It’s Here!

IP fire alarm communications


 

Overline: MARKET FOCUS

By Dave Miller SET

Head: 

It’s Here!

Deck: 

Convergence in fire alarm and IP technology has arrived

For nearly a decade, the security industry has been using the term “convergence” to describe the merging spheres of physical security and IT infrastructure and systems. The fire alarm industry has until recently remained relatively untouched by convergence.

Code changes to the 2007 National Fire Protection Association’s National Fire Alarm Code[i] (NFPA 72) have addressed this issue, and manufacturers are beginning to introduce products that can comply with NFPA 72’s alternative means of communication.[ii]

In the last 20-plus years the primary means of communicating the status of a fire alarm system to a receiving station has been a POTS (plain old telephone system) line with the following approved means for secondary notification:[iii]

  • A second phone line
  • Cellular telephone connection
  • One-way radio system
  • One-way private radio alarm system
  • Private microwave radio system
  • Two-way RF multiplex system

The de facto standard in much of the U.S. has been to use POTS lines for both primary and secondary notification. In many jurisdictions this has come to mean two “dedicated” POTS lines.

There has been ample confusion about whether the lines need to be dedicated. NFPA 72 basically makes the following requirements.[1]

  1. The lines are under the control of the subscriber.
  2. The fire alarm system has the ability to seize the POTS line ahead of other functions on the line.
  3. Dial tone is immediately available when going off-hook.

A good example of whether the lines should be dedicated is found in a multi-tenant building application.

In the first variation of the example, the owner of the building has a management office in the building, and they have two POTS lines for voice and fax service, thus the lines are under the control of the subscriber. These two lines can be used for fire system communications as shown in Illustration #1 and where the lines are configured to meet requirements 2 and 3 above.

Illustration #1: Standard 2-Line POTS/DACT Configuration

In the second variation of the example, the building owner does not have offices in the subject property, and the building owner is furnishing the monitoring of the fire alarm system. In this case, two dedicated POTS lines would be required for the system monitoring.

There are a myriad of possible variances to the above examples and the requirements of the AHJ must be factored in as well.

IP fire alarm communicators

Section 8.6.4 of NFPA 72–2007 allows for “Other Transmission Technologies.” Many of the fire alarm manufacturers are now beginning to offer Internet protocol (IP) communicators that are listed to the requirements found in 8.6.4. Initial versions of the IP “communicators” had a requirement that a POTS line be associated as the secondary means of communication to the receiving station. The latest versions now operate as an IP only device.

A primary concern about an IP communicator, with no other alternative communication path, is that while they will be designed to have a battery backup for 24 hours or more, how can it be ensured that the data equipment upstream, i.e., switches, routers and gateways up to the demarcation point, have the same level of emergency backup? Uninterruptible Power Supply (UPS) cost for all data switch locations and the ISP equipment can be expensive both for initial cost and ongoing maintenance.

In a long power outage, if the data equipment does not have 24 hour or longer emergency power to the IT equipment, it cannot be ensured that a fire signal will be transmitted to the Central Station when primary power is interrupted. During the primary power outage, if properly installed, the system will notify the owner at the site with a trouble signal and the receiving station will call to notify the system owner of the drop in service.

There are some practical steps that can be incorporated to help minimize this issue and the risk to the monitoring provider:[iv]

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