Smoking and Its Control

Practical Applications of Smoke-Control Systems

Two basic design methods to help prevent smoke migration and maintain a tenable environment for occupants

Design criteria for smoke-control systems have changed over the years. Instead of ventilating an affected area, smoke-control systems now must prevent the spread of smoke to non-affected areas and/or provide a tenable environment in the area of incident. How effective are current smoke-control systems? Can building-code requirements for smoke-control systems be met reasonably? How can applications not described in building codes be addressed?

Smoke-control-system requirements have been in place for years, and smoke-control-system design has had to adapt to building-code-requirement changes. This article will address some practical design applications of these systems as well as how building-code requirements can be applied. The article also will address ways to adapt a design to meet building-code intent.

HISTORY OF SMOKE-CONTROL REQUIREMENTS

Smoke-control systems have been utilized in high-rise buildings since the mid-1970s. In early building codes, mechanical systems were required to provide a specific exhaust rate to ventilate a space; building codes later required specific air-change rates, typically six air changes per hour (ACH).The 1994 edition of the Uniform Building Code (UBC) required smoke-control systems to be designed using a performance-based approach according to one of four basic design methods: pressurization, passive, airflow, and exhaust. These methods were tied to National Fire Protection Association (NFPA) standards for smoke-control systems. Design criteria for the pressurization, passive, and airflow methods included maintaining smoke in the zone of origin to prevent its spread throughout a building; the exhaust method's criteria included maintaining the smoke layer above the highest walking surface in an effort to maintain a tenable environment. Since the adoption of the 1994 UBC,...