TEXAS DEPARTMENT OF INSURANCE TFM10 NFPA 24 EXAM QUESTIONS
AND ANSWERS VERIFIED AND WELL DETAILED ANSWERS PLUS
RATIONALES GUARANTEED PASS LATEST EXAM UPDATE
90 QUESTIONS
TABLE OF CONTENTS
# TOPIC
1 Apply NFPA 24 hydraulic and design criteria to private fire service mains and appurtenances
2 Evaluate Texas Department of Insurance statutory and rule-based requirements for fire protection system
plan review and approval
3 Diagnose common installation, testing, and maintenance deficiencies in private fire service mains and
recommend compliant corrections
4 TEXAS DEPARTMENT OF INSURANCE TFM10 NFPA 24 EXAM QUESTIONS AND ANSWERS
VERIFIED AND WELL DETAILED ANSWERS PLUS RATIONALES GUARANTEED PASS LATEST
EXAM UPDATE
5 Foundations of Fire Protection Engineering & Texas Insurance Code (TFM10 / NFPA 24)
6 Applied Fire Protection Engineering & Texas Insurance Code (TFM10 / NFPA 24)
7 Advanced Fire Protection Engineering & Texas Insurance Code (TFM10 / NFPA 24)
8 Fire Protection Engineering & Texas Insurance Code (TFM10 / NFPA 24) Review
ABSTRACT
This study document brings together 90 carefully worded exam questions drawn from TEXAS
DEPARTMENT OF INSURANCE TFM10 NFPA 24 EXAM QUESTIONS AND ANSWERS
VERIFIED AND WELL DETAILED ANSWERS PLUS RATIONALES GUARANTEED PASS LATEST
EXAM UPDATE, with the strongest emphasis placed on Apply NFPA 24 hydraulic and design
criteria to private fire service mains and appurtenances, Evaluate Texas Department of Insurance
statutory and rule-based requirements for fire protection system plan review and approval,
Diagnose common installation, testing and and maintenance deficiencies in private fire service
mains and recommend compliant corrections. Every item follows the wording style and level of
reasoning you meet in the real paper, and each one is paired with a clear rationale so the correct
choice is never a guess. Work through the set at your own pace, mark the questions that slow you
down, then come back to them until the reasoning feels automatic. Learners who revise this way
walk into the exam room recognising the pattern behind the questions instead of meeting them for
the first time. Keep going - steady, honest practice is what turns a difficult paper into a comfortable
pass.
Page 1
,Q1 APPLY NFPA 24 HYDRAULIC AND DESIGN CRITERIA TO PRIVATE FIRE SERVICE MAINS
AND APPURTENANCES
In a private fire service main designed under NFPA 24, a section of pipe is buried
in soil with a resistivity of 1,200 ohm-cm and contains dissimilar metals (steel and
brass). Which corrosion control method is required to mitigate galvanic corrosion
at the joint?
A. Install a dielectric union or insulating flange at the dissimilar metal connection. CORRECT
B. Apply a single coat of red oxide primer to the entire pipe exterior.
C. Increase the pipe wall thickness by one schedule to compensate for corrosion allowance.
D. Backfill with sand and compact to 95% density to exclude moisture.
RATIONALE: NFPA 24 requires dielectric insulation between dissimilar metals to break the
galvanic couple. Priming, wall thickness increase, and backfilling do not prevent galvanic current
flow; only electrical isolation stops the corrosion cell.
Q2 APPLY NFPA 24 HYDRAULIC AND DESIGN CRITERIA TO PRIVATE FIRE SERVICE MAINS
AND APPURTENANCES
A Texas insurance plan reviewer receives a fire main plan showing a 6-inch ductile
iron pipe with a 4-inch branch line feeding a hydrant. According to NFPA 24, what
is the minimum required size for a fire hydrant branch line?
A. 4 inches
B. 6 inches CORRECT
C. 2 inches
D. 8 inches
RATIONALE: NFPA 24 mandates a minimum 6-inch branch line for fire hydrants to ensure
adequate flow for firefighting. A 4-inch line is insufficient and would fail hydraulic and code
review. The other sizes are either too small or not required as minimums.
Page 2
,Q3 APPLY NFPA 24 HYDRAULIC AND DESIGN CRITERIA TO PRIVATE FIRE SERVICE MAINS
AND APPURTENANCES
During a hydrostatic test of a private fire service main, the contractor records a
pressure drop from 200 psi to 190 psi over two hours with no visible leaks. The
pipe is 8-inch ductile iron, 1,000 feet long. What is the most likely cause of the
pressure loss?
A. Air trapped in the line absorbing pressure. CORRECT
B. Thermal contraction of water due to temperature drop.
C. Minor leakage at the test cap gasket.
D. Pipe expansion under pressure.
RATIONALE: Trapped air compresses and dissolves, causing pressure fluctuations; NFPA 24
requires venting before testing. Thermal contraction would lower pressure but is less common in
short tests. Minor leaks would show visible water; pipe expansion would not cause a drop.
Q4 APPLY NFPA 24 HYDRAULIC AND DESIGN CRITERIA TO PRIVATE FIRE SERVICE MAINS
AND APPURTENANCES
Under TDI rules, which document must be submitted with a fire main plan to verify
that the water supply can meet the required fire flow for a new commercial
building?
A. A copy of the water district's most recent consumer confidence report.
B. A hydraulic calculation stamped by a Texas-licensed professional engineer. CORRECT
C. A letter from the local fire marshal stating the hydrant spacing is adequate.
D. A material certification for the pipe manufacturer.
RATIONALE: TDI requires a PE-stamped hydraulic calculation to demonstrate adequate flow and
pressure. Consumer confidence reports, fire marshal letters, and material certs do not prove
hydraulic adequacy. Only a stamped calculation satisfies the regulatory requirement.
Page 3
, Q5 APPLY NFPA 24 HYDRAULIC AND DESIGN CRITERIA TO PRIVATE FIRE SERVICE MAINS
AND APPURTENANCES
A private fire service main is installed in a region where the frost depth is 36
inches. What is the minimum cover required for the pipe if it is not protected
against freezing?
A. 12 inches below grade
B. 24 inches below grade
C. 36 inches below grade CORRECT
D. 48 inches below grade
RATIONALE: NFPA 24 requires burial below the frost line; if frost depth is 36 inches, minimum
cover is 36 inches. Less cover risks freezing; more is unnecessary unless local codes dictate.
The other depths do not meet the frost depth requirement.
Q6 APPLY NFPA 24 HYDRAULIC AND DESIGN CRITERIA TO PRIVATE FIRE SERVICE MAINS
AND APPURTENANCES
Which valve type is required at the connection between a private fire service main
and a public water main to allow isolation without interrupting public supply?
A. Post indicator valve (PIV)
B. Outside screw and yoke (OS&Y) gate valve CORRECT
C. Butterfly valve with tamper switch
D. Pressure reducing valve
RATIONALE: NFPA 24 specifies an OS&Y gate valve at the public supply connection to provide
visible indication and isolation. PIVs are used for system control but not typically at the public
main. Butterfly valves may be allowed but OS&Y is the standard. PRVs are for pressure control,
not isolation.
Page 4
AND ANSWERS VERIFIED AND WELL DETAILED ANSWERS PLUS
RATIONALES GUARANTEED PASS LATEST EXAM UPDATE
90 QUESTIONS
TABLE OF CONTENTS
# TOPIC
1 Apply NFPA 24 hydraulic and design criteria to private fire service mains and appurtenances
2 Evaluate Texas Department of Insurance statutory and rule-based requirements for fire protection system
plan review and approval
3 Diagnose common installation, testing, and maintenance deficiencies in private fire service mains and
recommend compliant corrections
4 TEXAS DEPARTMENT OF INSURANCE TFM10 NFPA 24 EXAM QUESTIONS AND ANSWERS
VERIFIED AND WELL DETAILED ANSWERS PLUS RATIONALES GUARANTEED PASS LATEST
EXAM UPDATE
5 Foundations of Fire Protection Engineering & Texas Insurance Code (TFM10 / NFPA 24)
6 Applied Fire Protection Engineering & Texas Insurance Code (TFM10 / NFPA 24)
7 Advanced Fire Protection Engineering & Texas Insurance Code (TFM10 / NFPA 24)
8 Fire Protection Engineering & Texas Insurance Code (TFM10 / NFPA 24) Review
ABSTRACT
This study document brings together 90 carefully worded exam questions drawn from TEXAS
DEPARTMENT OF INSURANCE TFM10 NFPA 24 EXAM QUESTIONS AND ANSWERS
VERIFIED AND WELL DETAILED ANSWERS PLUS RATIONALES GUARANTEED PASS LATEST
EXAM UPDATE, with the strongest emphasis placed on Apply NFPA 24 hydraulic and design
criteria to private fire service mains and appurtenances, Evaluate Texas Department of Insurance
statutory and rule-based requirements for fire protection system plan review and approval,
Diagnose common installation, testing and and maintenance deficiencies in private fire service
mains and recommend compliant corrections. Every item follows the wording style and level of
reasoning you meet in the real paper, and each one is paired with a clear rationale so the correct
choice is never a guess. Work through the set at your own pace, mark the questions that slow you
down, then come back to them until the reasoning feels automatic. Learners who revise this way
walk into the exam room recognising the pattern behind the questions instead of meeting them for
the first time. Keep going - steady, honest practice is what turns a difficult paper into a comfortable
pass.
Page 1
,Q1 APPLY NFPA 24 HYDRAULIC AND DESIGN CRITERIA TO PRIVATE FIRE SERVICE MAINS
AND APPURTENANCES
In a private fire service main designed under NFPA 24, a section of pipe is buried
in soil with a resistivity of 1,200 ohm-cm and contains dissimilar metals (steel and
brass). Which corrosion control method is required to mitigate galvanic corrosion
at the joint?
A. Install a dielectric union or insulating flange at the dissimilar metal connection. CORRECT
B. Apply a single coat of red oxide primer to the entire pipe exterior.
C. Increase the pipe wall thickness by one schedule to compensate for corrosion allowance.
D. Backfill with sand and compact to 95% density to exclude moisture.
RATIONALE: NFPA 24 requires dielectric insulation between dissimilar metals to break the
galvanic couple. Priming, wall thickness increase, and backfilling do not prevent galvanic current
flow; only electrical isolation stops the corrosion cell.
Q2 APPLY NFPA 24 HYDRAULIC AND DESIGN CRITERIA TO PRIVATE FIRE SERVICE MAINS
AND APPURTENANCES
A Texas insurance plan reviewer receives a fire main plan showing a 6-inch ductile
iron pipe with a 4-inch branch line feeding a hydrant. According to NFPA 24, what
is the minimum required size for a fire hydrant branch line?
A. 4 inches
B. 6 inches CORRECT
C. 2 inches
D. 8 inches
RATIONALE: NFPA 24 mandates a minimum 6-inch branch line for fire hydrants to ensure
adequate flow for firefighting. A 4-inch line is insufficient and would fail hydraulic and code
review. The other sizes are either too small or not required as minimums.
Page 2
,Q3 APPLY NFPA 24 HYDRAULIC AND DESIGN CRITERIA TO PRIVATE FIRE SERVICE MAINS
AND APPURTENANCES
During a hydrostatic test of a private fire service main, the contractor records a
pressure drop from 200 psi to 190 psi over two hours with no visible leaks. The
pipe is 8-inch ductile iron, 1,000 feet long. What is the most likely cause of the
pressure loss?
A. Air trapped in the line absorbing pressure. CORRECT
B. Thermal contraction of water due to temperature drop.
C. Minor leakage at the test cap gasket.
D. Pipe expansion under pressure.
RATIONALE: Trapped air compresses and dissolves, causing pressure fluctuations; NFPA 24
requires venting before testing. Thermal contraction would lower pressure but is less common in
short tests. Minor leaks would show visible water; pipe expansion would not cause a drop.
Q4 APPLY NFPA 24 HYDRAULIC AND DESIGN CRITERIA TO PRIVATE FIRE SERVICE MAINS
AND APPURTENANCES
Under TDI rules, which document must be submitted with a fire main plan to verify
that the water supply can meet the required fire flow for a new commercial
building?
A. A copy of the water district's most recent consumer confidence report.
B. A hydraulic calculation stamped by a Texas-licensed professional engineer. CORRECT
C. A letter from the local fire marshal stating the hydrant spacing is adequate.
D. A material certification for the pipe manufacturer.
RATIONALE: TDI requires a PE-stamped hydraulic calculation to demonstrate adequate flow and
pressure. Consumer confidence reports, fire marshal letters, and material certs do not prove
hydraulic adequacy. Only a stamped calculation satisfies the regulatory requirement.
Page 3
, Q5 APPLY NFPA 24 HYDRAULIC AND DESIGN CRITERIA TO PRIVATE FIRE SERVICE MAINS
AND APPURTENANCES
A private fire service main is installed in a region where the frost depth is 36
inches. What is the minimum cover required for the pipe if it is not protected
against freezing?
A. 12 inches below grade
B. 24 inches below grade
C. 36 inches below grade CORRECT
D. 48 inches below grade
RATIONALE: NFPA 24 requires burial below the frost line; if frost depth is 36 inches, minimum
cover is 36 inches. Less cover risks freezing; more is unnecessary unless local codes dictate.
The other depths do not meet the frost depth requirement.
Q6 APPLY NFPA 24 HYDRAULIC AND DESIGN CRITERIA TO PRIVATE FIRE SERVICE MAINS
AND APPURTENANCES
Which valve type is required at the connection between a private fire service main
and a public water main to allow isolation without interrupting public supply?
A. Post indicator valve (PIV)
B. Outside screw and yoke (OS&Y) gate valve CORRECT
C. Butterfly valve with tamper switch
D. Pressure reducing valve
RATIONALE: NFPA 24 specifies an OS&Y gate valve at the public supply connection to provide
visible indication and isolation. PIVs are used for system control but not typically at the public
main. Butterfly valves may be allowed but OS&Y is the standard. PRVs are for pressure control,
not isolation.
Page 4
