FREE NFSI Firefighting Knowledge Questions and Answers
Which of the following types of fire extinguishers is typically suitable for use on fires involving combustible materials such as wood, paper, and cloth?
Explanation: Class A fire extinguishers are designed to extinguish fires involving ordinary combustible materials such as wood, paper, cloth, and some plastics. They typically contain water or a dry chemical agent such as monoammonium phosphate.
Firefighters arrive at a fire in an office building. The building is a one-story building with 8 small offices. The manager of the office building was the only one standing outside the office when the firefighters arrived. He gave the firefighters the following information:
Manager: ""I arrived just before you did, so I haven't been in the building yet. You need a keycard to access the building so I am certain that the only people who could be inside at the time are my 8 employees; they occupy one office each. I let my employees govern their own schedule, so I cannot say if some of them are out of the office building on meetings or have decided to come in late today.""
As the firefighters approach the building, they see people gathered outside, it is some of the employees of the building. From the employees, they get the following information:
Christina: ""I was in Michael's office when the alarm sounded; we left the building together.""
Frank: ""I left the building as fast as I could. I know that Lance is home sick today and Brian is in a meeting downtown.""
Linda: ""I ran out immediately when I heard the fire alarm. I ran past Lisa's office on my way out, but I did not see her in her office.""
Victor: ""I was out getting my lunch. When I came back I saw the smoke and my colleagues running out of the building.""
Will the firefighters enter the building to look for people still inside?
Explanation:
There are 8 offices in the building with 8 employees. We know the following:
Christina: Evacuated
Michael: Evacuated
Frank: Evacuated
Lance: Home sick
Brian: Meeting downtown
Linda: Evacuated
Victor: Not inside
Lisa: She may be in her office, we cannot be certain, but she could still be inside.
Fire alarm regulation and sound level:
The minimum sound level of a sounder device should be 65 dB or 5 dB above background noise (if lasting more than 30 seconds) and at a frequency between 500 Hz and 1000 Hz. The maximum sound level should not exceed 120 dB.
For areas where people are sleeping, sounder devices should produce a minimum of 75 dB at the bedhead with all doors shut. In buildings likely to provide sleeping accommodations for the hearing impaired, consideration should be given to the incorporation of both audio and visual devices.
Decibel loss occurs through doors: Approximately -20 dB through a normal door, and approximately -30 dB through a fire door.
You are to install a sounder device in the hallway of the sleeping quarters onboard an old ship. There are four rooms with sleeping accommodations connected to the hallway by wooden doors. The maximum background noise level in the sleeping quarters is 69 dB. What should the sound level of the sounder device be set to?
Explanation:
The sounder device should produce a minimum of 75 dB in any bedroom with the door shut. You can calculate with a decibel loss of -20 dB through a normal door, which is the case here. Therefore you calculate with a sounder device sound level of 95 dB.
The background noise is irrelevant, if we add 5 dB to the background noise the sound level is only 74 dB and it has to be 75 dB for sleeping quarters.
It was a typical hot day in August when the emergency call came over the radio for the firefighting crew to handle a small fire that had broken out in a downtown apartment building. They hustled, as always, to make it in record time. But even in the few minutes it took them to get through the afternoon traffic, the small fire had grown to engulf the entire building. By the time firefighters arrived on the scene, most of the hundred or so residents had already made it out of the blazing seven-story inferno.
But the firefighters had to be sure everyone was safe. So Jacob, Peter, and Lisa hurriedly entered the building in their fire-retardant gear, busting down doors and checking for any remaining trapped tenants.
The roaring fire had started on the fifth floor before spreading throughout the rest of the building. Brian and Owen were working the ladder to rescue residents on the top floors, but the fifth floor was soon too far gone to risk entering. They heard no screams or sounds, but they had no way of knowing without a physical check if there was anyone left on the fifth floor.
The three firefighters on the inside made their way up to the fifth floor while the firefighters outside used ladders to look for any signs of life.
By the time Jacob and his partner made it up to the fifth floor, the fire had grown so fierce, that neither could see more than a few feet in front of them. The firefighters were forced to stop the search; if they continued, their chance of survival would be too slim, let alone finding anyone alive. As the three firefighters were making their way back down to the fourth floor, the floor above them suddenly started collapsing. Jacob was caught under the falling rubble and Lisa cut her left arm severely, leaving only one firefighter to pull Jacob out of the rubble and carry him out of the building.
The emergency call came over the radio for the fire crew to handle what type of fire?
Explanation:
The first sentence gives us the correct answer: "...the emergency call came over the radio for the firefighting crew to handle a small fire that had broken out in a downtown apartment building."
The fire did become large before the fire crew arrived, but the initial call indicated a small fire.
A significant component of any safe operation is that of a solid tactical briefing. A five-step briefing process can be used. Remember, it is just the critical information you are conveying. If practiced and used in all incidents and training, officers and firefighters should be able to touch on the five highlights in as little as 30 seconds. If more time is available, it can be used to facilitate a more thorough briefing.
1) Assignment — Make sure that everyone knows their role.
2) Current situation — Helps to update everyone's situational awareness.
3) Questions/concerns — To and from the crew, if the company officer is the only one talking, other crew members may be experiencing barriers to situational awareness.
4) How to support the assignment — This will include safety support, logistical support, and of course what you need to accomplish the task/tactic.
5) How to make the assignment safe — Will expand on the hazards present and end with how to mitigate them.
What is the most logical order of the briefing?
Explanation:
This is the correct order of the briefing:
1. Current situation — Helps to update everyone's situational awareness.
2. Assignment - Make sure that it is known to everyone. Hazard identification is here.
3. How to make the assignment safe — Will expand on the hazards present and end with how to mitigate them.
4. How to support the assignment — This will include safety support, logistical support, and of course what you need to accomplish the task/tactic.
5. Questions/concerns - To and from the crew, if the company officer is the only one talking, other crew members may be experiencing barriers to situational awareness.
The pitch of the siren of a fire truck appears to change as the truck passes us due to the Doppler effect. Of course, to an observer on the truck, the pitch does not change at all.
Since the speed of sound in air is essentially fixed, the perceived pitch of a tone is related to the wavelength of the sound. The shorter the wavelength, the higher the pitch, and vice-versa. The wavelength can be conveniently considered to be the distance between successive "crests" of the waves of pressure that constitute the sound wave.
Consider a tone emitted in the forward direction in which the fire truck is moving and consider the launching of two successive wave crests. The first crest is launched and travels in the (assumed still) air at the speed of sound (relative to the air). If the truck were not moving, the second crest would be launched after the first had traveled one wavelength. However, because the truck is moving in the same direction as the sound, the distance between the first crest and the second, at the time the second is launched, is less than previously.
That is, the wavelength between successive crests is decreased due to the motion of the truck in the same direction as the sound. Since the wavelength is decreased, but the speed of the sound in the air is unaltered (it is determined by the properties of the air), the pitch of the sound is increased in the direction in which the truck is moving.
The pitch of the siren of a fire truck appears _______ when the fire truck moves toward you, and _____ when the fire truck moves away from you.
Explanation:
The text describes how the wavelength of the sound waves appears to change as the fire truck moves. When it moves toward you, the waves are "compressed" in your direction and the wavelength is therefore decreased relative to your position. As the fire truck moves away from you again, the opposite happens: the wavelength now increases relative to your position. The text also states that a shorter wavelength will have a higher pitch and vice versa. Therefore the correct answer is that the pitch will appear higher as the truck moves toward you and lower as the truck moves away from you.
To mix a proper water foam solution, the ratio of water to foam concentrate should be 40:1.
How much foam concentrate is required to mix 1,640 gallons of water foam solution?
Explanation:
The ratio of 40:1 means that for every 40 gallons of water, there should be 1 gallon of foam concentrate, meaning that there are a total of 41 parts: 40 parts water and 1 part foam concentrate. So we have to divide 1,640 by 41 to find how much 1 part is:
1,640 / 41 = 40 gallons of foam concentrate
All Fire Department vehicles shall be regularly inspected and tested and preventive maintenance shall be conducted to ensure that vehicles are in proper operating condition.
A vehicle shall be considered unsafe and placed out of service if deficiencies are detected in one or more of the following areas: Brake system, cab and/or body mounting, steering, door latches, suspension, seatbelts, wheels or tires, windshield, windshield wipers, windshield defroster, throttle, transmission or driveline.
Other deficiencies may or may not require a vehicle to be placed out of service. Any safety-related deficiency, that does not require the vehicle to be taken out of service, shall be repaired as quickly as possible.
Driving back to the fire department after an incident you notice the first gear of the gearbox doesn't work. However, you are still able to drive the car from the second gear. When you arrive back at the fire department, how will you mark the vehicle?
Explanation:
A significant problem with the gearbox (transmission) is considered unsafe, therefore the vehicle should be marked as out of service until repaired.
1) Use a sweeping motion and aim at the base of the fire.
2) Make sure you have installed fire alarms and that you check the battery at least once a month.
3) Be sure to watch the area for a while to ensure it doesn't reignite.
4) Always stand with an exit at your back.
5) Inspect extinguishers once a month for dents, leaks, or other signs of damage.
6) Stand several feet away from the fire, moving closer once the fire starts to diminish.
7) If possible, use a "buddy system" to have someone back you up or call for help if something goes wrong.
8) Make sure you know how to use your fire extinguisher.
Which of the items on the list above would be considered part of preparing for a fire, rather than fighting it?"
Explanation:
These are the methods to prepare for a fire:
- Inspect extinguishers once a month for dents, leaks, or other signs of damage.
- Make sure you know how to use your fire extinguisher.
- Make sure you have installed fire alarms and that you check the battery at least once a month.
A house is burned down to the ground. When firefighters arrived, it was clear that the house could not be saved and the team focused on controlling the fire and isolating it to that one house.
The owners of the house afterward explained that they were visiting their neighbors and that they suddenly saw the fire through the window.
The woman explains that she is afraid that she might have left her curling iron on when she left the house.
It is soon established that the fire started in the bathroom and that it seems the curling iron is where the fire began, and that the reason for the fire was that the curling iron was left on a bath towel.
Another member of the team talks to other neighbors and he discovers that the house owner has economic troubles.
The technical team wonders how a curling iron in a bathroom of non-flammable material can start a fire as quickly as in this case. The team then finds traces of some kind of gasoline in the bathroom.
What is the most likely cause of the fire?
Explanation:
The curling iron is the ignition point of the fire. But even though the hot curling iron could have started a fire, the fire would most likely have been isolated to the bathroom, since both things were located on a bathroom floor made of materials that can't easily catch fire. Also, there are traces of gasoline - someone has clearly tried to help the fire on its way, and the couple themselves have likely done this, due to their money problems, as an act of insurance fraud.
Firefighters are trying to determine the point of origin of a fire in a small city house. The fire is known to have started as an electrical fire. When examining the house after the fire, the firefighters find the following:
The house has four rooms: A kitchen to the northwest, a living room to the northeast, a bedroom to the southwest, and a bathroom to the southeast.
The kitchen has a microwave oven, a normal oven, a refrigerator, a freezer, and a dining table with four chairs.
The living room has a 55" TV, two-floor lamps, one sofa, and a coffee table.
The bedroom has a 32" TV, one king-size bed, one large closet, and one bedside chair.
The bathroom has one radio, a sink, a toilet, and a shower.
The owners of the house had told the police that the power was turned completely off in the western part of the house due to electrical maintenance. The owners also said that they had unplugged the two-floor lamps, as they were to be replaced.
During the examination of the living room, the firefighters noted that the following items had not been damaged by the fire: the large TV, the bedside chair, and the king-size bed.
What is most likely to have been the origin of the fire?
Explanation:
All power was turned off completely in the western part of the house. The western part of the house is the kitchen and the bedroom. If there was no power to the bedroom TV and the microwave in the kitchen, neither of these could have caused the fire.
So we are left with the living room TV and the radio in the bedroom.
The large TV (living room TV) was not damaged by the fire, so it cannot possibly have caused the fire, therefore the radio must have caused the fire.