HVAC Systems & Airflow Control Flashcards

Which test is used to verify that a smoke damper actuator will close the damper within the required time after receiving a control signal?

Answer: Operational test per NFPA 105

NFPA 105, Standard for Smoke Door Assemblies and Other Opening Protectives, includes operational test requirements that verify smoke damper response time upon receiving a control signal.

A fire damper in a curtain-type (multi-blade) configuration differs from a single-blade design primarily in that:

Answer: Multiple interlocking blades fold into a pocket when open and drop closed as a curtain when triggered

Curtain-type fire dampers use multiple interlocking blades stored in a side pocket when open; upon fusible link release, the blades deploy across the duct opening like a falling curtain.

What is the significance of the 'E' suffix in a smoke damper's leakage classification (e.g., Class II E)?

Answer: The damper is tested for leakage at elevated temperature per UL 555S

The 'E' suffix in UL 555S leakage classifications indicates the damper has been tested and rated for leakage performance at elevated temperatures (250°F), verifying it maintains containment in hot smoke conditions.

When sizing a fire damper for installation in a duct, which factor determines the required damper size?

Answer: The outside dimensions of the duct or the rough opening in the rated assembly

Fire damper size is determined by the duct outside dimensions or the rough opening in the rated wall/floor assembly, ensuring the damper sleeve fits properly and seals the penetration.

In a dedicated smoke exhaust system, smoke dampers on floors not involved in a fire are typically:

Answer: Closed to prevent smoke from spreading to those floors via the exhaust shaft

In a dedicated exhaust smoke control system, dampers on uninvolved floors are closed so the exhaust fan draws smoke only from the fire floor, maximizing extraction efficiency and preventing spread.

What must be provided at a fire damper installation location to allow for inspection and maintenance per IBC and NFPA 90A?

Answer: An access door or panel of sufficient size to inspect and reset the damper

Both IBC and NFPA 90A require an access door or panel adjacent to each fire damper so inspectors and technicians can visually inspect the damper, replace fusible links, and reset the assembly.

Which scenario would cause a fire damper fusible link to be replaced without restoring the damper to full operation?

Answer: The link is replaced with a higher-rated temperature link to reduce nuisance trips

Substituting a higher-rated fusible link than specified in the listing changes the product's listing compliance; the damper would then fail to respond at the correct temperature, violating its UL listing.