IFC Installation Practices and Procedures 3 — Questions and Answers
Question 1: During a firestop installation, the installer finds the wall opening is 20% larger than specified in the listing. What is the correct course of action?
- Fill the extra space with additional sealant and proceed
- Stop work and consult a firestop engineering judgment or alternate listing (Correct answer)
- Pack the extra space with drywall pieces and continue
- Proceed if the excess is less than 25%
Correct answer: Stop work and consult a firestop engineering judgment or alternate listing
An opening larger than the listed dimension is outside the scope of the tested system and requires an engineering judgment or a listing that covers the actual opening size.
Question 2: What is the correct procedure when installing firestop sealant in a joint that will experience movement?
- Apply sealant before any movement is expected and allow it to fully cure
- Select a sealant listed for the anticipated movement capability of that joint (Correct answer)
- Apply extra thickness of sealant to compensate for movement
- Use rigid materials to prevent joint movement
Correct answer: Select a sealant listed for the anticipated movement capability of that joint
Dynamic joints require firestop materials specifically tested and listed for the expected movement range to maintain integrity under both normal and fire conditions.
Question 3: How is the 'F-rating' of a through-penetration firestop system defined?
- The time a firestop system prevents flame passage through an opening (Correct answer)
- The fire-resistance rating of the surrounding construction
- The number of fire cycles the system has been tested for
- The temperature at which the firestop material activates
Correct answer: The time a firestop system prevents flame passage through an opening
The F-rating is the time period in hours during which a firestop system prevents the passage of flame through the tested opening.
Question 4: When installing a fire-rated expansion joint cover, the installer must verify which critical dimension matches the listing?
- The cover plate color and finish
- The joint width at time of installation relative to the listed range (Correct answer)
- The height of the cover above the floor
- The number of fasteners used per linear foot
Correct answer: The joint width at time of installation relative to the listed range
The joint width at time of installation must fall within the range tested in the listing, as it affects the system's ability to accommodate movement while maintaining fire resistance.
Question 5: Which tool is essential for verifying that caulk sealant depth meets listing requirements during installation?
- A calibrated infrared thermometer
- A depth gauge or wet film thickness comb (Correct answer)
- A torque wrench for fastener tension
- A hardness tester for cured sealant
Correct answer: A depth gauge or wet film thickness comb
A depth gauge or wet film thickness comb verifies that sealant is applied at the depth specified in the listing before it cures.
Question 6: A firestop system listing specifies mineral wool packing to a depth of 4 inches before sealant application. An installer uses 2-inch packing instead. This deviation is:
- Acceptable if more sealant is applied to compensate
- A minor variation allowed within normal construction tolerances
- A violation of the listing that invalidates the system (Correct answer)
- Permitted if the wall is thicker than standard
Correct answer: A violation of the listing that invalidates the system
Packing depth is a tested parameter; using less than specified changes thermal and structural performance, invalidating the listed system.
Question 7: After completing firestop installation in a plumbing rough-in, the installer must do what before the work area is enclosed?
- Paint the sealant to match the surrounding wall color
- Ensure the installation is inspected and documented before concealment (Correct answer)
- Apply a second firestop product layer for redundancy
- Notify only the general contractor, not the AHJ
Correct answer: Ensure the installation is inspected and documented before concealment
Firestop work must be inspected and documented before it is concealed so the AHJ can verify compliance with the listing and applicable codes.
IFC Installation Practices and Procedures 3
During a firestop installation, the installer finds the wall opening is 20% larger than specified in the listing.
What is the correct course of action?