Integrating fire protection in building systems

Large-scale building systems integration, such as mass notification systems and video image smoke detectors, are aiming to cut costs and decrease energy usage as well as improve communications during emergency situations.

08/30/2011


For decades, there have been demonstration projects and product developments aimed at advancing the integration of building systems. Large corporations have promoted the concepts of “smart buildings” that exhibit enhanced functionality, energy efficiency, and reduced operating expense as incentives to invest in such technologies. Today, sustainability is a global objective driven by dwindling resources and escalating energy costs, but large-scale building integration is still the subject of demonstration projects. This article is intended to highlight several areas where building systems are being integrated and, hopefully, stimulate ideas for additional opportunities.

Prior to the emergence of digital controls and low-cost computers, building systems operated independently and integration was problematic. Where system components served multiple purposes, controls were arranged to work in parallel with priority given to critical functions, or the components were duplicated. An example is where HVAC components were used both for normal environmental air and for smoke management in the case of a fire. Providing separate smoke control fans was a significant expense.

In 1971, Honeywell introduced its Alpha 3000 control panel, which integrated fire alarm and HVAC controls, allowing for advanced smoke management arrangements such as zoned smoke control. The Alpha 3000 was attractive to building owners because the fire alarm and HVAC systems were accessed by a common operator console through a graphical user interface (GUI), which was futuristic for the time.

Building engineering staff was unfamiliar with GUIs, and control errors were common. It was reported that attempts to make routine adjustments, such as to temperature or airflow settings, could inadvertently result in disabling all the smoke detectors on a floor. Operator errors or component problems that caused the HVAC control to go down also took the building fire alarm system out of service. This led to a series of changes to NFPA 72: National Fire Alarm Code to require duplicate central processing units (CPUs) and operator access segregation that eventually made the integrated system impractical.

Intercommunication protocols

The ability to exchange information through common communication protocols is important for successful systems integration. As building systems converted from analog to digital controls, proprietary communication protocols were implemented to link the system components. When a component from a different manufacturer was added, that manufacturer had to modify the component to operate on the proprietary protocol, adding cost and complexity.

In 1987, a group of HVAC professionals initiated an effort to develop the BACnet protocol that became an ASHRAE standard in 1995. BACnet’s success in the HVAC arena has led to its extension to lighting controls, access control, and fire alarm systems by the development of object definitions that support the types of information and operational protocols, such as signal priorities and alarm states needed for the service. Today, BACnet is joined by other communication protocols such as ARCnet, LONWorks, and numerous proprietary protocols that are shared between equipment suppliers to facilitate interoperability.

Technology drivers

The rise of sustainability as a global objective is placing even more emphasis on building systems integration to achieve net-zero energy, or even net-positive energy, performance goals. Buildings are estimated to account for 40% of U.S. total energy consumption, so gains in building energy performance can have significant impacts on energy demand and associated environmental impacts.

The post-Sept. 11, 2001, era also has seen significant increases in the demand for security and the ability to respond to a range of hazards far beyond building fires. Emergency response plans must account for many types of incidents that may each require a different response by the building and its occupants, as well as the real-time information needed to manage these varying responses.

Many real-time information needs can be met with information already collected by certain building systems. For example, energy management systems do not need to maintain tight environmental controls on most unoccupied areas, so they will collect information on where people are absent, turning off lights and reducing ventilation. In an emergency response, knowing that certain areas of a building are unoccupied is valuable because it obviates the need to commit resources to search and rescue.

Data-rich environments

The availability of low-cost sensors has led to data-rich building environments that can respond automatically to changing conditions. Buildings in hot climates may include automated exterior shades that reduce solar gain, improving occupant comfort and reducing energy demand. Carbon dioxide (CO2) sensors are incorporated into building ventilation systems to detect the rise in CO2 associated with large groups of people in an assembly space and increase ventilation rates to avoid the “stuffy” feeling that derives from their respiration.

An example of how data from different building systems are being combined to respond to building occupants relates to access control, vertical transportation, and energy management. In some high-end office buildings, arriving workers scan their employee badges at the building entrance and they are guided to a specific elevator car operating under a destination dispatch system that knows their destination floor by their office locations. As they board the elevator, the building is turning on their office lights, adjusting the ventilation, and even powering up their computers. Systems that continuously track the location of individuals within the building have been developed but are not well accepted due to privacy concerns.

Fire alarm system interfaces

For many years, building fire alarm systems have been used to provide interfaces with building systems beyond the HVAC system interfaces. One example of such interfaces involves signals being sent from the fire alarm system to the building’s elevator control equipment to initiate Phase I emergency operations (or “elevator recall,” as it is commonly referred to within the United States) and return elevators to a designated level for occupant safety and to ensure elevator availability for emergency responders. Another example of fire alarm system integration is where the fire alarm system sends signals to a building’s security system to disable electronic locking devices in the means of egress pathway where such locks are permitted during nonemergency times to restrict the travel of occupants within a building.

Fire alarm systems have been successfully interfaced with other building systems to improve the overall level of safety in large assembly occupancy spaces, such as theaters and large entertainment facilities. In these buildings, it can be difficult for a fire alarm system to draw the attention of an otherwise-occupied person in the building. To address this, fire alarm systems are often interfaced to disable both the use of public address systems and the use of light-dimming equipment. Disabling these systems allows the fire alarm system to be heard and provides an adequate level of illumination for safe occupant egress when evacuation of a space becomes necessary.

Occupant self-evacuation elevators

In their 2009 editions, the International Building Code and NFPA 5000: Building Construction and Safety code both incorporated requirements for elevators to be used during fires for evacuations. Beyond the obvious advantages to people with mobility disabilities who cannot use stairs, evacuation elevators permit the timely evacuation of very tall buildings by all occupants. By using the elevators, it is possible to evacuate 100% of the occupants in any building of any height in less than 1 hour, without increasing the number, speed, or capacity of the elevators normally provided under typical elevator industry practice.

A key component of such systems is the coordination and data sharing between the elevators and the building fire alarm system, both to optimize the sequencing of the evacuation and to provide real-time monitoring for safe operation and active management.

One enabling technology was the development in 2007 of the Standard Fire Service Annunciator and Interface by a consortium of the fire alarm industry and the National Institute of Standards and Technology (NIST). This provides for a consistent user interface across the industry and permits information from many building systems already required to be displayed in the emergency command center of high-rise buildings to be collected in one location. This will both increase effectiveness and reduce resource demands on fire service operations.

In a culture that places an increasingly high value on the receipt of timely information across multiple media platforms, including smart phones, tablet PCs, text messages, etc., during emergencies, the development of mass notification systems (MNS) has accelerated rapidly in the recent past. These systems are typically designed to convey messages to a population that can be located within a single building, multiple buildings configured as a single campus, or multiple buildings in different locations during emergencies ranging from man-made events (accidental or intentional) and weather-related emergencies to business interruptions and the like. As MNS become more prevalent, they are frequently being introduced into facilities that contain a fire alarm system. This is especially common in college and university facilities installing MNS and an emergency communication system as part of a multifaceted means of complying with the Jeanne Clery Act requirement to provide timely warnings related to crimes that represent a threat to students or employees of a college or university. The Jeanne Clery Act requirements have gained nationwide attention in the response to the on-campus incident at Virginia Tech in 2007.

Recognizing this, the National Fire Protection Assn. (NFPA) has included in NFPA 72: National Fire Alarm and Signaling Code, 2010 edition, technical requirements for fire alarm systems that are integrated with MNS to reduce installation cost as well as the lifecycle cost associated with periodic maintenance of system components. One example of permitted integration of these two systems includes the use of voice communication speakers that broadcast messages from either system. As further indication of the recognized opportunity for these two systems to function in tandem, Chapter 24 of NFPA 72 requires that control units for MNS be tested for compliance with nationally recognized testing laboratory standards identical to those used for fire alarm control panels, such as ANSI/UL 864: Standard for Control Units and Accessories for Fire Alarm Systems.

Another technological development is the use of closed-circuit TV cameras that are capable of functioning as video image smoke detectors in addition to providing visual monitoring of spaces for potentially unauthorized access or other hazards. The technology functions by capturing images of a space in quick succession, scanning the captured images for obstructions or clusters of particles that may indicate the presence of smoke, and comparing the captured images using an algorithm for previously stored patterns that is indicative of a smoke condition. One advantage of using these systems where they are approved by the local authority having jurisdiction (AHJ) for smoke detection is that it eliminates the need for providing more traditional smoke detectors in addition to security cameras. Another advantage of using this technology is that the systems can be installed in spaces where more traditional spot-type smoke detectors are not always practical, such as high-ceiling spaces or vehicle tunnels where fire alarm systems are not typically provided, but where early detection of a fire can prove advantageous. Yet another advantage of video image smoke detectors is that they can be placed in spaces open to the elements where a traditional smoke detector installation would be infeasible.

Recently, the NFPA recognized that many of their technical standards for building systems include requirements for commissioning to ensure that these complex systems are working as designed. Further, the increasing application of integrated systems results in a growing need for coordinated testing to ensure the intended functionality. Thus the NFPA initiated a development project to produce a standard, NFPA 3: Recommended Practice on Commissioning and Integrated Testing of Fire Protection and Life Safety Systems, for systems commissioning that addresses commissioning of integrated systems.

The draft first edition of NFPA 3 covers both commissioning and periodic testing of building systems, and integrated testing with coordination among contractors. Coordinated testing has traditionally been problematic due to scheduling and other issues. In addition, increased integration raises concerns about shared liability where problems occur.

One of the most critical steps leading to a successful integration of fire alarm system, building automation system, HVAC system, elevator control, and so on, is the coordination during the early stages of a project between the design professionals responsible for the various trades, the owner/developer for the project, and especially the AHJ. As system integration is an evolving technology and not all AHJs are as quick to accept new technology as others, it is imperative to present planned system integrations during early stages such that the construction process is not delayed.

That being said, it must also be recognized that certain integrations require the use of a single manufacturer’s product line due to cross-listing requirements. Thus, it may be necessary for an owner/developer or general contractor to commit at an early stage to a single manufacturer. Where systems from different manufacturers are to be integrated, it is always useful to have a person familiar with the requirements for each system responsible for coordinating the integration and commissioning process.

Bukowski is a senior consultant with the Baltimore office of Rolf Jensen and Assocs. He joined RJA in 2009 after retiring from the federal government where he spent 35 years as a research fire protection engineer at the National Institute of Standards and Technology. Joyce is a consultant, and Venditti is an associate, both with the New York office of Rolf Jensen and Assocs.



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