Aspiration Smoke Detection Positioned to be More Flexible

By Andy Kuester

For environments where even trace amounts of smoke or water from sprinklers would be detrimental, engineers are incorporating highly sensitive aspiration detectors into facilities’ overall fire and life safety systems.

Fire and life safety systems have come a long way, consisting of an adept mix of detectors and detection mechanisms integrated to safeguard life and property. Because data, computers, inventory and telecommunications systems drive almost every aspect of our economy, sometimes even higher levels of protection are necessary. Aspiration smoke detectors protect the most critical assets and business operations where 24/7 continuity needs to be ensured.

Aspiration detection, which identifies a fire threat at the earliest possible stage, often prevents an actual fire and the associated damage for critical areas such as clean rooms, laboratories, telephone switching centers, computer rooms and museums or other facilities with irreplaceable assets. These very early warning fire detection systems can detect potential fires up to an hour before ignition.

Aspiration technology

The primary role of an aspiration system is to give adequate warning of smoldering fires, so that a fire can be extinguished before serious damage or lengthy interruption of service occurs. Because it provides very early detection, a potential fire emergency can become a simple maintenance task, thus helping to avoid asset loss and business disruption, as well as water damage from activated sprinklers.
Aspirating smoke detectors are highly sensitive and can detect smoke before it is even visible to the human eye. Consider the semiconductor industry, where clean rooms and photo bays have no tolerance for particle generation. “Because a fire generates large quantities of particles, such an incident would be significant to the operation and would potentially damage sensitive equipment and product,” says Beth Tshudy, EHS manager, Analog Devices Inc., Wilmington, Mass. “The key is that you want to find it in its early stages. An aspirating system has been known to detect a fried circuit board before anyone could even smell it.”

Aspiration detection systems have traditionally been intended for critical applications that count on catching potential fires as early as possible. Environments such as telecommunications and financial centers remain the mainstream markets for aspiration, where highly sensitive fire detection is necessary to ensure continuity. However, aspiration has proven beneficial for reasons other than just business continuity or asset protection.

Aspiration’s flexibility

Difficult-to-reach areas and hazardous conditions present challenges for fire protection engineers and installers. Aspiration detection systems can be designed into the fire protection mix to help solve these design challenges. Options for designing aspiration detection systems, along with, or in place of, other fire systems and detectors, can eliminate hazardous situations for maintenance personnel. Aspiration systems can provide a safer working environment, eliminating the need to enter high-voltage or high-ceiling environments to test and maintain detectors.

Dan Ubelhor, corporate engineering manager for Koorsen Fire & Security in Indianapolis, designs aspiration detection into fire safety systems and appreciates the flexibility of aspiration, especially for testing. “Codes require testing of the detectors, but it is difficult, if not impossible, to test them if they are located in high-area environments,” he says. “Sampling pipes can be installed in any area and extended out to reachable levels where the piping can easily be tested.” Tests can include blowing sample smoke into the piping system.

Ubelhor has designed aspiration systems into air handler units and claims the systems work well in high air flow environments. “A lot of times, normal smoke detectors are not listed for high air flow and may not be able to catch the smoke in high air flow areas. Aspiration detection systems actually draw the air in and are well designed to situate in high air flow movement areas,” he says.

Typically, high air exchange areas have some form of mechanical ventilation to maintain constant or cyclical air flow for heating, cooling or other special environments. Smoke tends to travel with the air flow, hence, positioning sampling pipes near the return of an air handling unit or heating/air conditioning unit ensures early detection of particulate in the area.

Ubelhor also uses aspiration systems when designing fire systems for high-ceiling environments, such as atria or warehouses. “Many times we’ll run air sampling systems across the air intakes in high atrium areas in order to increase the sampling volume. This would be done instead of sampling at the ceiling level where the air flow would present a minimum amount of air particles,” he says.

Large volume areas and areas with high ceilings, where a condition called stratification can occur, require special design considerations for the pipe network design. Smoke rises until there is no difference in temperature between the smoke and the surrounding air. Stratification may occur in areas where the air temperature may be elevated at the ceiling level, especially where this is a lack of ventilation.

In applications where stratification is likely, conventional pipe network sampling may not be effective. One way to overcome this problem is to create a vertical sampling pipe, in addition to the horizontal pipe network on the ceiling. The vertical sampling pipe has sampling holes at various heights to sample within any stratification layers in the area. Warehouses with high ceilings are a good example of this type of environment, where having multiple pipe configurations at different sampling levels could work well.

Difficult or dangerous installations

Scott Golly, senior engineer at Hughes Associates Inc., in Baltimore, has also designed aspiration detection into fire systems to overcome positioning difficulties. “A good application for aspiration is when it is difficult to get to the smoke detectors for maintenance,” he says.

UPS battery rooms, for example, do not require the very early detection afforded by aspiration technology. Installing and maintaining smoke or heat detectors above high-amperage UPS batteries, however, can be dangerous. “It’s just an unsafe work environment,” states Golly. “Instead, an aspirating smoke detector can be placed on the wall with an array of sample holes and piping installed above the batteries. A remote sample point for each pipe run can then be extended down the wall, positioned to allow testing and maintenance of the system without putting employees at risk.”

Golly says that aspirating detection is also being used more frequently for positioning in ambient environments, where the environment needing detection is not within the UL listing of a normal smoke or heat detector. Aspiration systems can withstand hostile environments, including places that are very hot, very cold, wet or dusty, making them good candidates for engineers who need to install reliable, trouble-free detection.

Sampling pipe network stays out of sight

When it’s more beneficial for the system to be hidden, such as for safety or aesthetic reasons, sampling pipes can be installed in the ceiling or the lighting, typically within capillary tubes. This approach works in correctional facilities; aspiration offers a vandal-proof way to detect smoking or other conditions without sounding a false alarm.

Aspiration technology with hidden piping is also useful for protecting historical buildings, as well as for the irreplaceable assets inside museums and art galleries. Concealing the sampling pipes retains the authentic look of preservation projects, while offering the highest level of protection.

The main pipe network is installed in a ceiling void, and capillary tubes are branched off at regular intervals. These capillary tubes are used to monitor the protected area by projecting through the ceiling covering, while the main pipe network remains hidden.

In industrial environments, such as a spray booth or a wastewater treatment facility, some aspiration systems can be programmed at the highest level of sensitivity to tell the difference between a dirt particle and smoke particulate. Aspiration systems do require more frequent maintenance in dirty environments, however.

Local codes and regulations can determine the size and spacing between the sample holes in a network, making them a critical part of any pipe design. These requirements change, depending on the type of environment monitored. Local codes and standards take precedence over any parameters suggested for aspiration systems.

Aspiration detection systems provide a vast span of detection. Not only is there the flexibility to move the piping for different applications but these systems also have unique capabilities for issuing multiple warning levels. The system can be programmed to send a signal to the building alarm system and to limit automatic initiation of a sprinkler or other type of suppression system if certain extreme, pre-set conditions are met.

More than ever, companies want the security of knowing that their assets and personnel are safe from fire. Integrating an aspiration detection system into the overall fire and life safety system can provide quick detection and solve challenges, such as positioning, aesthetics, security and life safety, in both traditional and unique applications.

Andy Kuester is product marketing manager for Aspiration Detection, System Sensor.