Free Practice Questions for NFPA CFPS Exam

The duration of required fire flow in public supply systems depends on the type of occupancy, construction, and exposure of the building, as well as the availability and reliability of the water supply. According to NFPA 1, Fire Code, Table 18.4.5.1.2, the minimum duration of fire flow for most occupancies ranges from 1 to 4 hours, with some exceptions for high-rise buildings, health care facilities, and special hazards. The fire flow duration is intended to provide enough water for fire suppression and exposure protection until the fire is under control or extinguished.References: NFPA 1, Fire Code, 2023 Edition, Section 18.4.5.1.2 and Table 18.4.5.1.2; NFPA Fire Protection Handbook, 21st Edition, Chapter 9, Section 9.2.2.

Wet chemical extinguishing agents, such as potassium acetate and potassium citrate, when sprayed on a grease fire, extinguish the fire by smothering and cooling. The wet chemical agent reacts with the hot grease and forms a layer of soap-like foam on the surface of the fat, which acts as an insulation between the hot grease and the atmosphere, preventing the escape of combustible vapors and oxygen supply.The wet chemical agent also absorbs heat from the grease and lowers its temperature below the ignition point12

References:

What is the Difference Between a Wet and Dry Chemical Fire …

Wet Chemical (Class K) Fire Extinguisher - Portable - WFX

According to NFPA 72, the maximum sound pressure level (SPL) for a fire alarm system is 110 dBA at the minimum hearing distance from the audible appliance1.However, this limit can be exceeded if the sound pressure level measured 2 000 mm above floor level is not more than 100 dBA2. Sound pressure level is a measure of the intensity of sound at a given point in space, expressed in decibels (dB). The higher the SPL, the louder the sound.For comparison, a normal conversation is about 60 dB, a jet engine is about 140 dB, and a gunshot is about 160 dB3.References:Sound Pressure Levels - NFPA;NFPA fire alarm sound level - EntirelySafe.com;Subsection 907.5 - Occupant notification systems - Casetext;How Loud Is a Fire Alarm In Decibels (dB)? With Noise Comparison Chart;The Ontario Building Code | Audibility of Alarm Systems.

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Detectors using the photoelectric principle do not use a small amount of radioactive material. This is a false statement about smoke detectors. Detectors using the photoelectric principle use a light source and a light sensor to detect the presence of smoke. When smoke enters the detection chamber, it scatters the light and triggers the alarm.Detectors using the photoelectric principle are more responsive to low-energy (smoldering) fires that produce large smoke particles12.

Detectors using the cloud chamber principle also use the photoelectric principle. This is a true statement about smoke detectors. Detectors using the cloud chamber principle use a sealed chamber that contains a supersaturated vapor. When smoke enters the chamber, it causes the vapor to condense into droplets that reflect light. The light is then detected by a photoelectric sensor that activates the alarm.Detectors using the cloud chamber principle are very sensitive to small smoke particles34.

Detectors using the ionization principle provide somewhat faster response to high-energy (open flaming) fires. This is a true statement about smoke detectors. Detectors using the ionization principle use a small amount of radioactive material that ionizes the air in the detection chamber. When smoke enters the chamber, it reduces the ionization and the electric current. The drop in current is then detected by a circuit that activates the alarm.Detectors using the ionization principle are more responsive to high-energy (open flaming) fires that produce small smoke particles12.

Detectors using the photoelectric principle provide somewhat faster response to low-energy (smoldering) fires. This is a true statement about smoke detectors. Detectors using the photoelectric principle use a light source and a light sensor to detect the presence of smoke. When smoke enters the detection chamber, it scatters the light and triggers the alarm.Detectors using the photoelectric principle are more responsive to low-energy (smoldering) fires that produce large smoke particles12.

Two-dimensional models are not a common type of road tunnel fire models. Most road tunnel fire models are either one-dimensional, zone, or field models. One-dimensional models use a simplified approach to describe the fire and smoke behavior along the tunnel axis, assuming uniform conditions across the tunnel cross-section. Zone models divide the tunnel into two or more zones, each with uniform properties, and apply mass and energy conservation equations to each zone. Field models use computational fluid dynamics (CFD) to solve the governing equations for mass, momentum, energy, and species transport in a three-dimensional grid, capturing the spatial and temporal variations of the fire and smoke phenomena. Two-dimensional models are rarely used for road tunnel fire simulations, as they cannot account for the complex three-dimensional effects of fire and ventilation in tunnels.

References:Design Fires in Road Tunnels | The National Academies Press;CFD Modelling of Fire Ventilation in Road Tunnels - Academia.edu;Findings of the International Road Tunnel Fire Detection Research …1

An as built plan review is a type of plan review that may provide information about a modification such as the removal of an abandoned underground flammable liquid tank. An as built plan review is conducted after the construction or alteration of a building or system is completed and before the final approval or acceptance by the AHJ. An as built plan review verifies that the building or system conforms to the approved plans and specifications and complies with the applicable codes and standards. An as built plan review may also identify any changes or deviations from the original plans that occurred during the construction or alteration process, such as the removal of an underground tank.References:

NFPA 1: Fire Code, 2018 Edition, Section 1.12.8.1.11

Fire Protection Handbook, 20th Edition, Volume 1, Chapter 5, Section 5.2.3.42

The use of an exhaust to an abatement system during the large-scale tests made the test results difficult to interpret for use in field applications. The exhaust system was used to reduce the environmental impact of the tests, but it also altered the natural buoyancy-driven flow of the smoke and heat through the vents and draft curtains. This created a pressure difference between the inside and outside of the test building, which affected the performance of the sprinklers, vents, and draft curtains. Therefore, the test results may not accurately reflect the conditions that would occur in real buildings without an exhaust system.

References: Fire Protection Handbook, 20th Edition, Volume 1, Chapter 8, Section 8.3.11; Sprinkler, Smoke and Heat Vent, Draft Curtain Interaction: Large Scale Experiments and Modeling2.

Smoke detector

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The smoke detector type that contains a small amount of radioactive material and functions by sensing a decrease in conductance of the air when smoke particles enter the chamber is theionization smoke detector. Ionization smoke detectors use a small amount of americium-241, a radioactive element, to ionize the air molecules inside a sensing chamber. This creates a low-level electric current between two electrodes. When smoke enters the chamber, it disrupts the ionized air and reduces the current flow. This triggers the alarm to sound.Ionization smoke detectors are more sensitive to small particles of smoke, such as those produced by flaming fires1.However, they may also be more prone to false alarms from cooking or steam, and they require proper disposal of the radioactive source2.

References:

Smoke Detector Types: Which Type of Smoke Detector Is Best? - X-Sense

How Does Your Smoke Detector Work? - ThoughtCo