The Need for Smoke Control Systems
Studies have shown that smoke emitted by fires are just as fatal, if not more, than burns. This is because the smoke contains toxic gases, its heat causes burns inside the lungs, and obstructs the visibility of occupants. All these issues caused by smoke result in a slower egress speed and longer time for occupants to get to safety. Fortunately, smoke control systems have been developed to combat these issues and help occupants avoid smoke to get safety.
What is a Smoke Control System?
Smoke control systems are systems that control the movements of the smoke in a building in the event of a fire. These systems can be a part of an existing HVAC system, or it can be a standalone system. Although these systems can vary based on components, methods, location, and situation, the concept of maintaining a manageable smoke environment long enough for occupants to exit is the same.
Types of Smoke Control Systems
There are two categories under smoke control systems, which include smoke containment systems and smoke management systems. Smoke containment systems are used to prevent smoke from entering certain areas through pressurization, like stairwells for example. These systems work through pressurizing one area, causing the pressure difference to prevent smoke from entering into that certain area, which can be seen below:
A few types of smoke containment systems that are used for smaller enclosed spaces are as follows:
· Stairwell Pressurization
· Zone Smoke Control
· Smoke Refuge Area Pressurization
· Vestibule Pressurization
· Elevator Pressurization
Smoke management systems on the other hand tend to maintain the smoke in larger areas for the purpose of egress and prevent the smoke from migrating into surrounding areas. These types of systems operate through natural ventilation that removes the smoke, with the help of an exhaust fan that moves the smoke out of the building. Once the smoke is out of the building, makeup air must be entered into the large space to replace the air lost through the ventilation. Otherwise, the pressure that builds up can become problematic. This process can be seen through the visual below:
The end goal of these types of systems is to keep the smoke above the occupancy level for safe egress. A few types of smoke management systems that are used for larger spaces are as follows:
· Mechanical Smoke Exhaust
· Natural Smoke Ventilation
RAN’s Experience with Smoke Control Systems
Over the course of our operation, RAN has performed many smoke control projects. As a result, we have become proficient, knowledgeable, and experienced in this area of fire protection engineering. We have designed both smoke containment and management systems for a variety of markets, as well as incorporated these systems into new and existing buildings.
To demonstrate our expertise in smoke control systems, Samantha Wile and Gillian Nadeau gave a presentation at the SFPE 23 Annual Conference & Expo on Smoke Control Systems. If you were unable to attend the conference, you can find two project examples below briefly showing our experience.
RAN’s Project Examples:
Rochester General Hospital Atrium
Rochester, NY
It was discovered early within the design phase that the application of the prescriptive building code requirements would result in a “wind tunnel” condition within the atrium. The prescriptive building code requirements would also result in the expensive installation of equipment that would not meet the intent of the code. A report was generated which outlined the preliminary code analysis, criteria for the design fire, and exhaust rate. The report summarized the basic design criteria for the smoke management system which was used to evaluate system design options. The final design incorporated application performance-based criteria for the smoke management system specific to the building conditions. It resulted in a 50% cost savings and a functional smoke.
ORDA Whiteface Base Lodge Stairwell Modernization Project
Wilmington, NY
RAN Fire Protection Engineering was retained for
the design of fire sprinkler, standpipe, and fire alarm for the main entrance and interior stairwell modifications to the Whiteface Base Lodge in Wilmington, NY. The design worked with the unique building floor plan, increased in difficulty given the constraints of the Variance utilized under the original construction of the building. Additionally, RAN developed a Code Path and layout for the interior stairwell utilizing automatic accordion smoke and fire doors which allowed the open interior stairwell to be defined as an enclosed stairwell. The enclosed stairwell re-classification allowed for the omission of an atrium smoke control system, resulting in a construction cost savings of several hundred thousand dollars.