CFPS Passive Fire Protection 3 — Questions and Answers
Question 1: In a through-penetration firestop system, the 'F-rating' represents:
- The time the system prevents passage of flame through the firestopped opening (Correct answer)
- The time the unexposed-side temperature remains below 325°F above ambient
- The flexibility classification of the firestop sealant material
- The fire hazard index of the penetrating item
Correct answer: The time the system prevents passage of flame through the firestopped opening
The F-rating is the time in hours that a firestop system prevents passage of flame through a penetration, as measured in UL 1479 or ASTM E814 tests.
Question 2: Which UL standard is the primary U.S. test standard for through-penetration firestop systems?
- UL 263
- UL 1479 (Correct answer)
- UL 2079
- UL 723
Correct answer: UL 1479
UL 1479 (Fire Tests of Through-Penetration Firestops) is the primary U.S. listing standard for evaluating through-penetration firestop assemblies.
Question 3: The 'T-rating' in a through-penetration firestop system measures:
- Tensile strength retention of the firestop material after fire exposure
- The time that the temperature on the unexposed face of the assembly and the penetrating item remains below 325°F above ambient (Correct answer)
- Thermal conductivity of the annular space fill material
- The time before the penetrating item itself ignites
Correct answer: The time that the temperature on the unexposed face of the assembly and the penetrating item remains below 325°F above ambient
The T-rating measures the time until the unexposed-side temperature (on the assembly or penetrating item) exceeds 325°F above ambient, limiting heat transmission.
Question 4: An intumescent firestop sealant provides protection primarily by:
- Absorbing heat through an endothermic chemical reaction that consumes energy
- Expanding dramatically when exposed to heat to fill the void left by a burning or melting penetrating item (Correct answer)
- Releasing a suppressant gas when a threshold temperature is reached
- Chemically bonding to metallic pipe surfaces to form an airtight seal
Correct answer: Expanding dramatically when exposed to heat to fill the void left by a burning or melting penetrating item
Intumescent materials expand (intumesce) when exposed to heat, filling the annular space or void created as combustible pipes burn away, maintaining the rated assembly.
Question 5: What is the 'annular space' in the context of a through-penetration firestop system?
- The gap between the penetrating item and the edge of the opening cut through the fire-rated assembly (Correct answer)
- The ring of intumescent wrap installed around a plastic pipe
- The air gap maintained inside a fire-rated cavity wall
- The clearance between a fire door and its frame per NFPA 80
Correct answer: The gap between the penetrating item and the edge of the opening cut through the fire-rated assembly
The annular space is the void between the outside of the penetrating item (pipe, cable, duct) and the edge of the hole in the rated assembly that must be firestopped.
Question 6: A 'membrane penetration' in fire-rated construction differs from a through-penetration because it:
- Involves a penetrating item that passes completely through both membranes of a rated wall
- Passes through only one membrane (one side) of a fire-rated assembly, not extending through the full assembly thickness (Correct answer)
- Uses a membrane-type firestop product rather than a sealant
- Requires no firestop protection because it does not breach both membranes
Correct answer: Passes through only one membrane (one side) of a fire-rated assembly, not extending through the full assembly thickness
A membrane penetration breaches only one side of a rated assembly (e.g., an electrical box in one face of a rated wall), and also requires listed protection per IBC Section 714.
Question 7: Per IBC Section 714, the F-rating of a through-penetration firestop system must be at minimum:
- 30 minutes regardless of the assembly rating
- Equal to the fire-resistance rating of the assembly being penetrated (Correct answer)
- One-half the fire-resistance rating of the penetrated assembly
- 2 hours for all assemblies in high-rise buildings
Correct answer: Equal to the fire-resistance rating of the assembly being penetrated
IBC Section 714.4.1 requires that the F-rating of the firestop system be not less than the required fire-resistance rating of the penetrated assembly.
CFPS Passive Fire Protection 3
In a through-penetration firestop system, the 'F-rating' represents: