Ace Your CFPS Fire Protection Specialist Exam

The ratio of the weight of a solid or a liquid substance to the weight of an equal volume of water is referred to asspecific gravity. Specific gravity is a dimensionless quantity that is defined as the ratio of the density of a substance to the density of the water at a specified temperature.The density of water at 4 0C is commonly used as a reference point1. Specific gravity can be calculated using the following formula:

SG=fracrhosubstance​rhoH2​O​

where rhosubstance​ is the density of the substance and rhoH2​O​ is the density of water. Specific gravity can be used to compare the relative densities of different substances and to determinewhether a substance will sink or float in water.A substance with a specific gravity less than 1 will float in water, while a substance with a specific gravity greater than 1 will sink in water2.

For example, the specific gravity of gold is 19.3, which means that gold is 19.3 times denser than water. Therefore, gold will sink in water. The specific gravity of ice is 0.92, which means that ice is 0.92 times denser than water. Therefore, ice will float in water.

References:

• Specific gravity | Formula, Units, & Equation | Britannica
• Specific Gravity - Definition, Calculation, Solved Examples, FAQs - BYJU’S

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

According to the Consumer Products Safety Commission (CPSC), the most common type of fabric used on upholstered furniture is cellulosic. Cellulosic fabrics are made from natural fibers derived from plants, such as cotton, linen, rayon, and hemp. Cellulosic fabrics account for about 51% of the total fabric weight used on upholstered furniture in the United States1. Cellulosic fabrics are popular because they are soft, comfortable, breathable, and versatile. However, they are also highly flammable and can contribute to the spread of fire if ignited2. Therefore, the CPSC has established a flammability standard for upholstered furniture that requires cellulosic fabrics to pass a smolder resistance test3. References:

• Upholstered Furniture Business Education | CPSC.gov
• Fire Fighting Foams - Chemguard
• Standard for the Flammability of Residential Upholstered Furniture

Fire pump

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A suction in-line fire pump has a pressure range that can exceed 300 psi (2,068 kPa). This type of pump is a centrifugal pump that is installed in a vertical position with the suction and discharge connections in the same line. The pump is designed to handle high pressures and flows, and it is suitable for high-rise buildings and other applications that require high head.According to NFPA 20, Standard for the Installation of Stationary Pumps for Fire Protection, a suction in-line fire pump can have a rated pressure of up to 360 psi (2,482 kPa)1.The other types of fire pumps mentioned in the question have lower pressure ranges, as shown in the table below2:

Type of fire pump

Pressure range (psi)

Pressure range (kPa)

Horizontal-end suction

40 to 150

276 to 1,034

Split case

40 to 150

276 to 1,034

Vertical turbine

40 to 150

276 to 1,034

Suction in-line

40 to 360

276 to 2,482

References:NFPA 20: Fire pump design | Consulting - Specifying Engineer;Understanding the Basics of Fire Pumps | Pumps & Systems