November/December 2021 Technical Challenge Answers

How Did You Do?

For each issue, AFSA’s Engineering & Technical Services Department presents technical challenges. Besides testing yourself and your co-workers, these exercises are excellent preparation for professional certification tests and also may count as continuing education hours. Check with your certification organization.  Here are the answers for the November/December 2021 issue. 

AHJ Challenge

The following questions are based on NFPA 14, Standard for the Installation of Standpipe and Hose Systems, 2019 edition.

1. Hose connections shall have external threads, for the valve size specified, in accordance with NFPA standard?
A. NFPA 14
B. NFPA 750
C. NFPA 101
D. NFPA 1963

The correct answer was D. Section 4.7.2 requires NHS threads in accordance with NFPA 1963.

2. In an 80-story building, what types of Class I standpipes are permitted? Select all that apply.
A. Automatic wet
B. Manual dry
C. Semi-automatic wet
D. Semi-automatic dry

The correct answers were A and D.

Section 5.4.1.2.2 permits only automatic or semiautomatic standpipe systems in hi-rise buildings. Semi-automatic wet systems are not a recognized system type.

3. When installing a hose valve inside of a hose cabinet what is the minimum required clearance between the hose connections and any part of the cabinet?
A. 6 inches
B. 8 inches
C. 4 inches
D. 2 inches

The correct answer was D. Section 4.6.1.1.1 requires at least a two-inch clearance between the hose connection and any part of the cabinet.

4. Except for express mains supplying higher standpipe zones, what is the maximum pressure at any point in the system permitted to be?
A. 200 psi
B. 300 psi
C. 400 psi
D. 500 psi

The correct answer was C. Section 7.2.1 restricts pressures to not exceed 400 psi at any point on the system where a hose connection is present.

Designer Challenge

The following questions are based on NFPA 14, Standard for the Installation of Standpipe and Hose Systems, 2019 edition.

1. In a building with a perimeter exceeding 900 ft, how many fire department connections must be provided for each standpipe system zone?
A. None
B. One
C. Two
D. Three

The correct answer was C. 7.12.2.2* Two fire department connections shall be provided for each zone, located either on opposite corners of the buildings where fire department apparatus access is provided or, where not possible, physically separated to the greatest extent possible for the following:
High-rise buildings
Buildings or multiple attached buildings exceeding 900 ft (274.3 m) perimeter distance

2. Which of the following characteristics would define a structure as a high-rise building?
A. Building height exceeds 75 ft from lowest level of fire department access
B. Building height exceeds the pumping capabilities of the fire department
C. Building height exceeds 60 ft from lowest level of fire department access
D. Floor of an occupiable story exceeds 75 ft from lowest level of fire department access

The correct answer was D. 3.3.9 High-Rise Building. A building where the floor of an occupiable story is greater than 75 ft (23 m) above the lowest level of fire department vehicle access. [5000, 2018]

3. When calculating the friction loss through a Class I hose valve in a dry standpipe, what primary value for equivalent length is required to be used in the hydraulic calculations?
A. 20 ft
B. 22.1 ft
C. 31 ft
D. Based on the manufacturer’s published data

The correct answer was D. This is a common misconception with friction losses in hose valves. The installation standards require the manufacturer’s listed data to be utilized, and the equivalent length in Table 8.1.3.1 should only be used as a backup. UL 668 has been updated to reflect these requirements. 8.3.1.3 Table 8.3.1.3 shall be used to determine the equivalent length of pipe for fittings and devices unless the manufacturer’s published data indicate that other factors are more accurate.

4. Which of the following devices is pilot operated and reduces the static and residual (flowing) pressure?
A. Pressure Control Valve
B. Pressure-Regulating Device
C. Pressure-Reducing Valve
D. Pressure-Restricting Device

The correct answer was A. 3.3.15 Pressure Control Valve. A pilot-operated pressure-reducing valve designed for the purpose of reducing the downstream water pressure to a specific value under both flowing (residual) and nonflowing (static) conditions.

Fitter Challenge

The following questions are based on NFPA 14, Standard for the Installation of Standpipe and Hose Systems, 2019 edition.

1. True or False – A Class II system provides 1 ½ inch hose stations to supply water for use primarily by trained personnel or by the fire department during initial response.

The correct answer was True. 3.3.22.2 Class II System. A system that provides 11∕2 in. (40 mm) hose stations to supply water for use primarily by trained personnel or by the fire department during initial response.

2. True or False – Horizontal pipe for dry standpipe pipe systems in refrigerated areas shall be pitched to drain at least 1/4 inch per 10 ft.

The correct answer was False. 6.1.3 Horizontal piping for all dry standpipe systems and semiautomatic standpipes shall be pitched to drain at least 1∕4 in. per 10 ft (2 mm/m).

3. True or False – The T-wrench for an approved roadway box shall be located within the riser or pump room closes to the roadway box.

The correct answer was False. Many Authorities having Jurisdiction will allow a T-wrench to be located in a convenient place for the site as long as it is easy to acquire.  Many times, wrenches that are left in areas may be subject to theft or may be hard to track down.  The wrench can be found with the Facilities Management Department of the site frequently.

4. True or False – Premixed antifreeze is permitted to be used to protect the standpipe system from freezing.

The correct answer was False. 6.1.2.3.1 Antifreeze solutions shall not be used to protect standpipe system piping from freezing.

ITM Challenge

The following questions are based on NFPA 25, Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, 2020 edition.

1. Listed corrosion-resistant sprinklers must be tested every __ years.
A. 3 Years
B. 5 Years
C. 10 Years
D. 15 Years

The correct answer was C. 5.3.1.1.3 Listed corrosion-resistant sprinklers installed in harsh environments shall be permitted to be tested on a 10-year basis.

2. _____ systems are involved in the majority of obstructed sprinkler fire losses.
A. Wet-Pipe
B. Dry-Pipe
C. Water Mist
D. Foam-Water

The correct answer was B. D.2.1 Pipe Scale. Loss studies have shown that dry pipe sprinkler systems are involved in the majority of obstructed sprinkler fire losses.

3. During an inspection you discover concealed sprinkler cover plates caulked to ceiling. How would you classify your finding in your inspection report?
A. Noncritical deficiency
B. Critical deficiency
C. Impairment
D. Classification of this finding is not addressed in NFPA 25

The correct answer was C. Table A.3.3.8, Chapter 5: Sprinkler Systems — Inspection

4. During a test of a diesel-driven fire pump you discover the pump does not reach its rated speed within 20 seconds, how would you classify your finding in your inspection report?
A. Noncritical deficiency
B. Critical deficiency
C. Impairment
D. Classification of this finding is not addressed in NFPA 25

The correct answer was B. Table A.3.3.8, Chapter 8: Fire Pumps — Testing


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