ch12 smoke control and management systems

Chapter 12Smoke Control and Management Systems

Objectives• Define the terms smoke control and

smoke management.• State the design goals for smoke control

and smoke management systems. • Name the three general methods used to

control smoke movement.

Objectives

• Describe the four pressure differential methods used to control smoke.

• Describe five design requirements or operational characteristics of smoke control systems.

Objectives• List the different life safety and fire

protection systems that interface with smoke control systems and describe how they interact.

• Discuss the importance of the acceptance testing and annual retesting of smoke control and management systems.

Introduction• Smoke and toxic gases migrate outside

the fire area and through a structure during a fire.– Can cause as much damage as burns– Exposed areas: stairways, corridors, elevator

hoistways, atriums, openings in walls, etc.

Introduction• Smoke control: mechanical systems that

pressurize areas of buildings with fans to limit smoke movement

• Smoke management: passive and active systems used alone or together to alter smoke movement

• Smoke management creates a tenable environment for occupants and fire fighters; systems were developed in the 1970s.

Introduction• Passive design

approach– Uses walls, bulkheads,

doors, partitions, draft curtains, high ceilings, and sealed floor openings to create barriers

– Fire-rated construction

© A. Maurice Jones, Jr./Jones & Bartlett Learning

Introduction• Active design approach

– Focus of this chapter– Uses mechanical systems to exhaust,

pressurize, and oppose smoke with forced air• Choice of design (passive, active,

combination) depends on many factors.

Introduction• Physical design and architectural features of

structures facilitate smoke movement.– Obvious: stairways, elevators, airshafts, ductwork– Less obvious: unsealed construction and space,

etc.• Smoke spread also depends on many factors.

– Buoyancy forces, stack effect, climate, ventilation and HVAC, fuel load, etc.

Code-Required Smoke Control and Smoke Management

• Code-mandated installation is limited to certain kinds of structures and occupancy classifications.– Design of some buildings facilitates easy

evacuation, inhibits smoke movement, and includes fire protection systems.

– Smoke control systems are required for high-rises, atriums, covered malls, underground buildings, stages, platforms, correctional facilities, etc.

Smoke Containment, Removal, and Opposed Airflow

• Goal is to maintain tenability by mitigating smoke spread or containing it.

• Systems can be stand-alone or integrated.• 100% outside air for positive pressurization

and smoke relief systems; 100% exhaust to the outdoors to contain/relieve smoke

• Methods: containment, removal, opposed airflow

• Containment by pressure differentials– Pressure differentials between affected and

unaffected areas help with smoke control.• Low pressure differentials reduce/contain smoke.• Pressurization is one of the most common

methods of smoke control.• Model building codes, standards, and publications

outline design requirements (NFPA 92, 92A, 92B and publications from ASHRAE).


• Stairway pressurization systems– Prevent/reduce smoke

intrusion into egress stairways

– Mechanical fans pump outdoor air in and create a pressure barrier.



• Stairway pressurization systems (cont’d)– Work well when combined with smoke

removal/relief on affected floors– Many design considerations affect

performance.– Common in high-rise buildings


• Floating zone/floor-by-floor pressurization– “Sandwich effect” or

“containment method”– Uses HVAC to create

negative pressure on fire floors; applies positive pressure above and below



• Floating zone/floor-by-floor pressurization (cont’d)– Used in high-rises in addition to stairway

systems– Smoke-laden air is removed; outside air flows

in.– Air moves from high to low pressure.


• Elevator hoistway pressurization systems– Similar to stairway systems– Mechanical fans pump outside air into hoistway

and create a pressure barrier to smoke.– Some designers think they should be part of

complete smoke management system for adequate pressurization.

– Others are concerned about elevator doors being open.


• Refuge area pressurization– Refuge areas are

usually located on each floor of a high-rise, near stairways, or near elevator lobbies.



• Refuge areas– Constructed with fire-rated materials and self-

closing fire-rated doors– Holding areas for people who need

assistance– Typically combined with elevator hoistway or

stairway pressurization


• Smoke removal– Best suited for large volume spaces where

smoke and toxic gas flow freely– Systems can help create a tenable environment

in egress corridors, elevator lobbies, and refuge areas.

– Lack of restriction causes other problems in addition to large amounts of smoke and gas (e.g., delayed activation of sprinklers and detectors).


• Smoke removal (cont’d)– Unpolluted air from a

lower level is fed up at a slower rate than the exhaust system rate.

– Enables one or more mechanical fans near the upper level to exhaust the smoke



• Containment by airflow direction– Can control smoke across openings when

pressure differential strategies are impractical– Common for fires in railway, subway, or

vehicle tunnels– Least common strategy for containment

because of the complex control and necessary large air volumes

• Risk of feeding the fire


Design Requirements and Operational Characteristics

• Design is challenging due to the uniqueness of environments.– Important to know the requirements of

adopted model codes and standards– Model codes include a variety of operational

requirements.

Fire Protection Systems and Smoke Control

• Without automatic or manual detection and suppression, smoke control systems may be overwhelmed by fire.

• Proper operation of detection and automatic sprinkler systems, plus fire fighter response, is key to controlling smoke and gas.

• Interface with fire protection systems and other life safety systems– Smoke control and management systems

interface with fire protection, HVAC, elevator, and backup power systems.

– During design, smoke control zones, sprinkler zones, and detection zones are coordinated.

– Activation of automatic initiating device usually prompts operation of smoke control systems.



• Interface with fire protection systems and other life safety systems (cont’d)– If HVAC systems fail to shut down, this can be

the strongest contributor to smoke movement (usually coordinate well with other systems).

– Smoke detectors in elevator lobbies interface with elevator systems to establish recall priorities.

– Smoke control systems require both normal and emergency power sources.


• Interface with fire protection systems and other life safety systems (cont’d)– Functional components of smoke control

systems require monitoring.– Must have operational controls for each

smoke zone


• Interface with fire protection systems and other life safety systems (cont’d)– Smoke control panel

must have status indication and control function to show location of all major systems.

(c) Pete Mensinger

Testing and Performance Verification

• Acceptance testing– Design professionals develop detailed test

plans.– Testing occurs after all other life safety and

fire protection systems are tested and approved.

– Testing is similar to other fire protection systems’ tests.


• Acceptance testing (cont’d)– Functional and integrated performance testing:

• System response time• Air pressure differential• Door opening forces

– Artificial smoke/fog can give visual confirmation of performance but is not an actual representation.

– All final tests must be witnessed and documented.


• Acceptance testing (cont’d)– Smoke control systems must undergo annual

functional and performance retesting to avoid disrepair.

• Required by many state and local jurisdictions• Addresses individual components and integrated

performance• Similar procedures to acceptance testing• Some tests performed by owner’s personnel, some

by individuals who did initial testing

Summary • Smoke control and management systems can

provide a tenable environment or contain smoke in the area of origin so occupants can exit a building and fire fighters can move or stage during a fire incident.

• The three general methods of smoke control are containment, exhaust, or opposed airflow; the choice greatly depends on physical design and architectural features of the building.

Summary• Containment is the most commonly used

method of smoke control and depends on establishing pressure differentials between the protected area and the fire area.

• Typical pressure differential methods include stairway pressurization, floating zone or floor-by-floor pressurization, elevator hoistway pressurization, and refuge area pressurization.

Summary• Smoke removal is common for large volume

spaces, but opposed airflow is another option to prevent smoke and gas from flowing through large unprotected openings.

• In order to ensure appropriate system-wide operation, it is extremely important that smoke control systems are interconnected with fire protection systems, HVAC systems, elevator systems, and backup power systems.

Summary• The design of smoke control and smoke

management systems offers the design professional many challenges, but a well-designed, installed, and maintained system will provide building occupants and fire fighters the tenable environment necessary to evacuate, relocate, or stage during a fire emergency.

Summary• Acceptance testing and annual retesting

verifies the system performs as designed and is based on a detailed test plan that provides the description of the smoke control system, the design criteria, how these criteria will be demonstrated and proven, what will constitute successful performance, the step-by-step procedures, and the test instrumentation and equipment used.

ch12 smoke control and management systems

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