Tenable Environment: An environment in which smoke and heat are limited or otherwise restricted to
maintain the impact on occupants to a level that is not life threatening. The principle objective of a
smoke control system is to maintain a tenable environment longer than the required safe egress time.
Smoke control methods are often defined as active or passive systems. • An active smoke control system
uses mechanical equipment to control the spread of smoke in a structure. It includes pressurization
method, airflow method and exhaust method. • A passive smoke control system uses building
construction materials to limit the spread of smoke in a structure. Typical passive smoke control systems
include compartmentation, fire rated walls, barriers, smoke vents, shafts etc.