Fire Protection Engineering

Fire Protection Engineering

Fire Detection System

Introduction

Over the last several years, great strides have been made in the application of fire engineering. This has been facilitated in part by the development of codes and guidelines for the application of performance-based analysis and design of buildings and structures. Within the performance-based analysis and design process, various fire and life safety systems and features exist that may be incorporated into trial design(s), including fire detection systems. Fire detection systems serve multiple purposes, including monitoring other devices and systems, detecting products of combustion, activating smoke management and other systems, notifying people that there is an emergency, and summoning emergency responders (see Figure 1) (Benjamin, 2005).

Figure 1 - Overview of Functions of a Fire Alarm Control Unit

Smoke detection

Smoke detection has become a fundamental component of the active fire protection strategy of most modern buildings, particularly residential occupancies. However, this was not always the case. The smoke detection industry experienced explosive growth in the use of smoke detectors in the 1970's, driven by advances in technology and manufacturing that greatly reduced prices. This explosive growth was accompanied, and likely furthered, by several significant research projects that reinforced the life safety protection provided by smoke detector and provided evidence that supported increased requirements for smoke detectors in buildings. In addition, significant research efforts were undertaken to und Smoke detection has become a fundamental component of the active fire protection strategy of most modern buildings, particularly residential occupancies (Benjamin, 2005).

However, this was not always the case. The smoke detection industry experienced explosive growth in the use of smoke detectors in the 1970's, driven by advances in technology and manufacturing that greatly reduced prices. This explosive growth was accompanied, and likely furthered, by several significant research projects that reinforced the life safety protection provided by smoke detector and provided evidence that supported increased requirements for smoke detectors in buildings. In addition, significant research efforts were undertaken to understand the environments to which detectors are exposed and the response of these detectors to such environments. Many of the means by which to estimate the response of smoke detectors were formulated during this period of important smoke detection research (1970's) and have not advanced significantly since then; they are still the only available means for engineers to even approximate the response of smoke detectors (Harrison, 2003).

The main objective of most fire detection and alarm signaling systems is detecting a fire early so as to initiate various actions. Being able to adequately assess the time when an initiating device may activate is therefore important, especially when undertaking a performance-based assessment and the overall development of a fire safety strategy. NFPA 72 contains information to assist in designing a detection system prescriptively. In addition, over the last several revision cycles, efforts have been made to help better address detection systems in the performance-based analysis and design process. These are reflected in 'Annex B - Engineering Guide for Automatic Fire Detector Spacing'. This Annex has continued to build upon the work ...