Henderson Engineers — Ensuring Damper Performance by Mark Chrisman

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ENSURING DAMPER PERFORMANCE CO M P R E H E NSIVE IN SP E C TIO N , TESTI NG AND MAI NTENANCE OF DAMP E RS IS E SS EN T I AL FO R SA F ETY A N D SYSTEM PERFORMANCE. Authored by: Mark Chrisman | June 4, 2018 Dampers are crucial to prevent the spread of fire and smoke in institutional and commercial facilities, so it is critical that they are designed, installed, and maintained according to applicable building, fire, and life safety codes.

The challenge for maintenance and engineering managers is to understand the gamut of issues related to damper installation and performance, including inspection, testing, and maintenance. Beyond these issues, managers need to be familiar with regulatory and standards compliance related to NFPA 80: Standard for Fire Doors and Other Opening Protectives, NFPA 105: Standard for Smoke Door Assemblies and Other Opening Protectives, NFPA 72: National Fire Alarm Code, and manufacturer requirements.

DOWNLOW ON DAMPERS Most multi-story facility HVAC systems generally include fire dampers, smoke dampers, or combination fire/smoke dampers, which serve a dual function against both threats. There are two main types of fire dampers: dynamic and static.

Dynamic fire dampers are UL tested to close against system air pressure and velocity. Static fire dampers also are UL tested but not listed to close against system air pressure and velocity.

Ceiling radiation dampers are used in fire-rated floor-ceiling or roof-ceiling assemblies. Smoke dampers are UL tested to restrict the movement of smoke. As the name indicates, combination fire/smoke dampers can perform the functions of both a fire damper and a smoke damper.

In a fire damper, the fusible link — a heat-detection device — controls the operation of the damper curtain blades. The fusible link opens in response to heat and activates the damper components, effectively preventing the spread of fire and the movement of air. While static fire dampers rely on gravity to close the curtain blades, dynamic fire dampers use a spring to close them. In cases where a static fire damper is located horizontally, a closure spring pulls the curtain blades closed. Smoke dampers typically are activated by a duct detector or spot-type smoke detector that senses smoke.

ENSURING DAMPER PERFORMANCE

KEEPING DAMPERS WORKING Properly maintaining dampers is imperative to its successful operation in the event of an emergency.

Regular maintenance for fire, smoke, and combination fire/smoke dampers must include these procedures: ▪▪ Verify proper access to test and maintain the damper.

▪▪ Check the actuator and tighten the linkage if required.

▪▪ Clean the damper blades as needed.

▪▪ Consult manufacturer as needed.

While new damper installations require clear and unobstructed access under NFPA 80 or NFPA 105, it is just as important to make sure technicians have access to existing dampers in order to perform inspection, testing, and maintenance. During routine maintenance, technicians also must make sure all exposed and moving parts are dry-lubricated as directed by the manufacturer.

If any change in airflow or noise occurs in the duct system — building occupants often notice such changes first — technicians need to inspect any fire and smoke dampers located in the system immediately and repair inoperable dampers as soon as possible. They also should subsequently test any dampers that had been repaired previously to verify proper operation, with documentation included.

HOW TO PROPERLY INSPECT AND TEST FIRE DAMPERS Technicians should visually inspect fire dampers in accordance with the testing schedule outlined by NFPA 80 unless the facility or local authority having jurisdiction (AHJ) has a policy that requires more frequent activity. Unlike testing, it is not necessary to inform occupants, owners, or other agencies when executing a visual inspection unless the situation requires further testing or repairs.

To perform a successful visual inspection, technicians need to ensure the line of sight is unobstructed.

Because the damper is designed to close automatically, they must make sure it is not blocked and that any object that will affect the operation of the frame is not penetrating it. They also need to confirm that the fusible link has not been painted or damaged because this will prevent the damper from engaging in the event of an emergency.

Visual inspections of smoke dampers as outlined in NFPA 105 are similar to the process for fire dampers.

One difference is that a smoke damper generally has an associated smoke or duct detector for activation.

NFPA 72 requires a semi-annual visual inspection of the spot-type smoke detector in addition to the visual inspection requirements outlined in NFPA 105.

ENSURING DAMPER PERFORMANCE Technicians should visually inspect combination fire/smoke dampers based on the aforementioned requirements for fire dampers and smoke dampers.

TESTING, TESTING Technicians need to test and inspect fire dampers one year after installation and every four years after that, except in hospitals, in which the frequency is every six years, according to NFPA 80. To begin the process, managers need to confirm that the technician performing the test is wearing the appropriate personal protective equipment (PPE), that all safety requirements have been provided, and that the appropriate parties have been notified that testing will occur. These parties could include the property manager, the fire alarm monitoring station or sub-contractor, the local AHJ, department directors, and building occupants that might be affected by the testing.

If a fusible link is present, the inspector should remove it prior to beginning testing. When dynamic dampers are present, testing in normal HVAC operation with air flow is the only way to prove its operation in the case of an actual event. Static dampers do not require airflow during operational testing. Successful operation during the test will verify there is no interference due to rust or damaged blades.

NFPA 105 provides requirements for smoke damper testing. It requires testing and inspection of the damper one year after installation and every four years after that, except in hospitals, in which the frequency is every six years.

As indicated above, managers need to verify that the appropriate safety measures and PPE are in use and that required parties have been notified before testing begins. As with testing dynamic fire dampers, testing a smoke damper should be done under normal airflow conditions to confirm no impediment to operation exists due to rust or damaged blades.

Besides the damper test required by NFPA 105, NFPA 72 requires an annual test of the spot-type smoke detector or duct detector that activates the smoke damper. It often is beneficial to perform these two tests at the same time, with both tests being documented in the proper NFPA 72/NFPA 105 documentation.with any questions.

GET IT IN WRITING NFPA 80 and NFPA 105 require that workers document all inspections and testing. It is important to be specific in documenting damper testing for AHJs, as well as for regulatory bodies that might review the testing for compliance.

Codes require the following information be logged after damper testing: location of the damper; date of inspection; inspector name; deficiencies discovered with repair information; and additional notes. While not required, it might be beneficial to the facility to have plans indicating the locations of dampers, the types of dampers, and other relevant information, such as an associated duct or spot-type smoke detector identifier for the fire alarm system.

By becoming familiar with the applicable codes and requirements, facility staff will be able to answer questions and ensure building safety. This information also prepares them to work effectively with the AHJ. Whether the design responsibility is in house or provided by a subconsultant, managers who understand fire and smoke dampers will be able enhance the performance of the systems and their organizations.

MARK CHRISMAN PE Mark Chrisman is an associate vice president, director of code consulting, and healthcare practice co-director at Henderson Engineers. He works primarily in critical spaces with life safety systems and provides code and life safety consulting, fire modeling, fire suppression, and fire alarm design services for a variety of healthcare, clinical, and office buildings nationwide.