Assuring Burg/Fire Panels Are a Winning Combo

The act of integration where it involves fire and intrusion detection can be a good thing. For instance, it will almost always result in more information being available at a single location. The value to operators who routinely make decisions cannot be overemphasized, especially when the speed and quality of a decision can mean the difference of life and death.

Section of NFPA 72, 2007, offers a host of ways that fire alarm systems can be integrated with nonfire systems. In brief, they include a dry set of contacts, data over a signaling line circuit (SLC), and any other method tested and listed by a third-party testing/listing organization, such as UL of Northbrook, Ill.

Additional technical help on the sharing of a fire alarm control system with other nonfire functions is covered in Section 6.8.4, titled “Combination Systems.”

According to Subsection, NFPA 72, 2007, “Fire alarm systems shall be permitted to share components, equipment, circuitry, and installation wiring with non-fire alarm systems.” The bottom line, as cited in Subsection, is that this action must not jeopardize fire/life-safety functions of the fire alarm system itself in any way.

The SLC is the heart of most modern-day fire alarm systems. The use of combination devices that either hold a dual-use or a single nonfire use is permitted, providing it complies with code.

In this case, we must refer to Section 3.3.173 for a working definition of a SLC. “A circuit path between any combination of addressable appliances or devices, circuit interfaces, control units, or transmitters over which multiple system input signals or output signals or both are carried.”

Cabling Choices Can Be Critical

The SLC is specifically designed for the flow of data between an alarm control panel and a variety of devices, such as manual fire pulls, smoke detectors and more. Because digitized data will flow over it, special care must be exercised by the installer to assure that the correct wire is used on the job.

Although the engineer on the job should arbitrarily see that the correct wire is ordered and delivered to the job in the first place, it’s the installer who holds a fire license of some kind that ultimately must take responsibility for what is installed on the job. If the wire is wrong, it’s your job to tell the project manager or sales engineer who specified and ordered it.

Fire alarm panels like those made by Silent Knight, a Honeywell company, will work on just about any kind of cable. But there are other control panels that require specific kinds of cable before their system will work properly.
The MaxSys system by DSC (Digital Security Controls), for instance, i
s specifically designed for conductors that twist ever so slightly in a global manner, and only up to size 18 AWG. Any other type or larger size conductor can jeopardize the functionality of the system.

Electrical contractors, for example, may look at a bid specification and arbitrarily substitute a shielded cable for a specified nonshielded cable. Their rationale is that adding a shield improves noise reduction, which may be true in certain instances. But where it involves DSC and several other makers, it actually reduces the effective amount of cable that can be installed.

Some panels, like MaxSys, offer power over the same two conductors that carry data. Others, such as Honeywell’s Vista, require a separate set of conductors for power and data.
Where there’s a danger of interference between fire and burglar alarm devices, it’s also advisable to use isolation modules. Isolation modules are designed to separate devices and functions on the same SLC.

Be sure to study the specifications of the combination fire/burglar alarm panel you use before roughing in the cable.

Al Colombo is an award-winning writer who has covered electronic security and life safety since 1986. To reach Al, visit or E-mail [email protected].

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About the Author


Al Colombo is a long-time trade journalist and professional in the security and life-safety markets. His work includes more than 40 years in security and life-safety as an installer, salesman, service tech, trade journalist, project manager,and an operations manager. You can contact Colombo through TpromoCom, a consultancy agency based in Canton, Ohio, by emailing [email protected], call 330-956-9003, visit www.Tpromo.Com.

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