Integration: Building automation and fire alarms
Creating a code-compliant integrated system
When considering system integration, the ability of the BAS to control a smoke control system operation falls under the auspice of the jurisdiction’s building code, often based on the model building codes. The IBC has been adopted by a large portion of the United States and is used in this article as an example. IBC Section 909 covers smoke control systems, the procedures for determining system parameters, the acceptable methods that may be used to accomplish smoke control, and the requirements to document the system’s actual performance. It recognizes that the smoke control system is a life safety system and must maintain the same high level of reliability required for any type of fire protection or fire alarm system.
Section 909 requires smoke control systems to be initiated by sprinkler system or smoke detection system operation, depending on the type of system being designed. It also requires systems providing control input or output to the mechanical smoke control systems to comply with Section 907 (Fire Alarm and Detection Systems) and NFPA 72: National Fire Alarm and Signaling Code, and states that such systems must be equipped with a control unit that complies with UL 864 and has to be listed as smoke control equipment.
UL 864 requirements cover control units and accessories that are used to meet the requirements of many NFPA standards, including NFPA 72, NFPA 92A: Standard for Smoke-Control Systems, and NFPA 92B: Guide for Smoke Management Systems in Malls, Atria, and Large Areas. Each system is tested by UL, which then lists the complying equipment under the “UUKL” designation in the product directory. The fire alarm and building automation systems must meet these requirements and be listed in order to control a smoke control system and be configured as an integrated system.
Inspection and testing
Integrated systems require enough time to test and to verify that the system interoperability is functioning properly. It is important that the engineer as well as the installing contractor and the equipment vendors understand the impact of these requirements on providing an approved and code compliant installation.
Due to the complexity of these systems and the required integration, testing must confirm that the functions and sequences work correctly under both automatic and manual modes.
The inspection and testing of integrated systems is usually exasperating and time-consuming, and often requires multiple rounds of retesting before all the deficiencies are corrected. This is often caused due to all of these different systems being completed late in the schedule and not enough time to “get the kinks out” prior to final testing. Anything that can expedite the commissioning process is beneficial to the overall project.
One of the advantages of using the BAS as an integrated part of the smoke control system is the system’s ability to modify operating conditions to accommodate actual ambient conditions through the use of VFDs. The design of smoke control systems is based on many variable conditions, including temperature, wind conditions, and the quality or “tightness” of the construction. These conditions tend to make testing and adjusting of the smoke control system difficult at best.
Integrating BAS can help minimize test stress by adjusting the fan speed of individual fans through programming. In a situation of excessive stair pressurization, the individual fan can be adjusted to limit its airflow to the stair, resulting in a lower level of pressure affecting door opening forces. Similarly, for individual zone smoke control system performance, the fan speed can be adjusted on a zone-by-zone basis, based on the fire alarm signal received by the BAS.
The downside to this operation is that the BAS controls are typically located remotely to the fire alarm control panel and the firefighters’ smoke control panel, both of which normally reside in a fire command room. BAS controls and system components are usually located for the convenience of the building’s staff and HVAC equipment. Under test conditions, additional personnel may be required to monitor the BAS controls to make any required modifications.
While modifying fan output for each smoke zone condition is a more expedient method to obtain approval, it also provides future opportunities to inappropriately change the settings, possibly making the system ineffective. Care must be taken to limit access to this programming and provide logging procedures to document when and why changes are made.
After all the work is done by the engineers, contractors, inspectors, and the AHJ, the integrated system operation is approved and the owner receives its total cost of ownership and, eventually, its final certificate of occupancy. However, the project is not over. It is critical that the owner receives and carefully stores all record documents related to the integrated system. As a building ages, things change and systems are modified. When changes occur, the contractors making the changes can use the documentation to maintain the interoperability of the integrated system as well as revise the drawings to reflect changes made. In addition, the modified systems should be retested to confirm their revised performance. Documentation of the testing should be incorporated with the existing record documents.
Integrating fire protection and fire alarm systems with BAS can be cost-effective and provide a more efficient operation. It is imperative that the design and installation is well planned and coordinated, and that the system is properly maintained over its lifetime.
Jon Kapis is the operations manager in the Seattle office of The RJA Group, and has more than 32 years of experience in fire alarm and building systems integration. Rick Lewis is a senior consultant in the San Francisco office of The RJA Group, with more than 28 years of experience in the fire and security alarm industry. Craig Studer is vice president in the Chicago office of The RJA Group, with more than 30 years of consulting experience in building commissioning and system integration.