Life safety dampers are an important part of fire and smoke protection in commercial buildings. Much like smoke detectors and fire sprinklers, they need to be periodically tested, per the International Fire Code, to ensure they will perform as designed, if needed. Unfortunately, for reasons including poor accessibility, owner unwillingness to disrupt business operations, misconceptions of damper importance, and lack of a local mandate, dampers are often not tested as required by the National Fire Protection Association (NFPA).
This article provides an overview of life safety dampers and the practical considerations concerning various types of testing.
Types of Life Safety Dampers
There are three types of life safety dampers: fire dampers, smoke dampers, and combination fire/smoke dampers and corridor dampers.
A fire damper is a curtain or multi-blade damper held open with a fusible link. During a fire event, the link melts and the damper closes.
A smoke damper is a multi-blade damper that operates with an actuator and is controlled by a smoke detector or a fire-alarm panel relay.
A combination fire/smoke damper is a single or multi-blade damper that operates with an actuator and has an electronic thermal switch that disconnects power to the actuator. The actuator closes the damper as temperature increases during a fire event.
Testing and Maintenance
Testing and maintenance requirements are provided in Chapter 19 of NFPA 80 for fire dampers and Chapter 7 of NFPA 105 for motorized smoke dampers and combination fire/smoke dampers.
Dampers that incorporate a fusible link need an operational test to be performed after installation (NFPA 80, Section 19.3). This ensures the damper is installed properly and there are no interferences with damper operation. The most common issue associated with damper installation is a screw in the blade tracks stopping the blades from closing.
With a motorized damper or a combination fire/smoke damper, an operational test is conducted after the HVAC system is balanced (NFPA 105, 7.4). This is to verify the damper functions properly under airflow. This test can be incorporated into acceptance testing.
Testing needs to be performed by qualified personnel with knowledge and understanding of how dampers operate as well as the system in which the dampers are installed. This ensures proper operational testing and helps prevent injury to the person doing the testing and/or damage to the system (NFPA 80, 19.4.1).
Acceptance Testing
Tests involving dampers with fusible links require the link to be removed so the blades can close. After it is confirmed to have closed all the way, the damper is opened and the link is replaced (NFPA 80, 19.4.4.1).
During acceptance testing, if a damper/actuator is equipped with position-indicating switches, the signal from the switches to the indicating device must demonstrate the proper damper-closed or damper-open position at the control panel.
Periodic Testing
After initial installation and testing to verify proper operation, a life safety damper is tested again one year later or during commissioning of the building (NFPA 80, 19.5, and NFPA 105, 7.6.2). The damper should be re-inspected and tested every four years, unless it is installed in a hospital, in which case is every six years.
All the life safety dampers in the facility listed above require documentation indicating, at a minimum, the location of the damper, date of the inspection, name of the inspector, and any deficiencies discovered. The documentation has to be kept a minimum of three cycles. (NFPA 80, 19.5.3.1, and NFPA 105, 7.7.6)
Damper Selection for Ease of Maintenance
Determining which dampers are best for a particular building type and occupancy is difficult. It is good practice to specify the specific type of damper required at each location. Specifying only “fire damper” can cost the building owner thousands of dollars a year in maintenance and testing.
Lowest Damper Cost
A curtain damper is the lowest cost damper to buy and install. Testing and maintenance, however, require access through the ceiling and also into the duct. This type of service exposes occupants to dust and potential bio-organisms. Removing the fusible link and cycling the damper can be particularly difficult.
Multi-Blade Fire Dampers
A static or dynamic multiple-blade fire damper is supplied with a fuse link without an actuator or with an actuator and electronic thermal switch. These units are just one step below a motorized combination fire/smoke damper.
While their construction is almost the same, they use a spring and fuse link as opposed to an actuator that’s used in a combination fire smoke damper. This is utilized to close the damper when the fuse link melts. These dampers cost almost the same as motorized dampers with the same access requirements and interruptions to building occupants.
Motorized Smoke and Combination Fire/Smoke Dampers
Though motorized smoke and combination fire/smoke dampers may cost more to purchase, installation is the same as any other fire damper. The added benefit is the cost of inspection and maintenance. Testing can be as easy as pushing a button on a panel or programming a fire-alarm panel where testing is done automatically.
Best Dampers and Options to Reduce Maintenance Cost
Dampers that utilize fuse links, like curtain fire dampers or multi-blade fire dampers, are affordable solutions that are very good at stopping a fire from spreading. However, accessing the dampers is still an issue because it exposes occupants to dust and potential bio-organisms. There are also difficulties removing the fusible link and cycling the damper. Dampers with motors (actuators) are user-friendly and can be tested remotely or by an addressable system. This reduces the building owner’s inspection and maintenance costs by making the damper testing more routine.
Damper Test Switches
Regardless of the fire-alarm panel or building management system, all smoke dampers, combination fire/smoke dampers, or corridor dampers should include a damper test switch (DTS). Mounted directly to a damper, the DTS allows the damper to be tested with a simple push of a button or flip of a switch. A DTS eliminates time spent removing the fusible link, cycling the damper by hand, and replacing the link. Access through the ceiling is required.
Master Control Panel
A master control panel (MCP) requires blade-indicating switches. With factory-installed blade switches, an MCP can be installed remotely and wired to a damper. This allows the MCP to be located in an area below ceiling tiles and requires only the push of a button or flip of a switch for a damper to be tested.
Addressable Damper Controller
The best option is a motorized combination fire/smoke damper with blade indication. Installing such a damper requires no extra wiring, and the damper can be made addressable to a fire alarm panel. When it’s time for the damper to be tested, the panel can be programmed ahead of time so the damper cycles on its own. Only if the damper does not completely close and reopen will there be reason to access the damper. Another benefit is the damper can be monitored full-time through the fire alarm panel, so if something happens to the damper, the fire alarm system will be alerted and can notify the proper authority.
Conclusion/Summary
NFPA now allows.
Choices:
1. Manual testing;
2. Remote test station; and
3. Addressable damper controller.
Dampers that utilize fuse links, like curtain fire dampers or multi-blade fire dampers, are low-cost solutions that are good at stopping fire from spreading; however, they still must be visually inspected. Challenges also remain in accessing the dampers and exposing occupants to dust and potential bio-organisms as well as difficulties removing the fusible link and cycling the damper. Dampers with motors (actuators) are user-friendly and can be tested remotely or by an addressable system. This reduces the building owner’s inspection and maintenance cost by making the damper testing more routine.
