Firestop Systems and Materials Flashcards

Which organization publishes the 'System Catalog' known as the UL Fire Resistance Directory that installers reference for listed firestop systems?

Answer: UL (Underwriters Laboratories)

UL publishes the Fire Resistance Directory (and its online equivalent, UL Product iQ) which catalogs all tested and listed firestop systems under UL 1479.

A firestop sealant manufacturer's data sheet lists a maximum joint width for a wall joint application. What happens if the actual field joint exceeds that maximum?

Answer: The listing no longer applies; a wider-joint listed system or EJ is required

Each listed system has maximum dimensions; exceeding any dimension means the installation falls outside the tested parameters and the listing is invalid without an EJ or alternate listed system.

What role does 'depth of fill' play in a firestop sealant application per the listing requirements?

Answer: It is critical because the tested minimum depth must be maintained to achieve the rated performance

The minimum depth of fill is a critical parameter in every sealant-based listing; insufficient depth reduces fire-resistance performance and invalidates the rated system.

Which penetrating item classification requires special concern for 'melt-out' in a fire scenario?

Answer: Thermoplastic (PVC/CPVC) piping

Thermoplastic pipes (PVC, CPVC) melt and burn away in a fire, leaving a void that must be actively sealed by an intumescent or other reactive material during the fire event.

When installing a firestop system in a horizontal floor/ceiling assembly, what is the significance of identifying whether the assembly is a 'floor' or 'floor/ceiling' assembly?

Answer: Different UL system series apply, and the presence of a ceiling can change the required product type and configuration

UL distinguishes floor assemblies (C-AJ) from floor/ceiling assemblies (L-series and others); the ceiling membrane affects heat exposure and different listed systems are required for each configuration.

A firestop wrap strip is typically applied around which type of penetrating item prior to installation?

Answer: Combustible plastic pipe

Wrap strips are intumescent products that are wrapped around combustible plastic pipes before they are installed through the barrier; heat causes the strip to expand and close the void left by the melting pipe.

Under NFPA 101, what term describes the fire-rated separations required between floors of a multi-story building that must include compliant firestop systems at penetrations?

Answer: Floor/ceiling assemblies serving as fire barriers

NFPA 101 requires floor/ceiling assemblies acting as fire barriers between stories, and all penetrations through these assemblies must be protected with listed firestop systems.