1.
Normal percent of oxygen in the air is:
Correct Answer
B. 21%
Explanation
The normal percent of oxygen in the air is 21%. This is because the Earth's atmosphere is composed of various gases, with oxygen being the second most abundant gas after nitrogen. Oxygen is essential for the survival of most living organisms, including humans, as it is used in the process of respiration. The 21% oxygen concentration in the air is considered optimal for sustaining life.
2.
General symptoms of exposure to respiratory hazards include:
Correct Answer
D. All of the above
Explanation
The correct answer is "All of the above" because general symptoms of exposure to respiratory hazards can include impaired senses or unusual sensations, mental confusion or dizziness, and sometimes there may be no symptoms at all. This means that individuals who are exposed to respiratory hazards may experience any combination of these symptoms or even no symptoms at all.
3.
Symptoms of exposure to respiratory hazards may occur:
Correct Answer
D. All of the above
Explanation
Exposure to respiratory hazards can lead to symptoms that may occur immediately after the exposure, such as coughing or difficulty breathing. However, it is also possible for symptoms to manifest hours or even days after the exposure, depending on the specific hazard and individual factors. Therefore, all of the options listed are correct, as symptoms can occur immediately, hours later, or even days later after being exposed to respiratory hazards.
4.
The purpose of wearing an SCBA is to:
Correct Answer
C. Protect the respiratory tract from toxic and/or superheated products
Explanation
The purpose of wearing an SCBA is to protect the respiratory tract from toxic and/or superheated products. This is important because in firefighting situations, there is a high risk of exposure to harmful substances and smoke inhalation. The SCBA provides a supply of clean, breathable air to the firefighter, allowing them to safely navigate through hazardous environments and avoid respiratory damage. It also helps to prevent the inhalation of superheated gases, which can cause serious burns to the respiratory system.
5.
Breathing consists of:
Correct Answer
A. Inhalation & Exhalation
Explanation
Breathing consists of both inhalation and exhalation. Inhalation is the process of taking in air, while exhalation is the process of expelling air. These two processes work together to ensure the exchange of oxygen and carbon dioxide in the body, allowing for proper respiration and the supply of oxygen to the cells. Wearing a positive pressure SCBA is not a part of normal breathing, and holding your breath for a long time and taking quick breaths off the SCBA is not a recommended practice for efficient breathing.
6.
What is the reason that the use of standard eyeglass frames is not recommended while wearing an SCBA?
Correct Answer
B. They will prevent face piece seal at the temples
Explanation
The use of standard eyeglass frames is not recommended while wearing an SCBA because they will prevent a proper face piece seal at the temples. This is important because a secure seal is necessary to ensure that the SCBA is functioning effectively and protecting the wearer from harmful gases or particles.
7.
The actual time of use that a wearer can get from an SCBA depends on:
Correct Answer
D. All of the above
Explanation
The correct answer is "All of the above." The actual time of use that a wearer can get from an SCBA (Self-Contained Breathing Apparatus) depends on various factors such as the user's physical condition, size, and workload. These factors can affect the rate at which the user consumes air and therefore determine the duration for which the SCBA can provide breathable air.
8.
Side effects of positive pressure breathing are:
Correct Answer
C. Breathing under positive pressure causes increased depth of breathing
Explanation
Breathing under positive pressure causes increased depth of breathing because positive pressure applied to the airways during inhalation helps to expand the lungs more fully, allowing for a greater volume of air to be taken in. This can lead to increased oxygenation of the blood and improved ventilation. However, it can also put strain on the respiratory muscles and potentially cause barotrauma or damage to the lung tissue if excessive pressure is applied.
9.
Advantage or advantages of wearing an SCBA are:
Correct Answer
B. Air supply is independent of environment
Explanation
Self-contained breathing apparatus (SCBA) are employed to safeguard individuals from oxygen depletion, as well as to provide protection against dust, gases, and vapors. These devices find application in various settings, including plants, vessels, firefighting scenarios, and tunnels.
10.
When the low pressure warning device activates:
Correct Answer
C. Both a & b
Explanation
When the low pressure warning device activates, it indicates that there is approximately 25% of the rated working pressure of air left in the cylinder. In this situation, the wearer should notify their partner about the alarm activation and both should exit the hostile environment immediately. Therefore, the correct answer is both a & b.