IFC Installation Practices and Procedures 2 — Questions and Answers
Question 1: Before installing a firestop system in a concrete floor penetration, what surface preparation step is most critical?
- Apply a primer coat to the concrete
- Remove all dust, debris, and contaminants from the opening (Correct answer)
- Wet the concrete to prevent moisture absorption
- Sand the edges of the opening smooth
Correct answer: Remove all dust, debris, and contaminants from the opening
Clean, contaminant-free surfaces are required for firestop materials to bond properly and achieve the listed system's fire-resistance rating.
Question 2: When a firestop system drawing calls for backing material, what is the primary function of the backer rod or mineral wool?
- To add structural reinforcement to the wall assembly
- To serve as the primary firestop barrier
- To provide a substrate and control depth for sealant application (Correct answer)
- To absorb moisture and prevent condensation
Correct answer: To provide a substrate and control depth for sealant application
Backing material controls the depth of sealant application and provides the required substrate so the sealant performs as tested.
Question 3: A firestop sleeve installed around a plastic pipe in a fire-rated wall must be secured according to the listing. Which fastening method is most commonly specified?
- Adhesive bonding only
- Mechanical anchors through the flanges into the wall substrate (Correct answer)
- Wire ties to adjacent conduit
- Gravity seating without fasteners
Correct answer: Mechanical anchors through the flanges into the wall substrate
Mechanical anchoring through the sleeve flanges into the wall substrate ensures the intumescent element is held in position to close around a melting pipe during fire.
Question 4: What does 'minimum annular space' refer to in a firestop system listing?
- The smallest permitted gap between two penetrating items in the same opening
- The minimum gap between the penetrating item and the edge of the opening (Correct answer)
- The thinnest allowable sealant bead width
- The shortest acceptable length of firestop material
Correct answer: The minimum gap between the penetrating item and the edge of the opening
Minimum annular space is the smallest allowable gap between the penetrating item and the opening perimeter, which must be maintained for the system to perform as tested.
Question 5: Which scenario would INVALIDATE a listed firestop system for a cable bundle penetration?
- Installing the sealant in two passes rather than one
- Using a cable bundle diameter smaller than the maximum listed
- Adding cables to the bundle after firestop installation without re-firestopping (Correct answer)
- Allowing the sealant to cure for 24 hours before occupancy
Correct answer: Adding cables to the bundle after firestop installation without re-firestopping
Adding cables after installation changes the fill percentage and annular space, invalidating the original listed system and requiring re-firestopping.
Question 6: When installing a firestop pillow in a cable tray penetration, how should the pillows be oriented relative to each other?
- Stacked vertically in a single column
- Placed in a staggered brick-lay pattern to eliminate through-paths (Correct answer)
- Laid flat in a single layer only
- Positioned only at the perimeter of the tray
Correct answer: Placed in a staggered brick-lay pattern to eliminate through-paths
A staggered brick-lay pattern eliminates straight-through paths that could allow flame and smoke passage if one pillow shifts.
Question 7: A rated floor-ceiling assembly requires a firestop system for a steel pipe. The installer notices the pipe is insulated. Which action is correct?
- Remove the insulation within the firestop zone and re-insulate after
- Select a firestop system specifically listed for an insulated steel pipe (Correct answer)
- Use the bare steel pipe listing since insulation does not affect fire performance
- Apply firestop sealant over the insulation without any listing requirement
Correct answer: Select a firestop system specifically listed for an insulated steel pipe
An insulated pipe changes the penetration configuration, so a listing that specifically covers insulated pipe in that assembly must be used.
IFC Installation Practices and Procedures 2
Before installing a firestop system in a concrete floor penetration, what surface preparation step is most critical?