What is in this article?:
On most college and university campuses, the fire-alarm setup typically comprises either a number of standalone building fire-alarm systems of various vintages, or an outmoded, inefficient hardwired monitoring system. In either case, upgrading the fire-safety system to a modern addressable campuswide system will increase its speed, reduce response time and improve maintenance. As a result, an institution will benefit from enhanced life safety and property protection, and reduced liability.
A number of cost-effective approaches are available for upgrading an existing system to a campuswide addressable network. Mapping out the best route requires an understanding of the existing technology and campus infrastructure, the campus master plan, and the codes and standards that apply in the local jurisdiction.
From standalone to street-box systems
The majority of campuses have a collection of protected-premises (local) fire-alarm systems — standalone units designed to protect a single structure — that were installed as buildings were built or acquired. In some cases, these have been hardwired into a campuswide monitoring system.
These older systems use a McCulloh circuit, a campuswide loop of standard, high-voltage paired copper wire cable that runs either underground or overhead, connecting all of the protected-premises fire-alarm systems to one monitoring system. McCulloh circuits operate on a principle similar to the old municipal fire-alarm systems, also known as street-box systems, in which each pull box in the system generates a series of audible rings whose pattern identifies the street box or building in which the alarm is sounding.
In the mid-1970s, the introduction of low-voltage multiplex technology improved the communications capabilities of campuswide fire-alarm systems. Nevertheless, the multiplex systems remain relatively slow, and, like the original protected-premises and hardwired monitoring systems, they cannot pinpoint the source of an alarm.
Many of the older, inefficient field devices also are still in place. This inevitably means response delays. Moreover, these systems are becoming increasingly difficult to maintain as manufacturer support and replacement parts become scarce.
