FPE FPE Passive Fire Protection & Structural Fire Resistance 2 — Questions and Answers
Question 1: What is the critical steel temperature commonly used in US fire resistance design below which structural steel retains adequate load-bearing capacity?
- 300°F (149°C)
- 700°F (371°C)
- 1000°F (538°C) (Correct answer)
- 1500°F (816°C)
Correct answer: 1000°F (538°C)
1000°F (538°C) is the conventional US threshold below which structural steel is assumed to retain sufficient strength for the applied loads in fire resistance calculations.
Question 2: Which fire protection material is sprayed directly onto steel structural members to provide thermal insulation and achieve a fire resistance rating?
- Gypsum board sheathing
- Spray-applied fire resistive material (SFRM) (Correct answer)
- Mineral fiber batt insulation
- Cementitious floor underlayment
Correct answer: Spray-applied fire resistive material (SFRM)
SFRM (spray-applied fire resistive material), commonly called spray fireproofing, is applied to steel to achieve required fire resistance ratings and is governed by UL listings and AISC standards.
Question 3: A smoke barrier in a healthcare occupancy under NFPA 101 is required to have a minimum fire resistance rating of:
- No rating required, only smoke-tight construction
- 30 minutes
- 1 hour (Correct answer)
- 2 hours
Correct answer: 1 hour
NFPA 101 requires smoke barriers in healthcare occupancies to have a 1-hour fire resistance rating to support defend-in-place evacuation strategies.
Question 4: What does the 'W/D ratio' represent in determining the required SFRM thickness for structural steel?
- Width-to-depth ratio of the beam cross-section
- Weight per linear foot divided by heated perimeter (section factor) of the steel member (Correct answer)
- Wall thickness divided by door opening width
- Water-to-dry-mix ratio for fireproofing application
Correct answer: Weight per linear foot divided by heated perimeter (section factor) of the steel member
The W/D ratio (weight per foot divided by heated perimeter) is the section factor used with UL listings to determine the minimum SFRM thickness needed for a given fire resistance rating.
Question 5: Which IBC occupancy classification typically requires the highest level of fire-resistive construction (Type IA)?
- Single-family residential under 3 stories
- High-rise buildings over 75 feet in height (Correct answer)
- Small retail stores under 5,000 sq ft
- Open parking garages under 8 stories
Correct answer: High-rise buildings over 75 feet in height
High-rise buildings (over 75 ft) are required by IBC to use the most fire-resistive Type IA construction to address the challenges of occupant egress and firefighting operations.
Question 6: What is the purpose of a 'draft stop' in concealed combustible attic or crawl space construction?
- To direct sprinkler discharge patterns
- To subdivide concealed spaces to limit the spread of fire within them (Correct answer)
- To prevent HVAC air leakage into occupied spaces
- To support roof loads during fire exposure
Correct answer: To subdivide concealed spaces to limit the spread of fire within them
Draft stops subdivide concealed combustible spaces (attics, ceiling plenums) to limit how far fire can travel within them before reaching structural elements.
FPE FPE Passive Fire Protection & Structural Fire Resistance 2
What is the critical steel temperature commonly used in US fire resistance design below which structural steel retains adequate load-bearing capacity?