Fire, Life Safety

Three technologies to watch in fire, life safety

While some of these systems have been available for some time, they are not yet readily accepted by fire and life safety experts

By Joshua D. Greene, PE, Simpson Gumpertz & Heger, Waltham, Massachusetts July 12, 2019
Figure 3: An oxygen reduction system provides fire protection by removing one of the primary elements of the fire triangle: oxygen. In this case, oxygen isn’t completely removed, but rather the oxygen content in a room or space is reduced below the level required to sustain combustion. Courtesy: Simpson Gumpertz & Heger

Learning objectives

  • Gain a better understanding of the status of three newer technologies in the fire protection industry. 
  • Understand the limitations and difficulties in gaining acceptance of such technologies. 
  • Recognize the importance of continued advancement and innovation in fire protection on society. 

Many new fire and life safety technologies and innovations remain notable, and they may yet achieve greater use and application in the future. It is possible that some or all of them have achieved greater use in a specific market. There are several current products and systems available today.  

Video image smoke detection: VISD technology and devices have been available for more than a decade. The concept of VISD is relatively simple: a camera is used to “see” a fire event, which is recognized through the use of video analytic algorithms that analyzes the camera images. Once the algorithm analysis identifies a pattern that is indicative of smoke, an alarm signal is initiated.  

Video image smoke detection can be accomplished using a stand-alone camera designed specifically for that use, with the ability to perform the analytic algorithms within the camera. The stand-alone cameras can be used for security purposes as well as fire/smoke detectors. These cameras generally can be compared to optical flame detectors, where the processing occurs at the unit and it serves as an advanced spot type detector within a fire alarm system framework 

The other VISD option houses the video analytics within a central processing unit, to which internet protocol security cameras can be connected. Because the image evaluation occurs at the central processing unit or server instead of at the camera, these types of systems can utilize existing security cameras, provided they are capable of providing an image that can be processed. Cameras can be either analog or digital devices, providing flexibility for applications where an existing closed-circuit TV security system is installed already. 

Figure 1: A video image smoke detection camera has analytic algorithms processed within the camera. Courtesy: Simpson Gumpertz & Heger

VISD systems have been recognized as fire protection devices for years, with requirements first added to NFPA 72: National Fire Alarm and Signaling Code in the 2007 edition. Given their proprietary algorithms and image-based method of detection, NFPA 72 does not have prescriptive spacing or similar requirements for VISD, but rather requires that these systems be designed using performance-based design. Both stand-alone camera and the CPU-based systems have been listed by agencies such as UL and approved by FM Global. 

VISD typically is marketed by manufacturers for use in largevolume spaces such as warehouses, large industrial facilities and power generation plants. They were originally marketed for maritime uses such as engine rooms because of the importance of detecting a fire quickly on ships in areas where equipment can shield fires from early detection by other means. VISD also was developed for detection at exterior facilities such as oil rigs and mines. 

Given society’s trend toward increased security through the use of cameras, it is somewhat surprising that it isn’t seeing more widespread use as part of an integrated security and fire alarm solution. Part of the problem may very well be that fire protection and security integration itself is still not prevalent, as these systems are treated separately by designers despite their commonalities and often complementary individual technologies.  

Another deterrence may be the fact that designs must be prepared using performance-based initiatives and manufacturer specific requirements instead of simple application through prescriptive requirements. Owners and end users may be reluctant to use VISD because of perceived difficulties in getting such systems competitively bid and accepted by authorities having jurisdiction. 

Dynamic wayfinding devices/systems: Another technological advancement that has been percolating in the design and construction space for years, but that hasn’t seen widespread implementation, is dynamic wayfinding devices or systems. This is a fairly general term and can be applied to devices or systems that offer dynamic audible and/or visual signals to enhance occupant awareness of exits during an emergency event.  

Recent articles (Consulting-Specifying EngineerMarch 2019 and July 2018) discussed dynamic signage technology and its potential improvement to occupant awareness and movement, especially for transient occupants who have little knowledge of a building or space. Dynamic signage is intended to provide building occupants with visible instructions or cues based on realtime information of an emergency event instead of a static exit sign.  

Among the benefits is the ability to overcome human behaviors such as cognitive disregard for indicators that may help them recognize an exit such as typical illuminated exit signs, a concept the author of the July 2018 article terms learned irrelevance. For fire events, a conceivable downside to dynamic signage is that the reduction in visibility caused by smoke migration along the paths of egress could render the signs unreadable. 

On the flipside of the sensory coin for dynamic wayfinding technology is audible wayfinding, often referred to as directional sound devices. Instead of providing visual cues to occupants, directional sound devices offer audible signals that inhabitants are expected to follow to reach an exit. The audible signals can be in the form of a unique sound or pulse pattern or a prerecorded or live voice message.  

One benefit to this technology over visual wayfinding is that sound does not require line of sight, so a directional device can effectively cover a large volume with fewer devices than a visual device. It also has the ability to alert occupants in smoke-filled environs that impede visual signage. However, because sound passes through multiple mediums, including solid objects and air, it can be more difficult for occupants to determine the source of the sound as the distance from it increases. 

A prime motivator for implementation of a new technology is its recognition in codes and standards. Building design and construction is reliant on prescriptive codes such as the International Building Code and NFPA 101: Life Safety Code to set minimum requirements for buildings and structures. Dynamic wayfinding can be considered an egress enhancement over minimum exit signage requirements, so it wouldn’t be expected to find its way to the code without an outside catalyst such as an event or use.  

In addition, because dynamic wayfinding devices represent a new concept for building occupants, they may need to be trained on how the devices work and how they should respond to the devices. This is especially true of audible wayfinding devices that emit a distinctive sound instead of a voice instruction, as occupants would not be expected to automatically recognize that they should move toward the sound to find an exit. 

Figure 2: A video image smoke detection system can use a security camera and central processing unit with analytic algorithms. Courtesy: Simpson Gumpertz & Heger

Oxygen reduction systems: ORS, also sometimes referred to as a hypoxic air system, provides fire protection by removing one of the primary elements of the fire triangle (or fire tetrahedron, if you prefer): oxygen. In this case, oxygen isn’t completely removed, but rather the oxygen content in a room or space is reduced below the level required to sustain combustion. 

Oxygen reduction systems accomplish this through the use of one or more hypoxic generators that exchange ambient air with lowoxygen air, typically at an oxygen concentration between 14.5% and 15.5%. The lowoxygen air fills the room or space being protected and limits the ability for a fire to ignite or spread. The oxygen concentration does not completely inhibit fire, as fires can exist within these concentration levels. The system actively monitors the environment of the room through the use of oxygen sensors and turns generators on and off as needed to maintain the desired concentration.  

From a regulation and standard standpoint, ORS is an outlier, not fitting into the typical fire protection categories of detectionnotification or suppression. It is certainly not a fire detection system, as there are no active components to detect a fire event or activate alarm notification. Efforts were reportedly made to categorize these systems as a fire suppression system comparable to clean agents, but they don’t really fit that area either because they don’t have an active suppression mode. Several manufacturers use the term fire prevention for their systems. 

Hypoxic air systems offer some clear advantages for specific situations. Because the systems manipulate the balance of oxygen in air, there are no active agents or materials involved with the systems. Therefore, they could fit into portions of the clean agent market, where application of water or byproducts of suppression agent decomposition may harm high value assets. Unoccupied spaces with specific hazards where total flooding carbon dioxide systems are currently employed also offer a good fit. Finally, specific facilities without available water supplies or where the ability to provide, service and/or replenish other agents in a timely manner is difficult may benefit from these systems. 

ORS also pose some complications for widespread use and acceptance. In the United States, the reduced oxygen environment is below the Occupational Safety and Health Administration oxygen concentration threshold for occupancy without personal protective equipment. This alone reduces the utility of such systems to rooms or spaces that are unoccupied.  

Because the systems have no active fire detection devices or fire suppression agents, ORS rely completely on their ability to maintain a reduced oxygen environment to provide protection to a room. As a result, prudent system designers will need to include a method for sustaining the operation of the generators upon loss of power as well as potential equipment redundancies to account for a generator failing or being taken out of service for maintenance or repair. 

In the U.S., hypoxic air systems would appear to have greater issues to overcome to gain widespread use than either video image smoke detectors or dynamic wayfinding devices/systems. The first hurdle to overcome is the lack of a standard or regulation for their design, installation and inspection, and testing and maintenance. The next issue is the limitations on application, as using these systems in areas with occupants does not meet OSHA requirements. There are certain applications where hypoxic air systems may be superior to more traditional fire suppression systems and this discussion is not intended to discount the plausibility of the technology or overall concept. However, practical difficulties may limit its use until successful case studies with proven applications are developed. 

Figure 3: An oxygen reduction system provides fire protection by removing one of the primary elements of the fire triangle: oxygen. In this case, oxygen isn’t completely removed, but rather the oxygen content in a room or space is reduced below the level required to sustain combustion. Courtesy: Simpson Gumpertz & Heger

Future changes  

Over the past few years, the growth of the smart home and smart device technology market has been rapid. Many homes and some businesses employ some form of smart technology as part of the daily routine. The internet of things has become an industry term across various workflows and applications, from engineering to education to finance. It stands to reason that smart technology will cascade to fire protection systems as well. If nothing else, data collection and analysis inherent to internet of things should assist the fire protection community in identifying trends in fire events, device or material reliability, and opportunities to enhance or update existing technology to provide greater fire and life safety. 

If history has shown us anything, its that fire protection is not and cannot be a stagnant industry. Historic fire events have identified weaknesses and forced important changes to address those weaknesses. Hazards continue to evolve, which requires constant attention and innovation to mitigate their impact on the public.  

As the three technologies discussed here attest, technological advancements in fire protection often occur over an extended time frame instead of having an immediate impact. This may be due to society’s reliance on these advancements to provide an acceptable level of safety. There is little room for error in the industry, so new devices, systems and concepts must be rigorously evaluated and tested before being applied. 

Joshua D. Greene, PE, Simpson Gumpertz & Heger, Waltham, Massachusetts
Author Bio: Joshua D. Greene is an associate principal at Simpson Gumpertz & Heger. Greene specializes in the practical application of fire protection principles in support of unique designs. He is a member of the Consulting-Specifying Engineer editorial advisory board.