Free NFPA CFPS Practice Exam with Questions & Answers | Set: 3

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

Fire alarm visible appliance source intensity is measured in candela, which is the unit of luminous intensity in a given direction. Candela is defined as the amount of light emitted by a single candle in a specific direction. The intensity of a strobe light depends on the candela rating, the flash rate, and the flash duration. The higher the candela rating, the brighter the light. The National Fire Protection Association (NFPA) and the Americans with Disabilities Act (ADA) have established minimum and maximum candela ratings for fire alarm visible appliances in different locations and applications.References:Strobe Light Requirements: Proper location of visible notification …;Handbook of Visual Notification Appliances for Fire Alarm Applications;Audible Visible Appliance Reference Guide - Fire - studylib.net

Zebra mussel

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The correct answer is B. Zebra mussel pipe obstructions are largely concentrated around the Great Lakes and Mississippi River areas. Zebra mussels are an invasive species that originated from Eurasia and were introduced to North America in the late 1980s through the ballast water of ships. They have since spread to many freshwater lakes and rivers, especially in the Midwest and Northeast regions of the United States and Canada. Zebra mussels can attach themselves to hard surfaces, such as pipes, pumps, valves, and filters, and form dense colonies that reduce or block the water flow. This can cause serious problems for industries, utilities, and municipalities that rely on water intake or delivery systems.Zebra mussels can also damage aquatic ecosystems, infrastructure, and recreation by competing with native species, altering water quality, and fouling boats and equipment12345

Class A roof coverings are the most effective in preventing the spread of fires from flying brands. Flying brands are burning embers or pieces of combustible material that are carried by the wind and can ignite other combustible materials or structures. Class A roof coverings are tested to withstand severe fire exposure from simulated fire sources, such as large burning brands, and do not produce flying brands themselves. Class A roof coverings include materials such as asphalt shingles, metal sheets, clay or concrete tiles, slate, and some types of synthetic membranes12. References:

• Class A, B, and C Roof Ratings - UL
• Fire-Resistant Roofs - Fire Safe Marin

When magnesium shavings or chips come in contact with water, they react to produce magnesium hydroxide and hydrogen gas. The chemical equation for the reaction is: 2 Mg (s) + 2 H2O (l)→2 Mg (OH)2 (aq) + H2 (g). This displacement reaction is characterized by effervescence, a vigorous reaction, and the formation of a white precipitate of magnesium hydroxide.

References:

• Reactions of Group 2 Elements with Water - Chemistry LibreTexts1
• Magnesium (Mg) and water - Lenntech2

The Fire Safety Concept Tree is a tool for systematically evaluating the fire safety performance of a building or occupancy. It consists of three main branches: fire prevention, fire protection, and fire safety management. Fire prevention aims to eliminate or reduce the occurrence of fire. Fire protection aims to control or limit the fire development and spread, and to protect the exposed occupants and property. Fire safety management aims to ensure the effective operation and maintenance of the fire safety systems and the appropriate human behavior in case of fire. Emergency response is one of the subcategories of fire protection, which includes the actions of the fire department, the building staff, and the occupants to respond to the fire emergency.References:

The two classes of fire models arephysical and mathematical. Physical fire models are scaled-down representations of real fire scenarios, using laboratory experiments and measurements to study the fire behavior and effects.Physical fire models can be used to test hypotheses, validate mathematical models, and provide empirical data for fire analysis1. Mathematical fire models are numerical or analytical solutions of the equations that govern the fire phenomena, such as heat transfer, fluid dynamics, combustion, and chemical kinetics.Mathematical fire models can be used to simulate fire scenarios, predict fire outcomes, and optimize fire protection systems2. There are two major categories of mathematical fire models: zone models and field models. Zone models divide the fire compartment into two or more homogeneous zones, such as upper and lower layers, and apply mass and energy conservation equations to each zone.Zone models are relatively simple, fast, and easy to use, but they have limitations in accuracy and applicability3. Field models solve the partial differential equations that describe the fire-driven fluid flow and heat transfer in three dimensions, using computational fluid dynamics (CFD) techniques.Field models are more detailed, realistic, and flexible, but they require more computational resources and expertise4.References:

• Fire modelling with Computational Fluid Dynamics - BRE Group
• Fire modeling programs | NIST
• interFIRE, A site dedicated to improving fire investigation worldwide.
• Computer Fire Models for Fire Investigation and Reconstruction

The background color used from the source to the outlets of a nitrous oxide medical gas system is blue. This is the standard color coding for nitrous oxide cylinders and pipelines in medical gas pipeline systems12. The color coding helps to identify the gas type and prevent accidental misconnections or cross-contamination3. The color coding also indicates the pressure and flow characteristics of the gas system4. References:

• Colour coding of copper pipes in Medical gas pipeline system according …
• Doc 177 20 Medical Gas Cylinders Colour Coding - EIGA
• Medical Gas Coding Color Chart & Explanation - Bay Corporation
• Medical gases Health Technical Memorandum 02-01: Medical gas pipeline …

titanium is the pure metal in its solid form in oxygen that has the highest ignition temperature in degrees Fahrenheit.The spontaneous-ignition temperature of titanium in the solid phase (below melting) is about 3020°F (1660°C)1.Aluminum, potassium, and zirconium have lower ignition temperatures in the solid phase, ranging from 1292°F (700°C) to 1652°F (900°C)23.References:

• IGNITION OF METALS IN HIGH PRESSURE OXYGEN2
• Combustion of Metals in Oxygen-Enriched Atmospheres3
• High-temperature oxidation and ignition of metals1

A proprietary fire alarm system is a type of fire alarm system that transmits signals that are permanently recorded at a constantly attended supervising station located either at the protected premises or at another location of the property owner. A proprietary fire alarm system is owned and operated by the property owner or the owner’s agent. A proprietary fire alarm system is intended to provide fire alarm service to a single property or a campus of related properties.References:

• NFPA 72: National Fire Alarm and Signaling Code, 2019 Edition, Section 3.3.105.11
• Fire Protection Handbook, 20th Edition, Volume 1, Chapter 7, Section 7.2.1.12