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Instructor Guide
Session Reference: 2-1
Topic: Self Contained Breathing Apparatus - Lecture/Practical
Level of Instruction:
Time Required: 3 Hours
Materials: Overhead Projector, MFRI OHT's, SCBA (Variety of Types)
References: IFSTA Self Contained Breathing Apparatus, 2nd Ed.; IFSTA Essentials, 3rd Ed.;
Iowa Fire Service Institute, Advanced Breathing Apparatus Techniques
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Preparation:
Motivation:
Important to be able to correctly don the breathing apparatus and know what to do in emergency situations - your life depends on it!!!
Objective (SPO): 2-1, MFRI Overhead: T-PEAF-2-1-1
The student will be able to demonstrate the procedures for putting in and taking out of service self contained breathing apparatus from memory, without assistance, to an accuracy of 70% and the instructor's satisfaction.
Overview: MFRI Overhead: T-PEAF-2-1-2
Self Contained Breathing Apparatus
- Types/Functions of Breathing Apparatus
- Components
- Care and Maintenance
- Donning, Doffing, and Operations
- Controlled Breathing Techniques
- Changing Cylinders
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Session 2-1
Self Contained Breathing Apparatus - Lecture/Practical
SPO 2-1 The student will be able to demonstrate the procedures for putting in and taking out of service self contained breathing apparatus from memory, without assistance, to an accuracy of 70% and the instructor's satisfaction.
2-1-1 Identify the types and functions of self-contained breathing apparatus.
2-1-2 For each component of the SCBA, identify its function, safety feature, and limitations. (NFPA 472, 3-4.3.6)
2-1-3 Demonstrate and document the cleaning, sanitizing, and inspection of SCBA. (NFPA 472, 3-4.3.7)
2-1-4 Demonstrate donning and doffing the SCBA while wearing full protective clothing and ensure that it is ready for safe use. (NFPA 472, 3-4.3.8, 3-4.3.9)
2-1-5 Demonstrate controlled breathing techniques to utilize during work and emergency conditions.
2-1-6 Demonstrate changing the cylinder on an SCBA assembly.
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Instructional Guide
I. Types and Functions of SCBA (2-1-1), MFRI Overhead: T-FFI-8-1-23
A. Open circuit/positive pressure (also called safety pressure or pressure demand),
MFRI Overhead: T-FFI-8-1-24
1. Self contained
a. Method of operations
1) Compressed air from cylinder is supplied to wearer
a) Inhalation opens valve in regulator
b) Regulator allows air to flow to facepiece,
MFRI Overhead: T-FFI-8-1-25
c) Exhalation closes valve in regulator, stopping flow and opens exhalation valve in facepiece to atmosphere
2) Air from cylinder is allowed to pass through regulator. Upon inhalation, pressure is reduced in facepiece. Regulator supplies more air to compensate for pressure drop. Exhalation valve forced closed by spring tension causing slight pressure buildup inside facepiece
a) Maintains slightly higher than atmospheric pressure
b) Prevents leaks from outside into facepiece
b. Advantages
1) Quick operation
2) Intermittent use
3) Simple to use
4) Air supply to wearer is sufficient
5) Air supply independent of environment
6) Recharge cost low
7) Return to service is quick
c. Disadvantages
1) Heavy (24-36 lbs.)
2) Bulky
3) With improper seal, air supply may be used up slightly faster
4) Actual time of use in about half of rated time. Depends on
a) User's physical condition
b) User's size
c) Workload
d. Side effects of positive pressure breathing
1) Breathing under positive pressure causes increased depth of breathing (up to seven times that of normal)
2) Promotes better gas exchange in lungs
3) Increases work requirements to exhale - must exhale against pressure
4) Lungs become hyperinflated
2. Airline equipment
a. Air supplied through a long (up to 300') high pressure hose
b. Large tanks of compressed air or a compressor to supply the facepiece are required
c. Positive pressure
d. Emergency escape feature (small SCBA tank - 5 minutes)
e. Restricted movements due to air line
f. Must exit same way entry was made
g. Lightweight - not bulky
B. Closed circuit/positive pressure
1. Recycles exhaled breath after removing carbon dioxide and adding supplemental medical grade oxygen, MFRI Overhead: T-FFI-8-1-26
2. Carbon dioxide and moisture is removed by a canister of sodium bicarbonate, known as "scrubber", MFRI Overhead: T-FFI-8-1-27
3. No oxygen/exhaled air used in system is released outside the facepiece, except for venting of excessive pressure
4. Positive pressure is maintained by releasing oxygen at a greater rate than is needed for breathing alone
5. Advantages
a. Actual time of use is very close to rated time
b. Quick operation
c. Meets wearer's air requirements
d. Air supply independent on environment
e. Lightweight (20 lbs.)
f. Less bulk
6. Disadvantages
a. Medical oxygen may be more difficult to acquire on short notice
b. Requires "scrubber" to be changed with each oxygen cylinder change. Dated - must be used by expiration date
c. Breathing air is somewhat "warmer" to inhale compared to open circuit systems
1) Recycled air is at body temperature or higher due to chemical reaction
2) Chemical reaction with moisture generates heat
7. Side effects of closed circuit/positive pressure breathing same as open circuit systems
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NOTE: For practical portion, have students get the equipment ready.
NOTE: Students should be encouraged to bring to class their own equipment with which they are familiar. The instructor should be familiar with all types of equipment that may be in class prior to the session.
1. Open case and have students study how apparatus is placed in the case (to ensure correct placement after class)
2. Remove apparatus; (have student check number on box, harness, and facepiece - all should be the same)
a. Cylinder up
b. Cylinder valve at feet
c. Straighten and extend all straps
d. Facepiece on right of cylinder
3. Place case behind chair
4. Check apparatus to see if the cylinder valve is off
a. Check regulator gauge to see that it reads "0" (zero) pressure
b. Check mainline valve and by-pass to ensure they are off. If not off, the instructor should crack mainline to bleed air
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II. Components of SCBA (2-1-2)
A. Cylinder
1. Types
a. 30 minute low pressure system (actual use = 15-20 min.)
1) Average volume - 45 cu. ft. at 2,216 psi
2) Average unit weight with steel cylinder = 33 pounds
3) Average unit weight with aluminum cylinder = 33 pounds
4) Average unit weight with composite cylinder = 25 pounds
a) Aluminum with hoop fiberglass wrap
b) Aluminum with full fiberglass wrap
b. 30 minute high pressure system (actual system use = 15-20 min.)
1) Volume = 45 cu. ft. at 4,500 psi
2) Cylinder is about half the size of a 30 minute low pressure cylinder, providing smaller firefighter profile
3) Average unit weight = 23 pounds
c. 45 minute high pressure system
1) Volume = 60 cu. ft. at 3,000 psi
2) Cylinder is about same size as 30 minute low pressure
3) Average unit weight = 25 pounds
d. 60 minute high pressure system
1) Volume = 88 cu. ft. at 4,500 psi
2) Cylinder is slightly larger than 30 minute low pressure
3) Average unit weight = 30 pounds
2. Cylinder valve and gauge - (Note pressure on student's cylinder and explain why MFRI does not fill them to recommended pressures)
3. Locking device - cylinder valves may have locking devices, but are no longer required
4. Markings - serial number, test date, DOT, ICC and NIOSH markings
5. Safety or over-pressure plug - if, during filling, the cylinder is over filled, a small metal disc will rupture and the air will escape to the outside (safety device)
6. A full cylinder rated at 30 minutes by the NIOSH/MSHA (Federal non-fire service agencies) will last about 15 to 20 minutes depending on
a. Physical condition
b. Psychological stability or make up
c. Ability to control breathing
d. Training and experience
e. Work activity
f. Other factors
B. Harness - a device to hold and carry the breathing apparatus assembly on the back of the emergency services responder
1. Backplate - holds the cylinder in place with a cylinder strap
2. Waist strap - to hold the harness on the back and to prevent the assembly from sliding
3. Chest strap - to hold the should straps in position
4. Shoulder strap - straps to carry the assembly on the back
5. Adjustment straps - used to adjust the harness assembly to a comfortable position on the back
6. Approval label - NIOSH/MSHA
C. Lower pressure warning device
1. SAFETY FEATURE
2. A device to warn you that your air supply is running low
a. Activates at approximately 25% of rated working pressure (3 to 5 minutes) of air left in the cylinder, depending on
1) Your physical condition
2) Your psychological stability or make-up
3) Your ability to control breathing
4) Your training experience
5) Your work activity
6) Other factors
b. Locations and types of device are different on some apparatus
1) Point out difference in locations
2) Point out difference in types
a) Bell
b) Whistle
c) Vibrator
c. The alarm will continue to operate if there is less than 1,000 psi in low pressure cylinders and 1,400 psi in high pressure cylinders
D. High pressure hose
1. Carries air, at cylinder pressure, from cylinder to regulator
2. Connector for high pressure hose - hand-tight
a. Does not require wrench
b. Should be finger tight. If the connector still leaks, snug up with hand. If it still leaks, check "O" ring. Never overtighten. It will damage "O" ring
c. Keep spare "O" ring with apparatus, replace as necessary
d. Never use wrench, or full hand power on connector
E. Regulator assembly - a device which reduces the high pressure air from the cylinder to a breathable low pressure (50 psi) air for the facepiece
1. Gauge - tells how much air is remaining in the cylinder
a. Have student compare cylinder and regulator gauge, go by lowest pressure
b. Should never be more than 100 psi difference. If so, have checked by service personnel
2. Mainline valve -
a. Yellow, gold, or silver colored valve
b. Normally stored in the "CLOSED" position and used in the "OPEN" position
NOTE: Current NIOSH/OSHA regulations do not permit "ON/OFF" switches on SCBA. Units with these switches must be converted. Units that have not yet been converted should have the switch left in the "ON" position, with the mainline valve stored in the "CLOSED" position.
3. Locking device - locking device found on mainline only may differ between manufacturers. The student must be familiar with this locking device, especially where positive pressure is used
4. Emergency by-pass valve (SAFETY FEATURE)
a. Usually colored red
b. Shape will differ from mainline valve
c. Top valve - closest to the heart
d. Permits cylinder air pressure to flow directly to facepiece
e. Reasons to use
1) Used for escape if the regulator fails to function properly
2) Overworking (not getting enough air)
3) Clears fogging in mask (or use nosecup)
NOTE: Warn students that this may waste valuable air supply.
f. Opened only on inhalation, with the main line valve placed in the "closed" position. It is normally stored in the closed position and worn in the open position
NOTE: Many of the newer high pressure systems have a purge valve but DO NOT have a by-pass valve. These regulators are designed to fail in the open position.
5. Connector, breathing tube - connects regulator to low pressure hose from the facepiece
F. Facepiece mounted regulators
1. Used on some high pressure systems
2. Same function as low pressure systems
3. No mainline valve - system is activated by purging facepiece and then inhaling
4. Does not have by-pass valve - system is designed to fail in the open position
5. Purge valve - for purging contaminants from the facepiece
6. Donning switch - shuts off air to facepiece prior to doffing
7. Locking device - to assure regulator to facepiece connection
8. Gasket - sealing regulator to facepiece
9. Gauge is independent of the regulator
G. Facepiece assembly
1. Breathing tube connector
a. Connect the facepiece to the regulator
b. Not interchangeable with other manufacturers
1) Note differences in swivel locations
2) Gasket in connectors will differ
a) MSA - flat fiber washer
b) Scott and Surviv-Air "O" Ring
2. Breathing tube or hose - allows low pressure air to flow into facepiece (approx. 50 psi)
3. Facepiece - covers/protects the face and provides for inhalation and exhalation of low pressure air
a. Inhalation valve - prevents moisture and liquids from running down the low pressure breathing tube and into regulator. All facepieces are not equipped with this device
b. Exhalation valve - allows exhaled air to leave the facepiece and stops smoke and toxic gases from entering facepiece on inhalation
1) Can sometimes become stuck, preventing exhaled air leaving by way of the exhalation valve; causes air to blow out around the face seal
2) To correct, try blowing out hard while holding facepiece tight to face
3) Positive pressure - no difference between manufacturers
a) Exhalation valve on the facepiece is equipped with a pressure balancing mechanism - air does not continuously flow, but does maintain a positive pressure inside the facepiece
b) A positive pressure facepiece must be worn with a positive pressure regulator for the system to operate properly
c) Speaking diaphragm - not on all facepieces
d) Nose cup - deflects exhalation away from lens to prevent fogging
e) Spider or facepiece harness - a strap which holds the facepiece firmly against the face. Be sure straps are fully extended when putting away (check for wear and tear)
III. Care and Maintenance (2-1-3)
A. After use maintenance
1. Recharge/replace cylinder if at 90% capacity or less (1,850 psi if 2,216 cylinder)
2. Inspect "O" rings and gaskets
3. Inspect facepiece and low pressure hose
4. Clean facepiece and hose
a. Submerge in approved cleaner/disinfectant with warm water
b. Rinse in warm water
c. Air dry - do not connect to regulator when low pressure hose is wet
5. Inspect and clean harness
6. Check operation of all gauges and valves
B. Cylinder recharging
C. Recommended daily inspection and maintenance
1. Cylinder pressure
2. Position of mainline and by-pass valves
3. High pressure coupled to cylinder - should be finger tight
4. Operation of low pressure alarm
a. Open cylinder valve
b. Alarm should activate when pressure builds up and stops afterward
c. Check gauge on regulator
d. Relieve pressure on the by-pass valve - crack slightly
e. Note operation of alarm
1) After alarm operates, slowly open by-pass 1/4 turn. Note pressure at which alarm starts to sound. Should be 1/4 of the working pressure and continue until pressure reaches approximately 100-200 psi
2) After alarm stops, close by pass valve
5. Straps fully extended
6. Check complete unit
a. Cracks
b. Cuts
c. Abrasions
d. Dents
e. Missing parts
7. Cylinder secured to backplate and harness
D. Monthly inspections and maintenance - same as daily/weekly plus
1. Stretch and manipulate all rubber parts to maintain pliability
2. Test cylinder and valves for air tightness with soapy water solution
3. Don and operate unit and check
a. Airflow
b. Noises
c. Gauge readings
d. Exhalation valve
e. Anything else the manufacturer recommends
E. Defective units
1. Remove from service
2. Tag
3. Repair or replace
IV. Donning and Doffing Procedures/Safety Checks (2-1-4)
A. Four-step donning
1. Pre-donning inspection
2. Donning
3. Safety check
4. Operation
B. Pre-donning inspection
1. All straps (harness and facepiece)
a. Take out twists
b. Fully loosened
2. Valves
a. All regulator valves in the "closed" position
NOTE: Current OSHA/NIOSH regulations do not allow an "ON/OFF" positive pressure switch. Therefore switches should be kept in the "ON" position at all times and mainline valve used in the same manner as regulators with full time positive pressure. Advise students that regulators with switches should be converted to meet the standard by qualified service personnel.
b. All connections hand tight
3. Read cylinder gauge (out loud during drills)
4. Open cylinder valve
a. Listen for low pressure
1) Will not activate if regulator has not been bled from previous use
2) Remind students not to use SCBA if warning device does not activate
b. Read regulator gauge and compare to cylinder gauge
C. Donning (three suggested methods)
1. Coat method
a. Stand or kneel at valve end of cylinder
b. With left hand, cross over backplate and grasp shoulder strap that will be worn on left shoulder
c. Control the regulator (if applicable) with right hand
d. Lift harness assembly and swing so that grasped shoulder strap is resting on left shoulder while right shoulder strap comes across the back to rest on right shoulder
e. Secure harness
2. Crossed-arms coat method
a. Kneel at the valve end of cylinder
b. Cross arms, left over right and grasp shoulder straps at the top of harness - left hand holds left strap, right hand holds right strap
c. Lift SCBA and swing unit around right shoulder. Raise left arm and bring unit behind head and onto back
d. Slide hands down straps to shoulder strap buckles
e. Secure harness
3. Over the head
a. Kneel at the end opposite the cylinder valve
b. Grasp backplate/cylinder with both hands
c. Lift harness assembly overhead - let straps hand free, they will fall into place over the elbows
d. Slide harness onto back in proper position
e. Secure harness according to manufacturer's procedure
4. Don facepiece (five piece webbing)
a. Chin first
b. Place webbing over head
c. Secure straps
1) Neck
2) Temple
3) Top
d. Helmet chin straps must be used
5. Donning facepiece with mesh/hairnet and two straps
a. Chin first
b. Place mesh over head
c. Secure
1) Tighten neck straps
2) Stroke harness firmly down back of head
3) Re-tighten neck straps
6. Facepiece with direct regulator connection (after donning facepiece)
a. Check gasket on regulator
b. Mount and lock regulator. Safety check for seal - inhale for 10 seconds prior to activating system
c. Activate system
D. Safety check
1. Facepiece seal (mainline closed)
a. Connect the breathing tube to the regulator by pushing the coupling over the regulator outlet
b. Inhale slightly and hold your breath momentarily (10 seconds)
c. Facepiece should slightly collapse and there should not be any leakage of air. If leak is suspected, disconnect facepiece - readjust facepiece and head straps and retry
d. Exhalation valve check
1) With hose in the regulator coupling, inhale and exhale to assure function
2) Foreign matter may lodge in spring assembly
2. Mask mounted regulator
a. Regulator is mounted, locked in place
b. With no air flow, the student is to inhale and hold for 10 sec.
E. Operations
1. Connect low pressure hose to regulator according to manufacturer's procedure
2. Open mainline valve
3. Inhale to check regulator gauge function. Gauge reading should be equal to or within 100 pounds. Believe the lesser of the two
4. Positive pressure check - break seal with two fingers; check for outward rush of air
5. Open by-pass or purge valve to check for function
NOTE: Make sure that the student's helmet is sitting properly on the head, and chin straps are secure. Many helmets are designed to adjust to SCBA facepieces. The front headband in some helmets may be pushed up into the helmet (i.e., Cairns 660 model)
F. SCBA doffing
1. Facepiece doffing
a. Shut off mainline valve
b. Remove low pressure hose from regulator
c. Loosen facepiece spider straps by pulling forward the buckles provided
d. Pull facepiece down so as to allow the chin strap to be removed, then lift facepiece over head. Finish loosening spider straps as in "ready position"
e. Place in a clean area by right foot so as to protect the lens from scratching and the inside of facepiece and breathing tube from becoming wet or contaminated from dirt, dust, grit, or liquids
f. Clean facepiece as described by manufacturer or see cleaning and stowing
2. Doffing the harness
a. Unbuckle waist and chest straps where provided
b. Loosen waist and chest straps and fully let out using appropriate buckles. Loosen and let out shoulder straps all the way. Remove right shoulder strap from shoulder
c. Reach to left shoulder strap with left hand
d. Slide harness off left shoulder holding regulator in right hand
e. Place harness on floor with cylinder towards floor
f. Extend all straps on the harness assembly
g. Lay out straps and check to see that they are not tangled or twisted; straighten as necessary
h. Shut off cylinder and bleed with mainline valve
NOTE: Upon completion of the last donning and doffing drill, have students remain in SCBA and sit on floor. Have them practice controlled breathing methods as they are described in next session.
V. Controlled Breathing Techniques (2-1-5)
A. Breathing must be kept on a conscious level. Subconscious patterns result in breathing only through the mouth or nose
1. Nose breathing results in
a. Short breaths
b. Lungs not filled to capacity
2. Mouth breathing results in
a. Rapid breathing
b. Body cannot take full advantage of oxygen before exhalation
B. Suggested patterns
1. In through nose - out through mouth
a. Easy to learn and remember
b. Close to normal pattern when speaking
c. Technique
1) Breathe in slow and deep
2) Hold in lungs 3-4 seconds for maximum oxygen/carbon dioxide exchange
2. In through mouth - out through nose
a. Allows for good air exchange without holding breath
b. Points exhaled air down away from lens decreasing fogging
c. Technique
1) Inhale rapid and full
2) Exhale slowly
3) Best method for strenuous work
3. Five second count method
a. Technique:
1) Inhale for 5 sec. using either of first two methods - slowly and fully
2) Hold for 5 seconds
3) Exhale for 5 seconds
4) Repeat cycle
b. Best for short rest breaks
NOTE: The pattern chosen by the user must consciously be regarded as a formalized ritual which must be practiced in and out of the breathing apparatus until it becomes second nature. It must be used every time SCBA is used.
4. Skip breathing
a. Emergency only - for conservation of air
b. 30 minute SCBA may be extended to two hours
c. Technique
1) Inhale fully
2) Hold breath for normal exhalation time
3) Take additional breath before exhaling
4) Exhale slowly
5) Repeat cycle
d. Important to remain mentally and physically calm
VI. Changing Cylinder Procedure (2-1-6)
A. Spread apparatus out on floor with cylinder up
B. Point cylinder valve at feet
C. Extend and straighten all straps
D. Turn cylinder valve off
E. Bleed air off regulator by turning slowly and opening and closing the mainline valve
F. Disconnect H/P hose from cylinder (Check "O" ring in H/P connector)
G. Loosen cylinder strap or holding device
H. Remove cylinder from backplate
I. Insert new cylinder to cylinder stop (depends on manufacturer)
1. In older cylinders - rotate valve threads approximately 30 degrees downward toward floor
2. On newer cylinders - valves have threads at an angle to relieve stress off of high pressure line
J. Tighten cylinder holding device; securing cylinder to back plate
K. Check "O" ring in H/P connector before connecting high pressure hose
L. Check proper position of regulator and straps by donning apparatus
M. Check to see if regulator valves are in normal position
1. Yellow, gold, or silver (mainline) closed
2. Red (by-pass) closed
N. Turn cylinder valve on to check for leaks
O. Bleed system as in E above
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NOTE: Instruct students in the following cleaning and stowing procedures:
- Cleaning: Take a small amount of the cleaning liquid provided and wet the material provided for cleaning. Wipe out the inside of the facepiece to remove all sweat and other foreign materials. Allow to dry. Check once again to be certain that all foreign material has been removed and that the inside of the facepiece is dry. Check the cleanliness of the breathing tube connector, the regulator, and the exhalation valve for dirt and other foreign material and clean as necessary
- Stowing Apparatus: After changing the cylinder, the apparatus is now ready to be stowed in the case. Ensure that the cylinder is filled and that all straps are extended
- Case: Lift harness with shoulder straps and lower into apparatus carrying case. Make sure that the cylinder is inserted in the correct direction. Place regulator in the appropriate area in the case and then fold straps neatly in the area where they would normally lay. Place facepiece into case so that there is as little deformity as possible. Ensure that both the cylinder and facepiece numbers correspond to the number on the case
- Stowing must be done under the supervision of an instructor
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SUMMARY
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Review: MFRI Overhead: T-PEAF-2-1-3
Self Contained Breathing Apparatus
- Types/Functions of Breathing Apparatus
- Components
- Care and Maintenance
- Donning, Doffing, and Operations
- Controlled Breathing Techniques
- Changing Cylinders
Remotivation:
Remember to use SCBA at all times - it is the emergency services responder's best friend and lifeline.
Assignment:
Practice donning and doffing SCBA
Practice wearing SCBA.
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Evaluation:
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