into the BioPak?

The BioPak is the only respirator that utilizes “Solid-Core” scrubber technology that eliminates the need of the user to measure and fill scrubber canisters. The proper amount of scrubber is provided to the user in single use packaging that will guaranty that the proper amount of absorbent is utilized every time.

The BioPak 240R battery removal ribbon extends outside the battery door after the battery door is installed. Is this permitted?

NO! The battery door contains a gasket to seal the interior of the battery compartment against contact with external ambient air and gasses. The presence of the ribbon underneath the gasket will provide a leak path for external gasses to enter into the battery compartment and will void the intrinsic safety of the monitor device.

Why is the facepiece not included in turn around or long term maintenance procedures?

The facepiece is included in these procedures. The facepiece should be inspected, washed and disinfected after each use as stipulated by the turn around maintenance procedure. The facepiece should be included in the inspection of components under long term maintenance as stipulated by long term maintenance procedures.

How is it determined if the check valves of the facepiece are functioning properly?

The User Manual specifies a check valve and face seal functionality test that is to be performed each time the BioPak is donned. This test will validate check valve function as well as determine that the face seal of the facepiece is properly made on the user.

Can the same disinfectant be utilized on the BioPak as is utilized on other equipment?

The BioPak should be cleaned and disinfected according to the procedures stated in the turn around maintenance procedure using the disinfectant specified by the turn around maintenance procedure or approved by Biomarine. The use of other types of disinfectants could cause damage to the facepiece lens or attack the plastic and rubber components of the BioPak.



Can the BioPak be stored underground and under what conditions?

Storage of the BioPak can occur in any location that will not exceed the storage temperature limits stated in the manual. The storage location shall be in an area that will keep the BioPak isolated as much as possible from contact with water, dirt and sources of damage such as impact, excessive vibration or crushing. It is strongly recommended to store the BioPak in a hardened case to provide further protection.

Do the moisture sponges have to be damp when installed into the BioPak?

The moisture sponges should be BONE DRY if installed into a BioPak that will be stored for a period longer than 24-hours. Storage of the BioPak with damp sponges will promote the growth of bacteria and mold within the breathing chamber. Just prior to use, the user can install damp sponges into the breathing chamber. Starting out with damp sponges will aid in sealing the flow path of breathing gas so it travels around the coolant canisters and thus will produce cooler air. It is not necessary to install damp sponges into the breathing prior to use. Not installing damp sponges just prior to use will only result in slightly elevated breathing temperatures until the sponges become wetted.

Can I use an existing facepiece with the BioPak?

Existing customer facepieces can be utilized on the BioPak providing that they are of the same type and model approved for use with the BioPak and providing that the facepieces are subjected to a quality inspection by a Certified Biomarine agent.

What are the BioPak “end of mission life indicators”?

The BioPak provides the user with three separate types of end of mission life indicators. A mechanical indicator is provided as a red portion of the remote pressure gauge. When the needle of the gauge is within the red band the BioPak is nearing the end of the mission life. A visual indication is provided by a flashing LED lamp that will flash red as soon as the remaining oxygen stores are at 25% of full capacity and will continue flashing until the BioPak cylinder is closed or the oxygen is fully consumed. A horn will sound for a ten-second period when remaining oxygen stores are at 25% of capacity. The horn will then change to a chirp that will increase in frequency until the BioPak cylinder is closed or oxygen is fully consumed. The horn and LED indicators operate independently and isolated from the gauge so that the BioPak is provided with redundant alarming systems.

Are the electronic alarm components in the BioPak safe?

The electronic components of the BioPak are all contained within the monitoring system. This device has been tested and certified for use underground as intrinsically safe under the numerous standards listed on the Worldwide Approvals page of the website.

Is it possible to drink water when using the BioPak?

YES! The BioPak can be supplied with an approved Hydration System that permits drinking of liquids WITHOUT removing the facepiece or breaking into the breathing loop. A 1.5-liter exchangeable reservoir is connected to the harness waist belt and a transfer tube extends to a facepiece interface device. The interface device permits the insertion and withdraw of a bite valve into the user’s mouth during use. The reservoir can be replaced during use without inducing breathing loop leaks. The hydration system can be adapted to any BioPak 240R respirator by the user in the field.

Are there protective options for the rubber breathing hoses?

Yes. The BioPak has several protective devices for the breathing hoses as listed below:


  • Anti-Crush Rings: These are injection-molded rings from a stainless steel/polycarbonate alloy that will slide over the breathing hoses and lodge into position between the hose convolutions. The presence of the rings will prevent hose collapse from pinching and will allow the user to carry equipment or other objects on their shoulders on top of the breathing hose.
  • Kevlar® Hose Covers: These covers are fitted over the hoses and closed with a zipper. The Kevlar® mesh of the covers will provide a measure of protection against hose abrasion.
  • Heat Reflective Cover: This cover is a single cover that covers both hoses and the facepiece adapter. The cover is closed with a zipper and is constructed of fire-resistant and heat reflective materials to provide additional protection from high radiant heat.


Why does the blue light of the BioPak 240R TRIM indicator come on immediately after start up and sometimes during operation?

The blue light of the BioPak 240R TRIM indicator is an indication that the user may not have inserted frozen ice canisters into the BioPak. The blue light will ALWAYS come on during the immediate start up of the BioPak as part of the on-board system diagnostic check. Should the blue light come on again 5-10 minutes after start then the user should verify that frozen ice canisters have been inserted into the BioPak. The blue alarm is a warning and will self-cancel after approximately 5-minutes after activation. Should the blue light come on during operation after the initial 15-20 minutes the cable connecting the breathing chamber to the monitor housing is most likely loose and requires tightening.

If the battery of the BioPak 240R monitor fails, how can I determine how much oxygen remains?

In the case of battery failure causing the TRIM indicator to shut down, the user can determine remaining oxygen simply by viewing the pressure gauge mounted to the shoulder harness of the BioPak. In all cases of battery failure the user is instructed to immediately return to a safe location and doff the BioPak. These instructions are presented to the user in the User Manuals as well as during User Training sessions.

The BioPak 240R manual states that the three foam pads serve two purposes. What are these purposes?

The foam pads provide moisture adsorption and retention within the breathing loop to prevent free water from filling the facepiece during BioPak use. The pads also form a seal on the lower edge of the breathing chamber lid baffles to direct air flow around the coolant shells and thus provide a greater efficiency of breathing gas temperature regulation.

How can it be determined that the BioPak 240R upper housing is properly latched?

A properly latched upper housing will conform to the contours of the lower housing all the way around the top lip of the lower housing and the connecting tabs of the lower housing will be fully engaged into the square holes of the upper housing.

How can I be sure the battery in the electronic monitor will last for 4-hours?

The monitor software will perform a self-diagnostic test of itself every time it is powered up. During this check the software will analyze the remaining battery power and will go into alarm should there not be enough power in the battery to last for a 6-hour mission. This provides the user with a 2-hour cushion for a standard 4-hour mission. Additionally, should battery power drop below acceptable limits during a mission the TRIM indicator will provide an alarm in the form of red-green-blue flashes and the horn will chirp.

Why does the TRIM indicator flash red-green-blue when the BioPak oxygen cylinder is opened?

As soon as the oxygen cylinder of the BioPak is opened the resulting pressure in the pneumatics system will automatically turn on the electronic monitoring system. Every time the electronic monitoring system starts the software will run a self-diagnostic test to verify that all cables are properly connected to the monitor, that the TRIM indicator is functioning properly, that the horn is functioning properly and that there is sufficient battery life for a minimum 6-hour operation. At any time the TRIM indicator does not flash the red-green-blue light sequence and the horn does not provide a short chirp at start up, the user should doff the BioPak and request service on the monitor. Additionally, should the monitor detect any fault, the TRIM indicator will continue with the red-green-blue flashes to signal the user of the fault. The user should not use any BioPak in which the TRIM indicator is indicating a fault.