Breathing Apparatus Flashcards
What is the purpose of the respiratory system
To provide oxygen to the blood haemoglobin which is then pumped throughout the body by the heart.
Where does the transfer of gases happen in the respiratory system
Oxygen diffuses in through the alveoli (tiny air sacs surrounded by capillaries) and into the blood haemoglobin on inhale. A similar process diffuses carbon dioxide out of the blood into the lungs to be exhaled.
Symptoms of hyperventilation
Numbness
Tingling of the hand, face and feet
May feel dizzy, giddy or faint
Composition of air (before and after) inhalation
Before After
Nitrogen 78.09% 78.09%
Oxygen 20.95% 16.95%
Carbon Dioxide 0.04% 4.03%
Other gases 0.92% 0.92%
What are the 4 irrespirable atmospheres
Toxic Gases and fumes
Oxygen deficiency
Elevated temperature
Smoke
What creates oxygen deficiency
Oxygen can be displaced by other gases such as carbon monoxide.
Oxygen can be used by combustion.
At 1.28% Carbon monoxide in air how quickly can it cause death
Immediately or 1-3 minutes.
Is carbon monoxide deadly in smaller concentrations
Yes - A smaller concentration is equally a fatal if breathed for a longer period.
How much more readily does carbon monoxide combine with the haemoglobin than oxygen
Around 200 times more readily.
Effects of excess carbon dioxide
Increased breathing Vomiting Dizziness Disorientation Headache Difficulty breathing
What temperature and above should not be entered without BA
50 degrees and above will start causing damage and could result in death.
Why does smoke occur and what is it
Rarely will perfect combustion occur in the burning process this unconsumed material escapes in the form of smoke. Consists of small particles of solid or liquid matter, principally soot, carbon and liquid hydro carbons.
When does heat exhaustion occur and what comes after
Occurs when the body’s core temperature rises and there is a fluid loss of 5% and above due to perspiration.
If this is not acted upon a more serious state known as heat stoke may occur.
Symptoms of heat exhaustion
Dizziness Lethargy Nausea Abdominal discomfort Burning sensation of the skin
Symptoms of heat stroke
Cyanosis
Speech and walking difficulties
Collapse
Unconsciousness
How to prevent heat exhaustion and heat stoke
The body’s fluid level must be maintained through frequent intake of water.
What’s the function of BA
Is to enable to wearer to work in an atmosphere that would not otherwise support life.
What BA system does ACTF&R use
Open circuit demand and positive pressure breathing apparatus.
Meaning air is supplied by a cylinder and exhaled breath is passes to the atmosphere.
What is the nominal effective life of a BA work set and Escape set
Work set have a nominal effective life of exceeding 15mins.
Escape sets have a nominal effective life of less than 15mins.
Define each type of cylinder duration
Full duration - is the time taken for a full cylinder to fall to 1mPa at a rate of 40L/pm.
Working duration - is the time taken from full to when the warning whistle sounds.
Safety margin - is the time taken from when the warning whistle sounds to 1mPa.
How is full duration of a cylinder calculated
Water capacity X pressure in bars X Compression factor = volume
Volume Divided by 40 L/pm will give full duration.
Full duration - 10mins will give working time.
When will the warning whistle sound
Will sound at 55bar + or - 5 bar.
Which means you have 8 - 10 minutes.
What do you do if you partners warning whistle sounds
Both exit immediately together.
Components of a BA work set
Harness and back plate Demand Valve Pressure reducer Warning whistle and pressure gauge Band and clamp Rescue second mask CEJN Cylinder Mask Cylinder connection point
