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Mine Rescue Manual - Section I - Initial Mine Rescue Training
Initial Mine Rescue Training
III. Types of SCBA open and closed scba primary and auxillary apparatus approval
IV. History of mine rescue helmet crews the 1940�s recent disasters mine rescue today
V. Mine rescue and the law before part 49 part 49 eligibility mine rescue station and equipment approval labels
VI. Wearing the apparatus Limitation of wearing the apparatus Time, travel, work rate, and breathing rate Weight and size Seeing Speaking Facepiece seal
VII. The Drager BG-174 A Introduction Where you wear it How it works Oxygen cylinder Oxygen control group Pressure reducer Dosage metering oriface Preflush unit Pressure gauge shut off valve Bypass valve Pressure gauges Chest gauge Cylinder gauge
Warning whistle Breathing bag Regenerative cannister Refillable training cannister Factory packed cannister
Diaphram Pressure relief valve Lung demand valve Inhalation and exhalation valves Breathing hoses Facepiece Cover Wearing harness
VIII. The Drager Bg-174 A, RZ testing procedures Exhalation valve test Inhalation valve test Positive pressure leak test Negative pressure leak test Preflush/pressure gauge equalization test Relief valve test Lung demand valve/breathing bag volune test Bypass/constant dosage test Whistle activation test Whistle duration/pressure gauge shutoff test High and medium pressure test
Mine rescue training must begin with the basic knowledge of self contained breathing apparatus(SCBA) and the primary apparatus that you will be required to wear. This manual is to familiarize yourself to the apparatus, don the apparatus correctly, wear the apparatus in smoke or confined space, and to react properlt in case of failure in any part the SCBA.
In October or November of 1907, Draeger apparatus were used by a crew of men during the fighting and sealing of a mine fire at the Minnie Healy Mine of the Boston and Montana Mining and Smeiting Company in Butte, Montana. On December 6, two Draeger apparatus were used to explore ahead of fresh air after an explosion in the Monongah Mine of the Consolidated Coal Company in Monongah, West Virginia. On December 19, apparatus were used after an explosion in the Darr Mine of the Pittsburgh Coal Company in Jacobs Creek, Pennsylvania.
b. Primary and Auxiliary SCBA- In mine rescue work, apparatus are classified as being either "primary" or "auxiliary" apparatus depending on how much air or oxygen they can supply to you when you wear them. Primary apparatus are apparatus that have a minimum of 2 hours service time. Auxiliary apparatus are units which provide, by law, 30 to 60 minutes' service time.
b. The 1940�s- In the 1940's, World War II spurred increasing demand for mined products, so more miners were put to work. At the same time, the mines were becoming more highly mechanized. These factors combined to produce more hazards, and the result was more chance for disaster.
In terms of sheer numbers, the disaster statistics of the 40's came nowhere near matching those of earlier years, but they were nonetheless sobering. In 1940, for example, the Bartley No. 1 coal mine in West Virginia claimed 91 lives. In 1942, 56 died in the Christopher No. 3 coal mine disaster also in West Virginia. And a disaster at the Centralia No. 5 coal mine in Illinois claimed 111 lives in 1947.
c. Recent Disasters- Although these changes have helped reduce the incidence of disaster in the mines, they have not totally eliminated the problem. Disaster still haunts the mining industry. This becomes all too evident as you call to mind some of the disasters that have taken place in recent years.
Witness, for example, the tragedy that took place at the Sunshine Mine in Kellogg, Idaho when 91 miners died from fire and carbon monoxide poisoning in 1972. In 1968, 78 miners died in an explosion al the Farmington No. 9 mine in West Virginia. In that same year, 26 miners died in a disaster inside the Belle Isle Salt Mine in Louisiana. In 1980, an explosion claimed 5 lives at the Ferrel No. 17 coal mine in southern West Virginia. And, in 1981, a methane explosion in the Dutch Creek No. 1 coal mine near Redstone, Colorado killed 15 miners.
d. Mine rescue today- The mine rescue teams today's miners depend on are a far cry from their earlier counterparts. Rescues are no longer disorganized, haphazard affairs taken on by whoever happens to be in the area at the time of the disaster. Today's rescues are highly organized efforts carried out by a group of individuals working together as a team.
Recent developments in mine rescue emphasize two very important areas: training the teams, and improving the equipment they use.
For example, the new Federal requirements for mine rescue, which we'll talk about later on, set minimum standards for setting up, training, and equipping mine rescue teams. The law stresses that each member of the team must have practical training, and it sets guidelines for equipment maintenance and inspection. This helps to ensure that well-trained, properly equipped teams will be ready to work quickly and efficiently during an actual emergency.
Today's teams also have modern technology to thank for the increasingly sophisticated array of equipment they use to supplement their efforts. Early apparatus crews could count on their scabs to provide only one or two hours of breathing protection. Today's teams have much longer duration apparatus, plus many other devices that their predecessors, armed primarily with shovels, picks, and hatchets, probably never even dreamed of.
Today�s team, for example, use modern gas detection and communication equipment. They also have at their command the latest technique and devices for sealing mines and fighting fires.
The computer age has also provided mine rescue with seismic locators, geophones, and other devices used to pinpoint trapped miners. These are all a part of MSHA's
Mine Emergency Operations (MEO), along with two National Mine Rescue Teams - one for coal mines and one for metal/nonmetal mines.
MSHA MEO also possesses the opability to drill boreholes down from the surface to reach miners who, in an earlier time would have been given up for dead. Once a borehole is drilled with what's known as a "survival drill," rescuers can lower cameras, lights, and microphones into the mine to help locate the miners, determine their situation, and lend support and assistance while an escape route is drilled. Once that is complete, the trapped miners can be safely hauled to the surface in specially designed "escape capsules." Rescue teams in some areas (such as Pennsylvania and Utah) also have access to another advanced form of supplementary mine rescue equipment-the mobile mine rescue van. Designed for use during prolonged rescue efforts, these vans are equipped to serve as a base of operations for one or more teams throughout a rescue. The vans are outfitted with standard mine rescue gear such as breathing aphanites, recharging facilities, hand tools, and first aid supplies.
Some of the vehicle can boast the additional distinction of being virtual "moving laboratories," equipped with computers and other devices sophisticated enough to perform delicate tests like on-site gas analysis-a time consuming task previously performed only in distant laboratories.
V. Mine rescue and the law
a. Before Part 49- Until recently, 311 underground mines were not required to have access to mine rescue teams. Many of the teams now in existence were set up voluntarily -often in reaction to the tragedy of a major disaster. Other mines often followed suit, realizing that even though they had not experienced a disaster, it paid to be ready for one.
Many state departments of mines set up teams of their own so that they too would be ready to lend a hand if a disaster should occur. MSHA also trained and outfitted its own teams to ensure they would be ready to respond at a moment's notice to a disaster anywhere in the United States.
b. Part 49- It wasn't until recently, however, that the U.S. Congress passed laws making it mandatory for every mine in the country to have access to mine rescue teams. These regulations are contained in Part 49 of Title 30 of the Code of Federal Regulations (30) "Part 49", as we�ll refer to it here, will have far-reaching consequences for mine rescue. For one thing, by making it mandatory for every mine to have rescue teams available, it will greatly increase the number of teams throughout the country.
Part 49 also specifies how many members each team should have, what equipment they should have on hand, and how the equipment is to be stored and maintained. The law also contains requirements for the notification plan to be used during an emergency. Part 49 also specifies what physical standards and other qualifications you must meet to be eligible for team membership, and it sets some minimum standards for the amount and type of training you receive. According to law, if you're a new mine rescue team member, you must have least 20 hours of instruction on how to use, care for, and maintain the breathing apparatus.
Once you've completed this initial training, the law requires that you have at least 40 hours of additional training, every year as long as you're on the team. This is known as "advanced refresher training. As part of this advanced refresher training, the law requires that you have at least one underground session every six months. The law also specifies that you practice under oxygen for at least two hours every two months during your refresher training.
Besides "reviewing" your basic apparatus skills, your 40-hour advanced/refresher course will introduce you to advanced mine rescue skills, keep you abreast of changes, and give you a chance to do some practical, problem-solving work.
c. Eligibility- As we mentioned earlier, Part 49 also designates what standards make you eligible for team membership. For instance, the law says that in order to be on a team you must have worked in an underground mine for at least one year during the past years. You also qualify if you're employed on the surface but regularly work underground.
The law also specifies what physical standards you must meet in order to become a team member. d. Mine Rescue Station and Equipment- Another part of the law requires that a mine rescue station be established "to provide a centralized storage location for mine rescue equipment." The rescue station is where you'll store and maintain equipment so it will be ready to use immediately during an emergency.
The law also specifies what equipment must be available at the mine rescue station. For instance, according to law, the station must be outfitted with at least twelve self- contained breathing apparatus, equipment necessary to test them, and enough carbon dioxide absorbent chemicals and oxygen to supply six hours of breathing protection for each team member.
The law also requires that the rescue station be provided with at least twelve permissible cap lamps, facilities to recharge them, two gas detectors for each type of gas found in the mine, and two oxygen indicators or flame safety lamps. According to law, there must also be an approved mine rescue communications system at the rescue station, and you must be provided with enough spare parts and other tools to maintain both the communications system and the breathing apparatus. The law also tells how your apparatus and other equipment should be maintained. It specifies how often equipment should be checked, by whom, and how Iong records of these tests must be kept on file. With reference to this, the law says:
"Mine rescue apparatus and equipment shall be maintained in a manner which will assure readiness for immediate use. A person trained in the use and care of breathing apparatus shall inspect and test the apparatus at intervals not exceeding 30 days. A record of inspections and tests shall be maintnined at the mine rescue station for a period of one year."
To receive NIOSH and MSHA approval, selfcontained breathing apparatus must meet specific requirements as to design and construction, and must operate satisfactorily during a specified series of actual wearing tests. The exact requirements for approval are outlined in Title 30, of the Code of Federal Regulations (30CFR), Part 1 ].
Certain apparatus approved formerly under Schedule 13 by the Bureau of Mines have been "conditionally approved" under 30 CFR and can still be used if manufactured and purchased before June 30, 1975, and if the apparatus has been properly maintained.
The McCaa apparatus is an example of an apparatus approved under Schedule 13 and still acceptable for mine rescue work.
e. Approval Labels- AlI approved apparatus are required by law to display an approval label on the unit. This label must bear the MSHA label and the sea1 of NIOSH, an approval number, and the name of the apparatus's manufacturer.
In addition to this, the label tells:
l. The type of apparatus (compressed oxygen, liquid oxygen, and so forth);
2. The approved service time of the apparatus (for instance, 2 or 3 hours);
3. The part numbers for component parts approved to be used with the apparatus (such as the facepiece part number or the breathing bag part number);
4. The limitations of the apparatus (such as the temperature range for use of the apparatus); and
5. Any special precautions that should be taken while using the apparatus. An apparatus approved under Schedule 13 will not have a current NIOSHl/MSHA approval label on it. However, the apparatus should carry a Bureau of Mines approval label, bearing the seal of the Bureau and listing information similar to that on the current NIOSH/MSHA approval labels.
All approvai labels should be read carefully so that the apparatus can be used in an approved manner. Also, if you should ever be in a situation where you are using an apparatus which is new to you (perhaps another team's equipment), the label will give you some basic information to help familiarize you with the apparatus.
VI. Wearing the apparatus
When you enter a mine as a mine rescue team, you may find yourself in smoke or poisonous gases, or not enoueh oxygen to keep you alive. That is why you wear an apparatus in mine rescue work. The apparatus will prorect your lungs from smoke and poisonous gases, and provide safe air for you to breathe. There are, however, some conditions under which the apparatus will not entirely protect you:
1. Self-contained breathing apparatus will not protect you from toxic amounts of poisonous gases, dusts, or vapors that may injure your skin or be absorbed through your skin into your system. For example, fairly high concentrations of ammonia will injure your skin and hydrogen cyanide can be absorbed through your skin.
2. Your apparatus will not protect you if it is worn extensively in petroleum vapors. These vapors will permeate and deteriorate the rubber parts of the apparatus.
3. In air which is much above normal atmospheric pressure(14.7 pounds per square inch), it can be dangerous to wear an apparatus that supplies you with pure or nearly pure oxygen. Special precautions and procedures from the apparatus's manufacturer which allow the safe use of breathing apparatus under high atmospheric pressure should be followed.
a. Limitations of Wearing an Apparatus- Wearing any apparatus has its limitations. That is, there are things it cannot do and special factors you should take into consideration whcn you wear it.
In general, seeing, speaking, moving, working, and breathing are all a little different when you are wearing the apparatus. Understanding these differences and learning to cope with them can have a significant arfect on how well you do your job.
Apparatus designed by various manufacturers are all going to be a bit different. You will be practicing wearing and working with your apparatus so that you can get used to the feel of it and how it works.
For now, we will talk generally about what it's like to wear an apparatus and what the general limitations are.
b. Time Limit, Work Rate, and Breathing Rate- Any self-contained breathing apparatus that you use will limit the time you'll have in which to work underground. Your apparatus wiil be approved for a specified amount of time per wearing called the "service time."
The service time is established assuming that you work at a moderate rate. If you work extremely hard, you will be breathing faster and you will be consuming your oxygen or air at a faster rate. Also, nervousness or excitement can cause you to breath faster; and use more oxygen. In addition, the roughness of the terain you must travel and the heat and humidity of the area you will be in can affect your breathing rate and consequently, the service time. You should try to avoid breathing too quickly while wearing the apparatus. Short, shallow breathing or panting causes you to get an insufficient amount of oxygen and you may begin to feel faint. So if you find yourself breathing quickly, try to control your breathing and slow it down.
Also, you will probably experience some resistance to breathing while wearing the apparatus' facepiece. This is is caused by the air pressure in the facepiece. With practice and familiarity with the apparatus, you should be able to compensate for this resistance.
c. Weight and Size of Apparatus- The requirements for apparatus approval specify that an apparatus can weigh up to 40 pounds. This extra weight you will be wearying will affect your endurance, your rate of work, and your maneuverability. Therefore you will have to practice working with the apparatus on so that you can get used to moving and working with the extra weight and bulk.
One thing to remember while wearing the apparatus:All vour movements should be slow and deliberate.
d. Seeing- The requirements for apparatus approval specify that facepieces be designed and constructed to provide adequate vision. Still, when you wear the facepiece, you will find yourself turning your head and body more often than usual to see things around you.
Remember again: All movements while wearing the apparatus should be slow and deliberate.
Also, the heat and moisture produced within some of the apparatus can cause the facepiece to fog, making it difficult for you to see. Yet there are special "anti-fog" solutions that can be applied to the facepiece lens to help prevent it from fogging up on you.
e. Speaking- It is going to be more difficult to communicate while wearing the facepiece because your voice will be distorted. All the facepieces have a speaking diaphragm to transmit your voice to the outside of the facepiece but they tend to muffle your voice. You may find yourself having to speak a little louder and slower than usual in order to be understood. Also, you should try to talk as little as possible while wearing the apparatus. This means to cut our all unnecessary "chatter" so that only important information is communicated.
f. Facepiece Seal- When you wear the facepiece, it is extremely important to have a good tight seal around your face. This is known as the face-to-facepiece seal, or simply as the facepiece seal.
A good seal will prevent smoke and poisonous gases from leaking into the facepiece and infiltrating your air supply. It will also prevent any inadvertent leak of oxygen or air from inside the facepiece to the outside atmosphere.
So it is very importanr to tighten your facepiece snugly to your face and test it to make sure there aren't any leaks. Such things as very prominent cheekbones or deep scars could prevent a good seal. Other conditions that prevent a good facepiece seal are: (1) eyeglasses, and (2) beards and bushy sideburns, which are not recommended to be worn with any breathing apparatus.
Eyeglasses can prevent a good face-to-facepiece seal and should not be worn with many types of facepieces. Sometimes, however, eyeglasses will fit within the facepiece without disturbing the facepiece seal. Some facepieces even allow for the insertion of corrective lenses directly into the facepiece.
Also, wearing contact lenses with the facepiece on is considered very hazardous even though they don't prevent a good facepiece seal. There is evidence that contact lenses may become lodged above the eye due to pressure in the facepiece, so they should not be worn. VII. The Drager BG-174 A
a. Introduction- The Draeger BG 174-A (or 1 74) is a self-contained,closed-circuit breathing apparatus that you carry on back. For a limited time, it supplies you with oxygen and removes carbon dioxide from the air you breathe.
The Draeger breathing apparatus recycles and replenishes the air in a continuous cycle within the apparatus, completely independent of the air around it.
The BG 174-A weighs about 30 pounds, and its working are protected by a carrying frame and metal cover. If you encounter conditions such as low roof or an obstructed pathway during rescue and recovery operations, you can remove the Draeger BG 174-A from your back and push it ahead of you or pull it behind you.
The Draeger apparatus is also equipped with automatic and manually-operated safety devices and other features, including pressure gauges to let you know how much oxygen you have.
Once the oxygen cylinder is opened, the unit functions by itself, so aside from checking the pressure gauge now and then, you can concentrate on your work.
b. Where You Wear it- The fact that the Draeger apparatus is independent of surrounding air makes it particularly well-suited for mine rescue and recovery work after fires and explosions, where you may encounter smoke, toxic or poisonous gases, fumes, or other conditions that make the air around you unfit to breathe.
The apparatus will not offer protection against poisonous gases absorbed through your skin such as hydrocyanic acid.
Because the BG 174-A can provide you with up to 4 hours of breathing protection. The apparatus is especially good for underground work or in other situations where it may be hard to determine exactly how much time you will need in order to complete your work.
c. How it Works- Basically, the BG 174-A breathing apparatus works like this: When you inhale, oxygen from the oxygen bottle flows through the breathing bag ,and travels up the inhalation tube to you. When you breathe out; the exhaled air passes into a regenerative canister where chemicals remove carbon dioxide, a by-product of the breathing process. Then it's passed along to the breathing bag in the middle of the unit where it's mixed with free oxygen and the whole process begins again. The oxygen you use up when you breathe is replaced from an oxygen cylinder at the rate of I.5 liters per minute. This is known as "constant flow" metering. If you use up oxygen at a faster rate, a lung demand valve built into the apparatus responds by letting more oxygen into the system.
d. Oxygen Cylinder- Once the cover is removed, you can easily see the unit's oxygen cylinder, which is fitted horizontally to the bottom of the frame.
The BG 174-A's cylinder is made or strong alloyed steel. It has a capacity of 2 liters, which is roughly equivalent to 2 quarts. At full pressure the cylinder can contain up to 440 liters of compressed oxygen.
The cylinder must be tested every 5 years to see that it remains in good condition. Just opposite the connection that joins the cylinder to the unit is the cylinder valve which is used to open and close the cylinder. This valve has a special "slip clutch" design which helps keep you from opening or closing it accidentally. To open the cylinder valve, pull out on it and with two fingers, gently turn it counterclockwise until it's all the way open, then turn it back about a half turn. Turning it back half a turn leaves some "play" in the valve so that when you're wearing the apparatus you can reach back and assure yourself that the valve is open.
When you close the valve, again pull it out and with two fingers only. Turn it clockwise until the valve is closed.
The "two-finger" method is recommended because twisting the valve too hard can strip or otherwise damage the threads on the valve seat's spindle.
On the top of your oxygen cylinder is a safety device known as the pressure burst cap.
When the pressure within the cylinder reaches 4450 PSI, the cap will "burst," allowing oxygen to escape through holes in it. This keeps the bottle from rupturing with great force. Heat can cause the cylinder to approach the 4450 PSI "danger limit."
At 2000 PSI, it takes approximately 700' F to make the oxygen within the cylinder expand to 4450 PSI. causing the cap to burst. With a full, four-hour cylinder - 3135 PSI-it takes approximately 300o F to do the same thing .
e. Oxygen Control Group- On the right side of the unit's carrying frame are a number of parts which together make up the oxygen control group. These are the parts that control (or regulate) the oxygen supply as it comes from the cylinder.
The oxygen control group is connected to the oxygen cylinder by a threaded, finger-tight connection, and to the breathing system by way of the preflush/dosage line.
Parts included in the oxygen control group are: the pressure reducer, the dosage metering orifice, the preflush unit, the pressure gauge shutoff valve, and the bypass valve.
f. Pressure Reducer- The pressure reducer is located in the center of the oxygen control group.
The adjustment nut for the pressure reducer is located inside the sealed blue knob-like housing you'll see in the oxygen control group. As its name indicates, this part reduces the pressure of oxygen coming from your cylinder to a more manageable 57 PSI.
g. Dosage Metering Orifice- This oxygen then flows through the dosage metering orifice, a drilled orifice (hole) which meters it to deliver a "constant flow" of about 1.4 to 1.7 liters per minute to the breathing bag. This enough oxygen to sustain you while you're working at a moderate rate. By contrast, while you're sitting in this room, you use up, about eight-tenths (.8) liters per minute.
h. Preflush Unit- Within the housing with a black rubber cover are parts designed to flush the breathing bag with 6 to 7 liters of pure oxygen immediately after the cylinder is opened. The parts within this housing are known as the preflushing unit.
Automatically prefushing the breathing bag serves two purposes: It gets rid of any residual air that might have accumulated in the bag, and it makes the apparatus immediately ready for use in an emergency.
i. Pressure Gauge Shutoff Valve- The parts of the oxygen control group that we'll be talking about next-the pressure gauge shutoff valve and the manual bypass valve-are very important ones. Hopefully, you'll never have to use them. These are "back up" safety devices designed to be used in an emergency. The pressure gauge shutoff valve is the metal lever located between the pressure reducer and the preflush unit. You should close this valve only if you suspect your pressure gauge or pressure gauge line is leaking. (This is usually indicated by a sharp, quick drop in your chest gauge reading or the premature sounding of the warning whistle.)
To activate the pressure gauge shutoff valve, lift the lever approximately 30 to 45 degrees from the horizontal to the stopping point. Lifting the lever shuts off oxygen from your pressure gauge line and warning whistle. It does not affect the constant dosage or the medium-pressure oxygen going to your lung demand valve. Once you've lifted the lever, keep an eye on your chest gauge so you can tell if there's a leak in the gauge or gauge line. If there is a leak, oxygen trapped in the line will escape, making the pressure gauge reading fall quickly. And when the pressure reaches 20 to 25 percent of full cylinder pressure, your warning whistle will sound for 20 to 60 seconds.
These two factors-complete loss of gauge line pressure and the brief sounding of the warning whistle-prove that there is a leak, the pressure gauge line is severed, or the gauge is malfunctioning, so leave the shutoff lever in the "up" position.
However, if your pressure gauge reading does not drop and gas trapped in the line keeps the gauge "frozen" at the pressure you read when you first lifted the shutoff lever, you'll know there is no leak in the pressure gauge line. If that's the case, be sure and put the shutoff lever back down in its original position.
(1) If you don't push the lever back down, your chest gauge will continue to indicate how much pressure you had when you lifted the shutoff lever rather than what's actually in the cylinder.
(2) If your pressure gauge shutoff lever is in the "up" position your warning whistle is isolated. so it cannot sound to let you know when your oxygen is low.
j. Bypass Valve- The second of the two safety features located within the oxygen control group is a black recessed button surrounded by a red rim-the manual bypass.
Like the pressure gauge shutoff valve, the manual bypass is for emergency use only.
It is called a "bypass" valve because pushing it sends oxygen directly from the cylinder to you, hence "bypassing" the parts of the apparatus that limit or control its pressure. Use this bypass valve only if your oxygen control malfunctions and you're not getting the required 1.5 liters of oxygen per minute. To activate the bypass valve, you need only press it for an instant and then release it. The valve is self-closing.
Because it bypasses elements within the system that control oxygen supply, this valve can deliver up to 50 liters of oxygen per minute to the breathing bag. That's far more than you need so use it sparingly.
You should also keep in mind that since the oxygen is coming directly to you from the cylinder, you�ll use up what's in your cylinder much faster. That means you'll have far less time under oxygen. Never use the bypass valve to "freshen" or "cool" the oxygen in the breathing bag. That's simply a waste of oxygen.
Remember to use the manual bypass only when it is absolutely necessary-and when you do, use it sparingly.
k. Pressure Gauges- A pressure gauge is an instrument which measures the amount/pressure of oxygen in your cylinder. The BG 174-A has two of them-a chest gauge and a cylinder gauge. They are marked in increments of 200 PSI and are luminous so you can see them in the dark, or in other conditions that limit visibility.
These two gauges, though they both give the oxygen pressure reading, work independently of each other.
1. Chest Gauge- The chest pressure gauge operates only when the oxygen valve is open. It measures the oxygen pressure going into the apparatus from the cylinder. This gauge is located at the end of the high-pressure line extending from the oxygen control assembly and warning whistle.
The chest gauge is the one you'll refer to when you're actually wearing your Draeger apparatus. It is fastened to the right side of the harness by a rubber strap so it's always within easy reach. When not in use, the chest gauge is protected by a metal cover.
After checking the pressure, the gauge should always be put back into its cover. This holds the gauge and protects it from external damage.
Leading from the unit to the chest gauge is a rubber coated pressure gauge line. Inside the tube's rubber coating is a closely wound spiral high-tension line which is relieved of tension by a bronze core. Remember that if this tube develops a leak, you can lift the pressure gauge shutoff lever to keep oxygen from flowing into it.
2. Cylinder Gauge- The cylinder pressure gauge is attached to the top of the oxygen cylinder. It gives a constant reading of the pressure, whether the cylinder is in storage or in the apparatus. This is the gauge you'll refer to when you fill your cylinder or add a new one. When the unit is in use, the cylinder gauge is not visible because it is under the unit's cover.
l. Warning Whistle- Connected to the pressure gauge line assembly above the oxygen control group is a whistle called the warning whistle. It is designed to warn you when you have only 20 to 25 percent of the original charged pressure left in your cylinder.
It will also alert you to a leak in the high-pressure line leading to the chest gauge. When the pressure reaches the point where the whistle sounds, the leak can be stopped by lifting the pressure gauge shutoff lever.
When the warning whistle sounds, it blows for about 20 to 60 seconds and uses about 3 liters of oxygen.
When you hear this whistle, you�ll know you have approximately 90 liters of oxygen remaining or about 45 to 60 minutes worth of oxygen.
The whistle will sound at about 700 PSI on a 4-hour apparatus, and at 600 PSI on a 3-hour apparatus.
m. Breathing Bag- The breathing bag is located at the center of the unit, protected on all sides by the carrying frame. It is made of a synthetic 3-ply rubber fabric and has a volume of 5 to 7 liters.
The breathing bag has two "sockets" on it. One of these is a threaded socket which connects to the lung demand assembly, and the other elbow socket connects to the regenerative canister. By unscrewing these sockets and the preflush/dosage line, you can remove the breathing bag for cleaning and disinfecting.
n. Regenerative Canister- The metal unit at the top of the apparatus is called the regenerative canister. The special chemicals inside the regenerative canister absorb the carbon dioxide from the air that is exhaled by the wearer. The oxygen in the exhaled air is not affected by the chemicals. It passes through the canister and goes back into the breathing bag where it can be breathed again.
There are two types of canisters you can use with the Draeger apparatus:
1. Refillable training canister.
2. Factory-packed, disposable canister (sometimes referred to as an alkali canister).
The basic difference between the two is that the factory- packed, disposable canister is the only one approved for actual rescue work.
Both canisters have arrows on them The match up to the arrows on the canister holder at the top of the apparatus.
1. Refillable Training Canister- The refillable training canister is approved for training purposes only and has a maximum period of 4 hours use. It is made of stainless steel and can be used over and over again as long as the absorbent chemicals are freshly packed for each use.
Inside the canister is a set of baffles designed to expose more surface area of the chemicals to the exhaled air. The canister must be completely filled each time it is used in order to get good results. You will learn the proper procedure for filling the canister later on in the lecture.
The chemicals used to fill the canister have a shelf life of approximately 2 years from the date of manufacture which is printed on the packaging label. For easy reference, the expiration date for the chemical is also printed on the label.
2. Factory Packed Rescue Canister- The factory packed cannister is similar to the refillable. However, the chemical is higher in concentration to remove virtually all the carbon dioxide from the breathing circuit, and has breathing channels or baffles in which the exhaled air has to travel to be properly cleaned.
It has a expiation date on the label, and string seals or tape seals to insure that the unit has not been used before.
o. Diaphragm- These parts depend for their operation on a very important part of the lung demand assembly-the diaphragm. This is how it works:
This diaphragm moves in or out in response to pressure created by the breathing bag. When the breathing bag has too much oxygen in it, it becomes overinflated and so produces a forward pushing pressure or "positive pressure" against the diaphragm.
On the other hand, when the bag has less than the normal amount of oxygen in it, it becomes deflated, pulling the diaphragm in toward it. This pulling motion is known as "negative pressure."
p. Pressure Relief Valve- The pressure relief valve is the part of the lung demand assembly that keeps oxygen from building up in the breathing bag if you use less than the unit provides. For example, if you're resting, you probably won't consume as much as 1.4 to I.7 liters per minute of oxygen.
The excess oxygen will then fill the breathing bag to the point where it becomes overinflated. The overinflated bag creates positive pressure which pushes against the diaphragm, causing it to move outward against a spring.
As the diaphragm moves outward, it moves away from the sealing bolt, revealing an opening in the diaphragm that normally remains closed. The excess air flows through this opening, escaping to the outside atmosphere thorough a nonreturn valve.
q. Lung Demand Valve- The lung demand valve is the part of the lung demand assembly that automatically lets more oxygen into the circuit if you require more than what's flowing into the breathing bag.
If you are working hard, for example, the amount of oxygen you need may be greater than the 1.4 to 1.7 liters per minute your unit normally supplies. When this happens, the breathing bag deflates with each breath you take until it no longer supplies you with enough oxygen. This is where the lung demand valve comes in.
As the base deflates, negative pressure pulls on the diaphragm. This forces the plunger in the diaphragm to move inward against the valve's stickpin-type lever. The lever in turn opens the valve, allowing oxygen (at 57 PSI) to now directly from the pressure reducer to the lung demand assembly by way of the medium-pressure oxygen line. This oxygen flows into the circuit at a rate of 80 to 120 LPM.
r. Inhalation and Exhalation Valves In a closed-circuit breathing apparatus, keep in mind that it is very important that the breathing air flows only in one direction. If it didn't, you'd risk breathing in exhaled air filled with carbon dioxide, or fresh oxygen might not get to you. In the Draeger apparatus, the inhalation and exhalation valves keep the air flowing in one direction.
During inhalation the air is drawn out of the breathing bag through the lung demand assembly. The air then passes through the inhalation valve near the bottom left side of the lung demand assembly. When the air is exhaled by the wearer, it passes through the exhalation valve located on the top of the lung demand assembly.
Remember, these are one-way valves designed to control the direction of air flow in the breathing system.
s. Breathing Hoses- The breathing hoses used with the Panorama Nova face-piece are made of durable, corrugated rubber. They are very flexible and offer little resistance to inhaled and exhaled air, enabling you to breathe almost as freely as in open air.
The hoses consist of an inhalation hose and an exhalation hose. The inhalation hose has a saliva trap attached to it.
The trap is on the inhalation hose because it must be located on the lowest part of the apparatus when it is worn so that the moisture will settle there. The trap features a chain connection between the trap and its cap, so that the cap cannot be misplaced when it is removed.
The hoses, like the facepiece, have a single coupling assembly (for attachment to the facepiece) with a divider to channel the breathing air. There is also a small dam inside to prevent excess saliva from going into the exhalation hose.
At the other-end of the hoses are two threaded connections for attachment to the apparatus. The inhalation hose (with the saliva trap) connects to the inhalation hose connection at the lower portion of the lung demand assembly.
The exhalation hose connects to the exhalation hose connection near the top of the lung demand assembly.
t. Facepiece- The Panorama Nova is the facepiece used with the BG 174-A. It has a single "panorama" type lens which offers 90 percent peripheral vision, allowing you to see most of what you normally see. It permits unobstructed vision with both eyes, which is very important in judging distances.
The mask has a double-sealing edge for protection against the infiltration of smoke and gases. The Nova facepiece also has a nosecup inside the mask designed to help channel the inhaled and exhaled air to and from the wearer. This nosecup acts as the third sealing edge to protect you from smoke and gases.
The Nova facepiece has a five-stamp head harness, which adjusts to provide a good facepiece seal, and a neck strap which you can put around your neck to support the mask when you are not wearing it. The neck strap can be shortened from its regular length so you can carry the facepiece close to your chest when you are not under oxygen.
It is shortened by attaching the button which is located on the strap, to the small buttonhole on the center head strap.
At the lower part of the facepiece is a single coupling assembly where the breathing hoses are attached. You will notice when you look closely that facepiece connection, that it has divider or ridge built into it. This divider helps to separate the inhaled air from the exhaled air as it passes between the hoses and the wearer.
u. Cover- The cover of the Draeger self-contained breathing apparatus acts as a protective shell for its internal parts. It is made of a lightweight yet rugged metal that will withstand heavy wear and tear.
The cover is specially designed to be slim so that it will fit into tight spots. Sled-like ridges on the cover make it easy to slide the apparatus ahead of you or pull it behind you. Most Drager units in use have covers made of an aluminum alloy. Newer models have covers made of stainless steel.
The aluminum alloy cover has a stripe of high-visibility orange paint and two strips of reflective tape down the center which make it easy to spot the wearer in darkness, fog, smoke, or other conditions that limit visibility. The stainless steel cover has two red reflectors on the lower part of the cover near the fasteners.
On the top right center of the cover is the approval label. It is here that you will and what the approved service time is for the apparatus, the approval number, and the minimum use temperature.
In order to get at the units internal parts, you must first remove the cover. To do this, push in on the step fasteners on the lower part of the cover. When the fasteners release, pull upward and outward on the cover until the tab on top slips out of the slot.
To close it, simply put the top tab into its slot and push the bottom of the cover down over the fasteners until you hear it "snap" into place.
v. Wearing Harness- The wearing harness consists of two adjustable shoulder straps with double slide buckles and a waist belt.
The shoulder straps have plastic rings on the ends that, when pulled down, adjust the straps for proper fit. The double slide buckles are designed for quick release.
The right shoulder strap is equipped with a tension relieve strap. There is a springhook on this strap which clips to the breathing hoses to relieve some of the hoses' weight from your facepiece. VIII. The Drager BG-174 a, RZ testing procedures
a. Exhalation Valve Test- First, zero-adjust the tester by turning the block adjustment knob in the lower left-hand corner of the tester. After this initial adjustment, do not readjust this setting for the rest of the testing.
Remove the cover from the tester's hose connection and screw in the breathing hose adapter, followed by the breathing hoses. This connection should be tight enough to prevent leakage.
To test the exhalation valve: Cap off the exhalation hose and connect the inhalation hose (the one with the saliva trap) to the exhalation valve assembly on the apparatus.
Set the tester in negative pressure pumping and start to work the bellows by pumping with very gentle strokes (you should meet resistance at once). Watch the breathing bag. It should not begin to deflate after 5 seconds, indicating the exhalation valve is working properly: it only allows the wearer's exhaled air to pass into the apparatus-not back out of the apparatus.
b. Inhalation Valve Test- Now to test the inhalation valve: Remove the hose from the exhalation valve, and connect it to the inhalation valve, making sure to position the hose so that the saliva trap is in a vertical position before tightening the connection. This will ensure that the trap is in the proper position when you put on the apparatus.
Switch the selector knob to positive pressure pumping and gently pump. Again watch the breathing bag. It should not begin to inflate after 5 seconds, indicating the inhalation valve is working properly; it only allows the wearer to inhale air from the breathing bag, and not exhale it back into the bag.
c. Positive Pressure Leak Test- Now you are ready to test for air leaking out of the apparatus.
First, sent the relief valve vent (in the lung demand assembly) with the rubber plug provided in the tool kit. Then plug the opening in the warning whistle with the cover, also included in the tool kit.
Now, the tester should already be set on positive pressure pumping, so pump up the breathing bag until the meter needle reads +100 mm H2O (+10 mbar).
Then switch the tester to leak test, and bleed the needle down to +70 mm H2O (+7 mbar).
Start the stopwatch and observe the needle for 60 seconds. The needle should not drop more than 10 mm H20 (1 mbar).
d. Negative Pressure Leak Test- Now, to check for air leaking into the apparatus, including through the relief valve: Remove the rubber plug from the relief valve vent only. Don't remove the whistle cover.
Switch the tester to negative pressure pumping and pump the bellows until the meter reads -100 mm H20 (-10 mbar).
Then switch the tester to leak test and bleed the needle up to -70 mm H20 (-7 mbar).
Start the stopwatch and observe the needle for 60 seconds. After 60 seconds, the needle should not rise more than 10 mm H20 (1 mbar).
e. Preflush /Pressure Gauge Equalization Test- First, remove the cover from the warning whistle.
Then set the tester on negative pressure pumping and open the oxygen cylinder valve by placing two fingers on the knob, pulling it out and rotating it counterclockwise. Open the valve fully, then turn it back one-half turn, the method you should always use when you turn on the apparatus.
The breathing bag should completely inflate due to the preflushing action, and there should sound a short chirp of the warning whistle.
When the preflushing is complete, observe the chest pressure gauge to ensure that it reads within 10 percent of the reading on the oxygen cylinder gauge.
f. Relief Valve Test- You can now check the opening pressure of the relief valve To do this test, open cylinder valve (with tester set on negative pressure pumping and leak test).
The flow of oxygen from constant dosage will cause relief valve to open, with opening pressure indicated on the tester gauge. The valve should open between +10 and +40 H2O(+ 1 and +4 mbar).
g. Lung Demand Valve/Breathing Bag Volume Test- Now that the bag is full, you will be pumping the air out of the bag to figure out: (1) how many liters the bag holds, and (2) how much negative pressure is required before the demand valve kicks in. You can figure out both by pumping the air out of the bag, counting the strokes, and listening.
h. Bypass/Constant Dosage Test- Now that the breathing bag is deflated, you can check to see if the manual bypass valve works to fill the bag in 10 seconds or less. Then you'll be checking to see how much oxygen is metered into the bag when the apparatus is functioning automatically.
Set the tester on the "red" dosage test (0.5 to 2 LPM).
Again put the plug in the vent of the pressure relief valve.
Press and hold the red bypass valve and listen for the flow of oxygen into the breathing bag as the bag fills up.
Release the bypass button when the needle reads 1.7 LPM on the outside red scale. The needle should then settle somewhere between 1.4 and 1.7 LPM, indicating that the dosage device is allowing approximately 1.5 LPM of oxygen to constantly flow into the breathing bag.
i. Whistle Activation Test- First, remove the plug from the relief valve vent.
What you are going to do now is check to see that the warning whistle sounds when it is supposed to sound.
Remember, the whistle is designed to alert the wearer when the oxygen in the cylinder is down to 20 to 25 percent of the original cylinder pressure.
In testing the warning device, you should first close the oxygen cylinder valve by placing two fingers on the knob, pulling it out, and rotating it clockwise until you meet resistance. Do not overtighten the valve. Then check the pressure on the chest pressure gauge. It should move towards zero; and the whistle should sound when the needle reads 20 to 25 percent of the full cylinder pressure.
j. Whistle Duration/Pressure Gauge Shutoff Test- Now that you've tested the whistle to determine when it sounds, you'll want to determine how long it sounds. Remember, it should sound for 20 to 60 seconds.
At the same time, you will be testing the pressure gauge shutoff valve to see that it closes properly.
Before you begin this test, switch the tester to negative pressure pumping.
To get the whistle to sound, lift the pressure gauge shutoff lever, open the oxygen cylinder valve (again with two fingers) and start the stopwatch. The whistle should sound for 20 to 60 seconds.
Now check the chest pressure gauge. It should read zero, indicating that the shutoff lever properly closes the line leading to the gauge.
When you're finished with the test, make sure to return the shutoff lever to its original position.
k. High and Medium Pressure Leak Test- Now you're finished using the tester and are ready for the final test: testing the high and medium-pressure lines for leaks if the tester has indicated that a leak exists.
With the cylinder valve still open, coat the high- and medium-pressure lines and connections with a soap lather or a leak detector solution, and look for bubbling of the solution. Where there are bubbles, there is a leak.
There is also another way of testing for high-pressure leaks: Turn on the apparatus and plug the preflush/dosage line with a special plug (R 1/4"). After the preflush is complete, shut off the cylinder valve and tap on the test gauge with your finger.
After 5 minutes, open the cylinder valve again and observe the test gauge for any noticeable movement of the needle. If the needle jumps up, this would indicate that oxygen leaked out during the 5-minute period.
That concludes the testing. You can now close the cylinder valve, unless you are going directly into training or rescue operations.