For applications that require supply and return detection, InnovairFlex has a 2-to-1 sensor to power board capability using the D4120 and the D4S (see image at left). This capability eliminates the need to run power to a second power board for these applications, significantly reducing installation time and costs. It also reduces maintenance and testing costs by enabling the testing of two sensors from a single location. For more information, visit www.systemsensor.com/flex.

This guide provides an overview of System Sensor fire and smoke detection technologies. It is not a comprehensive overview of all System Sensor products; rather, the objective is to show how System Sensor has detection technologies that are suitable for different fire and environmental scenarios.

Please consult with System Sensor for specific product information, and for notification products and other systems not covered in this guide. Also, consult with your Authority Having Jurisdiction for code applicability before selecting a system.

Conventional Smoke Detectors

System Sensor conventional smoke detectors include the 100 Series detectors and the i³ Series, amongst others. These photoelectric 2- and 4-wire spot-type detectors can include a built-in sounder, thermal sensor, and Form C relay to meet a range of requirements. Conventional detectors specialize in the detection of slow, smoldering fires with particulates in the 0.4 to 10.0 micron range. These detectors have an approximate maximum coverage area of 900 sq. ft. (30 ft. x 30 ft.).

Conventional smoke detectors are a practical choice for typical applications when they don’t require an intelligent device and the primary objective is to protect lives from fire and smoke. For example, they are often ideally suited to general commercial and multi-family residential applications.

Intelligent Smoke Detectors

Many of today’s fire systems are “smart” or “intelligent.” The components of these systems are able to engage in two-way dialogue, analyze complex environments, adjust their own sensitivity levels and make “educated” decisions based on stored data.

One important benefit of intelligent (addressable) smoke detectors is the ability for the panel to pinpoint detector locations for quick identification of detectors that are in alarm, have been tampered with or require maintenance.

System Sensor produces a full line of intelligent smoke detectors, from standard photoelectric smoke detectors (2251B) used in many commercial applications, to a host of specialty detectors, some of which are detailed in this guide.

Aspiration Smoke Detectors

Aspiration smoke detectors draw air into a high-sensitivity sensor through a pipe network to provide Very Early Warning Fire Detection. This approach enables these detectors to protect mission-critical facilities and high-value assets from the faintest traces of smoke – even in highly challenging environments.

The System Sensor FAAST® Fire Alarm Aspiration Sensing Technology (8100) includes unique dual vision sensing technology. This sensor uses an extremely sensitive blue LED to provide Very Early Warning Fire Detection, and an infrared laser to identify nuisances like dust that can cause false alarms and downtime. The detector interprets signals from both sources to provide the earliest and most accurate warning of the widest range of fires available. FAAST includes five programmable alarm levels and ten pre-alert particulate levels, so thresholds can be set to specific site requirements. System conditions are displayed at the user interface and at a fire alarm control panel via relays. With integral TCP/IP Ethernet connectivity, FAAST provides e-mail notification of device status updates and can be monitored remotely via its PipeIQ™ software or a smart phone through any Web browser. FAAST’s remote monitoring capabilities enable facility managers to mount an appropriate response to any situation.

A single FAAST unit can protect up to 8,000 sq. ft. with a wide sensitivity range of 0.00046 to 6.25 %/ft. obscuration. Because FAAST can be installed remotely while sampling points can be run into the protected area through the pipe network, it can be an ideal choice for challenging environments, such as cold storage facilities or medical testing rooms. The pipe network can also be hidden above a ceiling or in a floor cavity to eliminate tampering in public areas or to maintain a facility’s aesthetics while protecting important assets, such as in a museum. And with its ability to provide the earliest, most accurate detection available, FAAST can also be ideal to protect mission-critical environments, such as telecom/data centers and hi-tech fabrication facilities.

BEAM Smoke Detectors

System Sensor single-ended BEAM smoke detectors (BEAM1224 conventional, BEAM200 intelligent) are designed to save time and money and provide better detection capabilities for many open-area and high-ceiling applications. BEAM detectors provide a very wide coverage area – up to 19,800 sq. ft. (330 ft. x 60 ft.) and are well suited for applications where it is difficult to install or maintain traditional spot detectors or where smoke might not reach the ceiling due to stratification.

These detectors include an 8-inch reflector that is mounted opposite the transmitter/sensor, so only one device needs to be wired. They have a wider operating temperature range than typical spot detectors and work well in colder environments, such as cold storage warehouses and sports arenas, as well as other high-ceilinged areas like atria, lobbies, gymnasiums, and factories. BEAM detectors also include a full line of accessories, such as heavy-duty mounting kits, heater kits, long range kits, etc., to help installers meet a variety of application requirements.

Duct Smoke Detectors

A duct smoke detector is a device or group of devices used to detect the presence of smoke in the airstream of ductwork sections of the HVAC air-handling systems used in industrial/commercial facilities. Duct smoke detection not only serves to assist in preventing the spread of toxic smoke and combustion gases, it can also be used to assist in equipment protection applications.

Made to operate in air velocities from 100 to 4,000 feet per minute, System Sensor InnovairFlex™ photoelectric duct smoke detectors (D4120 conventional, DNR intelligent) utilize a pivoting housing that fits both square and rectangular footprints on round or rectangular ductwork. These detectors provide the superior false alarm immunity necessary to reduce callbacks in duct applications that are prone to have nuisance conditions. InnovairFlex detectors also use patented sampling tubes that plug into these often difficult-to-access detectors from the front or back of the device without the need for tools.

The InnovairFlex line includes specialty detectors that are designed specifically for challenging or unique duct smoke applications. The DNRHS high-sensitivity duct smoke detector uses a highly sensitive laser sensor to provide very early warning of fires to protect high-value assets and mission-critical operations from fire and the spread of damaging smoke through air management systems.

NEMA 4-rated InnovairFlex watertight duct smoke detectors (D4120W conventional, DNRW intelligent) are built to operate on rooftops or other challenging applications without the need for bulky or costly enclosures. These detectors can operate in airflow speeds from 100 to 4,000 feet per minute, temperatures from –4°F to 158°F and humidity ranges from 0 to 95 percent (non-condensing). In addition, the watertight, UV-resistant housing provides protection against rain, windblown dust and dirt, splashing, and hose-directed water.

Multi-Criteria Fire Detectors

Intelligent multi-criteria detectors monitor more than one product of a fire in order to achieve higher levels of sensitivity, detect a wider range of fires, or improve accuracy. The Advanced Multi-Criteria Fire Detector (2251-COPTIR) combines four sensing technologies – smoke, carbon monoxide, heat, and infrared – with intelligent detection algorithms that enable the detector to respond very quickly to an actual fire while maintaining the highest levels of nuisance immunity available.

This detector is ideal for challenging applications where ambient conditions have the potential to cause nuisance alarms in typical spot detection technologies or where nuisance alarms can be especially costly or dangerous, such as in theaters, medical facilities, dormitories, senior living centers, financial trading centers, telecom networks and manufacturing facilities.

Another intelligent multi-criteria detector, Acclimate™ (2251TMB), combines photoelectric and 135°F thermal sensor signals to provide early and accurate fire detection. To further enhance its speed and accuracy, Acclimate can automatically adjust its sensitivity within specified parameters. For example, if usage for a protected area varies, the detector will adjust itself to provide the appropriate sensitivity to suit current environmental conditions. Other System Sensor detectors, such as the Advanced Multi-Criteria Fire Detector and FAAST, also utilize Acclimate’s self-adjusting technology.

Heat Detectors

System Sensor 400 Series and 5600 Series heat detectors include combination fixed and rate-of-rise plug-in heat detectors and mechanical heat detectors. These detectors offer a low-cost means for property protection against fire and for non-life-safety installations where smoke detectors are inappropriate.

Heat detectors are appropriate for areas with unsuitable conditions for smoke detectors, including areas that experience rapid changes in temperature or where high ambient temperatures exist, such as storage facilities, garages, mechanical rooms, kitchens and other service areas.

To learn more about how System Sensor fire detectors can be used in a variety of projects and applications, visit systemsensor.com/appguides.

These relays also act as accessories that interface with other System Sensor protection systems, such as duct and conventional smoke detectors, and bring an additional level of security and safety to these systems. Relays can be configured on either a fixed basis or can be programmed to activate under specific input conditions.

Examples of relay functions include:

• Relays can hook to HVAC system detection to prevent dissemination of smoke through fans, dampers and air-handling systems.

• For doors, the relays can be programmed to close doors to certain building zones to keep smoke from spreading or to unlock doors to improve egress.

• Elevators can be controlled by relays to ensure appropriate elevator recall operation.

Relays can also interface with voice evacuation, security and mass notification systems to ensure, for instance, that building management and occupants have accurate, up-to-the-minute information regarding emergency situations that impact other components connected to the fire system. Monitoring of kitchen systems and suppression systems may also be enhanced with relays.

System Sensor offers three types of relays, each of which feature activation LEDs and is available in multiple voltages to accommodate different applications. The three available series of relays are: the epoxy-encapsulated potted with pigtail series relays; steel enclosure series relays, which are mounted into a steel enclosure with a removable front cover for easy access; and track-mount series relays, which have terminal strip field wiring connections.

System Sensor technical support can advise which relay series is best suited for any particular facility or application.

Q. How much responsibility does the architect assume for life-safety matters?

King: The architect leads the design, and the engineer follows up with the details. The engineer is responsible for the technical aspects of making sure there is adequate egress lighting and signage and that they are powered correctly. The location of these elements is up to the architect.

Q. Who is responsible for code compliance?

King: It depends on the components. For example, lighting has to be compliant with the National Electrical Code®. Therefore, the engineer would be in charge. In terms of suppression, you would have a licensed professional designing the sprinkler system. Both of these items are outside the scope of the architect’s work, but overall compliance with the building code is the architect’s job.

Q. Are clients more concerned with initial cost or operation/maintenance cost?

Wells: That varies. Clients with low operating budgets are typically willing to pay more upfront for lower operational costs, whereas others are less concerned with the long-term operating costs and are more concerned with the initial cost. We try to determine which approach is most desirable for the individual client. The duration of the lease, the life cycle of the equipment specified for the space, and the initial capital spending available are a few factors that need to be analyzed to determine the appropriate specifics for the design.

Q. Will owners who plan to keep the building spend more money initially for greater savings in operation and maintenance?

King: That’s true. And then there are some who plan some obsolescence into their development and they add more time for that cost over the life of the space. It really is not that significant to them.

Q. What if you could cut 40 percent current draw from the fire notification device circuit?

King: In terms of the overall building, it really is not a significant amount. But at the end of the day, savings add up. You need to take a holistic approach. Even if it is more expensive, sometimes the expense is minimal in terms of what the building could achieve in the long run with energy savings.

Q. Do larger retailers tend to build their own facilities or take over space?

King: It’s a mix. It can vary from location. You might have the same retailer in different locations go into a strip mall or stay in their own box. It’s really location, location, location.

Q. Do the larger retailers usually rent or own their facilities?

King: Both. It just depends on the location and the availability of property. If there is not much land available, they’ll go into an existing facility or have it built to suit their needs.

Q. What do you recommend when a client is looking to take over existing space?

Wells: The space should be appropriate for the proposed use in terms of construction classification and square footage. The function and proposed floor plan should be reviewed to ensure that the suppression system and fire alarm system are adequate and to determine whether redesign of the items will be necessary. The building codes have several requirements: providing lit exits, lights on battery packs that provide a path to the nearest exit and minimum travel distance to the nearest exit. The design should provide a clearly evident means of egress. Clear identification of egress paths is vital because patrons may be unfamiliar with the space. Some factors for egress design consideration include size, clarity, lighting and signage.

King: There are a lot of factors that could be involved based on the differing uses. Think of an Internet café, which would have a wide, open space, versus a craft store that could have a lot more shelves, material and flammable elements. You may need to have a suppression system engineered, depending on how the store is laid out. Or, you may need additional smoke detectors to trigger the alarms. You definitely need a design professional to evaluate the space.

Q. At what point should building space be evaluated? What are the code implications?

King: The time to review and evaluate a facility is when you are doing alterations to an existing facility. In Ohio, you do not have to bring the whole building up to current standards, depending on the scope of the work you’re doing. It really is an interpretation by the building official. Design professionals with experience have a feel for what will be permissible and what will not be.

Q. What do you do to prevent false alarms? How do false alarms affect your clients and your business?

Wells: The detection and notification systems should be maintained. Facility operations should budget funds for adequate testing and maintenance of these systems. Designers should locate these items appropriately and ensure installation is tamper proof. It is important that the designers provide systems that operations can maintain. Businesses are exposed to shrinkage due to false alarms.

Intelligent air duct smoke detectors mounted on the computer room air-conditioning unit reduces aisle widths from 30” to less than 24”.

Bell Canada turned to System Sensor, which had the product to do the job: its new laser-based model 7251 DH intelligent air duct smoke detector, the company’s latest addition to its high-sensitivity detection line-up. The product combines System Sensor’s high-sensitivity laser sensor with its industry-leading duct smoke detection capability.

The detector not only provides very early warning, it screens out false alarms with a set of sophisticated logic algorithms. It was created to work in such areas as telecommunications rooms and computer server rooms, which have high air flow and several air changes per hour.

These types of environments are different than a static air environment where fire generates smoke that rises to the ceiling in a concentrated form. In a telecommunication center, the high air flow causes air mixing and smoke dilution. That makes detection by any means other than high-sensitivity detection slow and less responsive. NFPA 76, Standard for the Fire Protection of Telecommunication Facilities, requires very early warning fire detection in order to detect small incipient stage malfunctions that could lead to fire conditions. A manual response in this early stage normally terminates the malfunction.

At elevated air flows and in some other locations the smoke does not have an opportunity to rise to ceiling-based detection, making the detection of the air flow at return grilles a very important part of the smoke detection system. Very early warning detection requirements for return air require an air aspiration port or spot detector for every four square feet of return grille area. This often results in an overabundance of detection technology in vulnerable placement areas.

Telecommunication equipment spaces are frequently tight. Placing spot detection or air-aspiration tubing in front of air-handling equipment to monitor the air flow often creates issues with potential injury and/or equipment damage. It can also create interference with HVAC equipment maintenance if the narrow aisles become partially obstructed.

System Sensor responded to Bell Canada’s request for very early warning fire detection performance with the conventional duct detection configuration. Once the new duct detection technology was listed by Underwriters’ Laboratories of Canada, Bell Canada installed the duct-detection system in one of the facilities that had recently been upgraded to laser spot detection. The ceiling-mounted detectors were installed to comply with NFPA 76 prescriptive requirements. The return air early detection system design was based on NFPA 76 performance-based requirements. In order to determine how well the new system worked, Bell Canada conducted the performance-based testing requirements outlined in NFPA 76 Annex B.

Then there are times when there’s nothing wrong with the available technology. It’s just that inventive minds think of ways that the technology can be better utilized to serve our customers’ needs. That’s what happened in the case of several of the new products that System Sensor is announcing in this issue of LifeSafety.

The first is our new Advanced Multi-Criteria Fire Detector, which acts as four sensors in one. System Sensor has manufactured products that provide smoke, heat, carbon monoxide and flame detection, predominantly utilizing singular sensors. In the interest of offering the ultimate in fire detection while addressing the longstanding problem of nuisance alarms, we have brought these four detection elements together with advanced, logical algorithms that work collectively to analyze and determine whether there truly is a fire.

The second innovation is the new CO1224T carbon monoxide detector, which provides a simple, inexpensive test to confirm the CO cell’s functionality using canned CO. A one-second test spray lets you rest assured that the CO sensor is functioning properly — a feature that puts System Sensor well ahead of the upcoming NFPA 720-2009 standard for CO devices.

Our third solution, which reflects your feedback on our Innovair™ line of duct smoke detectors, is the new InnovairFlex™ series duct detectors. InnovairFlex detectors offer the ultimate in flexibility and functionality, whether it’s broader environmental specifications, greater wiring capabilities, enhanced sensor status indication or even the detector’s physical footprint.

System Sensor engineering and product development teams continuously strive to not only improve existing detection and notification products, but to define the future standard for the industry. Interestingly enough, our methodology is fairly commonsensical — seek to identify and understand customers’ unmet needs. However, it’s the combination of our customer focus and the application of our leading technology that allows us to continually deliver innovative solutions such as these.

Thank you for the continued opportunity to serve your fire and life safety needs.

Tom Potosnak

General Manager
System Sensor U.S.

Tenants come and go. One month, an area might be filled with a maze of cubicles, the next, it may be a suite of private offices. As each new company takes over space in a building and adapts it to their needs, there’s a completely different set of fire-protection guidelines. However, the same versatility of space that makes a building desirable for renters can also present challenges when it comes to fire protection.

To guard against hazards associated with changing uses for building space, it is important for a fire-protection system to provide “total coverage.” Defined by the National Fire Protection Association in NFPA 72 guidelines, total coverage is achieved with the proper type of detectors installed in appropriate locations.

Where to Install Detectors?

The goal of a fire-detection system is to provide an accurate, early warning of a developing fire in all areas of a building. Even pockets of unoccupied space require protection because detectors may not quickly sense a developing fire on the far side of a wall or behind a closed door, allowing damage to multiply needlessly.

The correct placement of detectors is also important for reliable operation. In general, when only one detector is required in a room or space, it is best to install a ceiling-mounted detector as close to the center of the room as possible. If a central ceiling location is not viable, for example, due to wiring constraints, the detector must have sufficient “open space,” with its edge no closer than 4 inches to a wall. Likewise, a wall-mounted detector must clear between 4 and 12 inches from the top of the detector to the ceiling.

Another consideration for a total coverage plan is the proximity of detectors to the air-handling system. NFPA 72 discusses the potential for detector malfunction if installation is in the path of an airflow supply or return duct. A smoke test to monitor particulate travel-direction and velocity is helpful in determining detector placement. Smoke tests reveal potential causes of unwanted alarms, such as an air stream directed at the detector, which could result in dust accumulation that alters sensitivity levels.

How to Space Detectors?

Spacing detectors 30 feet apart to protect 900 square feet is the NFPA 72 standard for areas with smooth ceilings and no physical obstructions between ceiling and room contents. An example of an obstruction is floor-to-ceiling shelving stacked with materials. Variables for ceiling height may also be calculated into spacing requirements based on the amount and nature of combustibles present.

To determine appropriate detector coverage for the standard 30-foot spacing, a simple technique is to map the shape and dimensions of an area. Then, draw a circle with a radius of 21 feet. A single detector may protect any square or rectangle that fits within the circumference of that circle. The same technique shows that in a hallway measuring 10 feet wide, two detectors can protect up to 82 feet of the length.

What Type of Detectors?

To answer that question is to understand the use and contents of a particular area. For example, ionization smoke detectors are quicker to detect flaming fires, such as those commonly found in chemical-storage areas, rather than slow, smoldering fires that most typically occur in offices. Ionization sensors almost immediately recognize fires characterized by combustion particles from 0.01 to 0.3 microns. However, ionization sensors offer limited or slower capabilities when installed in high-altitude locations or near high-humidity sources, such as kitchens or shower rooms.

Photoelectric smoke detectors, on the other hand, quickly respond to smoldering fires characterized by combustion particles from 0.3 to 10.0 microns. This type of detector will instantly identify visible white smoke, but will be slower to respond to black smoke produced by plastics or rubber.

A common solution to detect both types of stimuli quickly is to install a multi-criteria detector that monitors particulate detection in tandem with a thermal-sensor input. Together, the two signals are cross-referenced by an on-board microprocessor that uses algorithms to “process out” false alarms while enhancing the response time to real fires (see “NASA Researches Multi-Criteria Detectors”). By monitoring the current signal values of each sensor as well as their trends, such as increasing heat or a decreasing photoelectric signal, multi-criteria detectors actually “learn” the environment, which helps to better reject nuisance alarms and maintain heightened sensitivities.

Which Code to Follow?

The location, quantity and type of detector should be determined by the use, size and contents of the space. However, total coverage must ultimately coincide with the guidelines set by the Authority Having Jurisdiction.

Several independent organizations write model building and fire codes that are commonly adopted by local and state governments throughout the United States. While variances should be expected in individual municipalities, most regulations are based on three organizations’ codes:

• Building Officials and Code Administrators’ National Building Code (BOCA): Northeast and Midwest

• International Conference of Building Officials’ Uniform Building Code: West and Southwest

• Southern Building Code Congress International’s Standard Building Code: South and Southeast

The International Code Council Inc.’s International Building Code/International Fire Code combines the above codes into a single set of model building and fire codes. Some states have adopted the International Building Code and International Fire Code.

Q. How do you manage fire safety in more than 270 facilities?

A. The size of the district does create challenges. South Florida is continually growing. We’ve added 20 new schools in the past eight years and expanded another 40.We also use more than 2,000 modular buildings for classrooms. Our facilities department oversees the majority of this new and renovated construction, and all aspects of life safety are managed through a coordinated effort among the physical plant operations, facilities, and internal building and safety departments.

Needless to say, it’s a large task and communication is the key. Maintaining multiple technologies is another constant challenge due to the diversity and age of the fire-alarm systems in our facilities. Fortunately, several of our department technicians are NICET certified, and all are factory trained on a variety of manufacturers’ technologies: Simplex, NOTIFIER, FCI and Fire-Lite. We have, therefore, become an all-inclusive service organization and can address the majority of service issues internally. Coordinating with all these departments, we formulate strategies that allow us not only to address current service issues, but also to move our fire- and life-safety systems into the 21st century.

Q. What are some of your team’s technical challenges?

A. One of the biggest technical obstacles is integrating multiple systems from various manufacturers so all systems function as a single unit. Staying current with ever-changing fire alarm technologies is also a challenge, so we work diligently with our equipment suppliers to identify trends to keep us current. We attempt to identify equipment that is nearing the end of its lifecycle so that we can upgrade to newer, more modern equipment.

An equally important issue is maintaining system integrity, which is paramount when you have multiple people working on the same system. In addition to our large staff, we have numerous vendors that work on our systems. Any time someone accesses our systems, we are responsible for ensuring the systems remain fully operational and that building occupants are safe at all times.

Q. What system features do you look for to meet those challenges?

A. It is important that the system is user-friendly; both school-based staff and maintenance personnel need to understand the life-safety systems. When we construct a new building at an existing campus, we might have to combine intelligent technology with hardwire technology, and it must appear seamless to the end user. We also have about eight to 10 networked fire-alarm systems and expect to install more of them. This technology seems to be the trend in the industry.

Q. Have Broward County Schools had any major fires?

A. We haven’t run into anything that we weren’t able to resolve with early detection. For example, there are certain areas of a building our systems cannot supervise through manpower or CCTV, such as restrooms. Actually, the highest fire incidents occur in restrooms because they are unsupervised by our systems. Based on this fire incident data, our safety department requires us to install detectors in all group restrooms with tamper-proof covers. We’ve had our group restroom incidents and end-of-year pranks, but we haven’t had any permanent damage to buildings, and nothing has gone undetected. We’ve been able to put out all small fires with minimal damage.

In fact, we’ve lost more time to hurricanes than any fire incident. When Hurricane Wilma hit (in 2005), Broward County looked like a war zone, but the schools were opened and occupied in less than two weeks. That’s a major accomplishment. Every fire-alarm system was checked and operable before students were permitted to return. We had to respond with, literally, truckloads of new batteries for the systems because the power had been out for several days.

Q. That must have taken a lot of time and energy to get back up to code, given the size of the district.

A. Due to the devastation that occurred countywide, there were many factors that needed to be addressed before the facilities could be reopened. The entire staff of physical plant operations came together and worked non-stop for 15 days until all buildings were deemed safe. I cannot say enough about all of the people who worked tirelessly until our district was re-opened and serving the community again.

Q. What are some of the ways your district exceeds code?

A. Being familiar with the tendencies of our students, we have installed pull station covers with sounders to deter any false alarms. In regard to notification appliances, System Sensor was instrumental in making the equipment vandal-resistant when we communicated our needs to them. We also put a smoke detector within 10 feet of all stoves that are in classrooms. It’s important for us to find new ways to become proactive. Exceeding minimum code is only one of those ways.

In addition to meeting NFPA guidelines, we developed a construction specification that includes other device requirements, and it is included in all new construction. One other way we exceed minimum code is by discontinuing the use of heat detectors and installing smoke detectors everywhere, except where environmentally prohibitive, which provides us with earlier detection.

Q. Are your fire systems integrated with other building systems, such as HVAC or security?

A. In regard to HVAC, we use general alarm control functions throughout all our buildings. We shut down all gas, air handlers, et cetera, on every alarm. We are, however, discussing more selective control. We have one high school with more than 5,000 students and four different buildings. We want to avoid releasing 5,000 students simultaneously due to security reasons and are looking into selective evacuation control with this particular facility. This has been approved by the local authority having jurisdiction in conjunction with our safety department.

Initially, there hasn’t been much integration of other building systems technologies, but as technology changes and bandwidth increases, we probably will include other systems, specifically security and CCTV. If Homeland Security puts a school in lock-down mode, and the fire-alarm system goes off, we are developing a process to follow. We need to refine and address this.

Q. Do schools in general receive the necessary resources to implement high-quality fire- and life-safety systems?

A. I know for a fact that Broward schools do. Our PPO management team and safety department are committed to ensuring the effectiveness of our systems – new and old. We are highly respected by neighboring school systems and have provided them direction on ways to improve their systems. As for Broward County schools, we are compliant in every way possible. We make repairs immediately and try to identify equipment that might become obsolete so that it can be upgraded before a critical failure occurs. There is no sense of avoidance on our part. We take whatever means necessary to exceed minimum code when possible. We have to protect a huge amount of property and people, and we all take it very seriously. Not repairing something related to fire safety is not an option.

Q. If you could offer one piece of advice to other districts, what would it be?

A. Establish and maintain strong relationships with manufacturers and their distributors. The equipment manufacturers are on the forefront of fire-alarm technology, and forging partnerships with them makes us better prepared to implement these new technologies. For example, we have been very well received by System Sensor and value that relationship. They help provide the resources we need to get the job done.

Photoelectric detection is preferred for several reasons, including:

1. Detection Capability — Photoelectric detection responds better to the larger smoke particles found in ductwork during a fire.
2. NFPA Recommends Photoelectric — The National Fire Alarm Code Standard 72, section A.5.14.4.2 explicitly states, “In almost every fire scenario in an air-handling system, the point of detection will be some distance from the fire source, therefore, the smoke will be cooler and more visible because of the growth of sub-micron particles into larger particles due to agglomeration and recombination. For these reasons, photoelectric detection technology has advantages over ionization detection technology in air duct system applications.”
3. Environmental Immunity — High humidity and condensation can cause false alarms with ionization detectors. Photoelectric detectors operate more efficiently, generating fewer false alarms.
4. Industry Preferred — Photoelectric detection is preferred by the fire alarm industry, manufacturers of commercial packaged air conditioning units and major retailers.
5. Low-Flow — Photoelectric detectors are capable of operating in air speeds as low as 100 feet-per-minute to meet new HVAC applications and codes with variable air volume systems and fire smoke dampers.

Can I interconnect more than 10 Innovair (4-wire, conventional) duct smoke detectors?

Absolutely. Refer to, Interconnecting more than 10 Innovair 4-Wire Conventional Duct Smoke Detectors, on System Sensor’s website (www.systemsensor.com) under Technical Field Bulletins for the simple, two-step connection method.

What is the best procedure for testing System Sensor duct-mounted smoke detectors?

There are four simple steps to test System Sensor’s duct-mounted smoke detectors:

1. Verify the detector is installed per NFPA 72 guidelines and is in accordance with the manufacturer’s installation instructions.
2. Employ the detector’s built-in test feature, such as the test magnet or accessory test switch. These features are designed to meet NFPA and Underwriters Laboratories functional test requirements that ensure the detectors are operable and will respond to minimum smoke requirements.
3. Measure the pressure differential across the sampling tubes (exhaust and intake) with a manometer to ensure the detector will respond to smoke in the duct airflow. This is the manufacturer’s acceptable test.
4. Apply smoke directly to the detector head to initiate an alarm. The sampling tubes may need to be blocked off for this test and then reopened afterwards.

Why is a smoke bomb test not recommended for ionization duct smoke detectors?

Based on evidence with in-house and field-testing of ionization, duct-mounted smoke detectors, there are three notable reasons:

1. Ionization smoke detectors are most sensitive to smoke particles ranging from .01 to .3 microns. Particles produced by smoke bombs tend to become larger the farther they travel from the source, triggering a slow response.
2. Smoke bombs produce cold smoke particles, which are larger and not as easily detected by ionization smoke detectors. These particles are also dependent on relative humidity, distance traveled from the source and time of activation. This phenomenon is caused because the smoke is more of a mist than suspended solids in warm gases. In other words, the smoke doesn’t represent a true smoke composition or fire signature for smoke detector activation.
3. It is possible to pass a smoke bomb test, but to be out of the required manometer range for sampling, giving the installer a false sense of proper operation.

Although unadvisable, if you choose to conduct a smoke bomb test, use a photoelectric smoke detector, which typically responds to smoke particles between .3 and 10 microns, and, if you have a respiratory ailment, use a self-contained breathing apparatus.

Where can a System Sensor duct-mounted smoke detector be installed in relation to the duct?

System Sensor duct-mounted detectors can be installed horizontally and vertically to — and on top of, within and underneath — the duct. However, we do not recommend installing underneath the duct because condensation may drain into the electronic circuitry and cause electrical damage.

To determine the best location, System Sensor recommends comparing the pressure differential between the sampling and exhaust tube. The pressure differential must be within specified limits of .0015 to 1.20 inches/water for photoelectric smoke detectors. The detector housing cover must be securely fastened to complete the airtight enclosure for proper air sampling and to restrict contaminants from entering the detector head.

In order to shut down the HVAC system, what do I connect my HVAC or RTU (Roof Top Unit) to?

To provide immediate shutdown during an alarm, connect to the controller voltage from the RTU. Connecting to the thermostat will only allow a gradual shutdown of the HVAC system. In some cases, the RTU manufacturer requires a shutdown of this type because, if stopped too fast, the bearings could become damaged. Be sure to review each situation accurately.

Can System Sensor test stations and other accessories be used with duct smoke detectors manufactured by other companies?

No. They are not compatible due to a different electrical makeup. This includes the SSK451 Multi-Signaling Device, which features:

1. An audible and visible alarm annunciation.
2. A key activated test and reset functions.
3. Green, amber and red LEDs that provide visual indication of power, trouble and alarm indications.
4. An optional snap-on smoke strobe.

The proper installation of duct smoke detectors is critical to preventing the transfer of smoke and other toxic gases during a fire. Unlike standard smoke detectors that are set up by a single installer, heating/ventilation/air conditioning (HVAC)-contaminant monitors can be set up by installers of various trades, making communication imperative.

Installers of at least four crafts may be involved in a duct smoke-detector installation, including an air conditioning or roof top unit (RTU) installer; a mechanical contractor responsible for duct work; an electrician for handling high-voltage wiring and conduit; and a technician who installs the building control panel.

“Traditionally, it goes by union guidelines,” says Chuck Harding, general manager and founder of Harding Heating in Schaumburg, Ill. “Sheet metal workers do the duct work. So, they connect the smoke detector to the HVAC system. The electricians then provide the power. Those are the traditional jurisdiction lines that are pretty much defined throughout the country, as far as the unions are concerned.”

However, Harding has seen jobs during 20 years of running his own business that were not as traditional. “I’ve also seen each one of the crafts do the entire job by themselves. It just depends on who is on the job. You can’t always assume that all the crafts are involved. If it is a smaller job, it’s not uncommon for the HVAC guy to do it all.”

Which Code Authorities Prevail?

The importance of top-down communication can also be critical in making sure a job follows the strict body of laws that govern it. But, sometimes the installers are unaware of which code prevails: national or local. Therefore, communicating the certified code of the Authority Having Jurisdiction (AHJ) is a critical first step for every installer.

For example, installation may be originated by the ductwork installer or the RTU installer. However, if the voltage to power the detector is 120 VAC, in accordance to the National Electrical Code, an electrician must install the conduit and run the wire. Who, then, is responsible for connecting the RTU to the auxiliary relays for shutdown during a fire?

“Fortunately, in larger jobs, this is normally written in the specification,” explains Harding. “The engineer’s orders tell you who is the authority having jurisdiction. These are written commonly in a way that identifies such-and-such trade will provide ‘X’ service, while another provides different service. A lot of it depends on the detector; some are high voltage, some are low voltage. Again, it all comes back to the engineer’s order, but I have seen it where the owner dictates this. Some dictate a lot on a job.”

Knowing who the AHJ is, therefore, must be relayed to the installers for each job. Companies like Harding Heating, which take on jobs in Illinois, Wisconsin and Indiana, have to be aware of the many different codes that may be applicable.

“It’s village-to-village and depends on the authority having jurisdiction,” says Harding. “Some villages have more emphasis on some things than others do. For duct smoke detectors in particular, the Building Officials and Code Administrators code says they must be installed in buildings that have 2,000 cubic feet of airflow per minute. But, some village codes exceed this; some don’t. Just like some have remote testing requirements and others don’t. It makes communication very important.”

Another code-adherence tip Harding offers is to make sure the duct smoke detector’s installation paperwork is handed down the line to the craftsmen who will handle the final phases of installation, as is required by national code. “Passing off the installation manual is a must. We leave it in the detector,” says Harding. “But, somewhere down the line, someone takes it or does not think to leave it for the next guy. It’s not intentional, but it is a violation of the code.”

Start-up and Maintenance

System Sensor smoke detectors are designed to be as maintenance-free as possible. However, due to the environment they are in, dust, dirt and other foreign matter can accumulate inside detectors, changing the level of sensitivity. This is especially true with duct smoke detectors. More sensitivity results in unwanted alarms. Less sensitivity results in reduced protection. Both cases are undesirable. Detectors should be tested periodically and maintained at regular intervals (see “Typical Testing Procedures for Duct-Type Smoke Detectors”).

“I always tell my customers to follow a stringent testing program,” says Harding. “Of course, they work the first day, but what about three years down the road? You have to follow the maintenance procedures set out by the manufacturer, as well as the code. Remember, the building code is there for a purpose: It is the minimum for safety. It is not to be violated or ignored for installation or maintenance.”