Staying Ahead of the Flame Game

Higher Level of System Intelligence

A leading trend affecting the life-safety landscape is the general move toward a more advanced, intelligent fire alarm platform, one in which a greater degree of integration, incident details and processing speeds are attainable. The alarm information provided by a typical conventional fire alarm panel is by zone rather than device. An activated smoke detector, for example, will only provide the affected zone, which correlates to a general area or floor. A digital-based addressable system, however, will provide the exact location of the smoke detector involved.

For this reason, more and more fire alarm companies are promoting addressable fire alarm systems. What was once seen as a hard sell is now becoming commonplace as technology-savvy clients seek the powerful features that addressable systems bring to the table. This is especially true of larger buildings where integration combined with advanced intelligence-gathering capabilities is realized.

According to recent research by SSI, more than half of all security contractors are presently installing addressable fire detection solutions, as well as integrated fire/life-safety systems. Other advanced technologies gaining traction in the marketplace include wireless fire detection devices and carbon monoxide detection systems (both deployed by 45 percent of installing companies). However, by a substantial margin, contractors are most intrigued by wireless’ potential, followed by addressability.

Today’s intelligent fire alarm systems turn on advanced data processing, utilizing even more analog information than was available a few years ago. This is especially true of a relatively new breed of addressable technology that most of us have come to know as analog addressable. The analog addressable systems are more high-tech than the simple digital addressable systems. Digital addressable can only identify the location and identity of the device. Analog addressable will do the same with the addition of analog data that rides on the digital data. Analog addressable is a newer, more advanced version of the simple digital addressable. 

Power of Analog Addressability

The advent of the digital-based addressable fire al
arm system has been a great boon to both consumers and fire alarm companies. When you compare these new systems with the conventional systems of yesterday, there is no denying that it has had a great impact.ince the release of the first digital addressable systems, the industry has been moving at breakneck speed toward an analog solution that brings digital processing and advanced multiplex signaling techniques together. The objective here has been to render an even more powerful fire detection platform that’s capable of collecting and displaying even more information — and doing so faster and more effectively than the earlier digital addressable systems ever could.

According to Blue Springs, Mo.-based Fike Corp.‘s Web site, “Today’s advancements have lead to fire alarm systems being more capable of collecting and reporting information than was available in years past. In intelligent systems, each initiating device individually reports to the central processing unit (CPU) within the fire panel. In addition to knowing which sensor it is, the intelligent fire panel can tell you the sensitivity of a smoke detector, its location and the ambient temperature in the vicinity of the detector.”

Today’s high-tech fire panels can individually monitor each sensor, such as analog addressable heat and smoke detectors. Smoke detector heads are monitored for their sensitivity rating. Not only that, but these modern marvels can also adjust smoke detector sensitivity when known changes occur in the environment.

For example, in a manufacturing plant it may be prudent to adjust the overall sensitivity of smoke detectors in certain areas where there is excessive dust and other airborne particles. Once the risk is over, the alarm panel will return these smoke detectors to their proper sensitivity.

Smoke detector sensitivity also can be adjusted according to day/night and holiday scheduling in accordance with known risks. And when an alarm is detected through a feature called “alarm verification,” these systems can be prompted to reset the target detector, awaiting reactivation within 60 seconds. At that time the system will sound the alarm throughout the affected area. 

Central Station Reporting

The advent of the digital communicator in burglar alarm systems during the 1970s resulted in swift adoption for fire alarm monitoring. NFPA allows several ways for signals to travel from fire alarm panel to central station; the common telephone line is just one of several methods.

For decades, fire technicians have grown accustomed to using a digital alarm communicator transmitter (DACT) with two metallic phone lines to send supervisory and alarm signals to a central station. This is done using the Public Switched Telephone Network (PSTN), also referred to as Plain Old Telephone Service (POTS).

One of the problems with the DACT arrangement is the number of requirements imposed on the fire alarm installer. And as we shall see, there are very good reasons for doing so. At the head of the DACT is a supervised telephone line switcher that is designed to monitor each phone line for proper on-hook voltage. When this voltage dips below a certain level, or if it should disappear altogether, the switcher is required to move the DACT to a second phone line.

“A DACT shall be connected to two separate means of transmission at the protected premises. The DACT shall be capable of selecting the operable means of transmission in the event of failure of the other means” (Sections 8.6.3.2.1.5(4) and 8.6.3.2.1.5(5), NFPA 72, 2007 Edition).

When one of the two signal paths is disrupted, the switcher is required to issue a supervisory condition, which is to render a local indication at the fire annunciator/keypad as well as the central station – assuming the second phone line is still intact.

Not only does code require the use of a supervised switcher with two phone lines, it also requires the use of two separate phone numbers, one for primary reporting and another for secondary. This, of course, is a function of the software programming the fire alarm tech invokes within the code-compliant fire alarm panel.

For example, according to Section 8.6.3.2.1.5(5) of NFPA 72, 2007, “Each DACT shall be programmed to call a second DACT line (number) when the signal transmission sequence to the first called line (number) is unsuccessful.”

Probably the best way to deal with this is to use the central station’s toll-free receiver number as well as the direct toll number. The toll-free number can be used on the first attempt and the toll number on the second try. 

Advances Bring Changes in Code

Veteran fire alarm technicians are sure to recognize many of the long-time signaling technologies used in fire alarm signal transport. Some of them include active multiplex signal transmission, McCulloh loop, two-way radio frequency (RF), one-way private radio, directly connected non-coded systems, as well as digital communications. The truth of the matter is recent technological changes have had an impact on code in addition to how fire alarm technicians do their jobs.

For example, Section 8.6.3.2.1.4 of NFPA 72, 2007, provides a master menu of high-tech signaling methods that can be used as a secondary signal path in conjunction with PSTN. Many of these signaling means have been around for some time while others are relatively new. The code eventually had to be adjusted in order to adequately address the new communication technologies that have emerged through the years, and it will continue to do so in the future.

Section 8.6.4, “Other Transmission Technologies,” addresses this issue by allowing for alternate methods employing technologies that lend themselves to redundancy and supervision.

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