Chapter 12 Challenging Questions

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Old Dominion University *

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Mechanical Engineering

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Dec 6, 2023

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1. What is the difference between a smoke control system and a smoke management system?  Smoke Control: mechanical system that pressurizes areas of buildings with fans to limit smoke movement  Smoke Management: passive or active systems used alone or in combination to alter smoke movement 2. What are the design goals behind installing smoke control or management systems? To provide a tenable environment for occupants and firefighters. Allow tenants a safe environment for escape. Allow safe environment to facilitate fire department operations 3. What are the differences between the containment, exhaust, and opposed airflow methods of smoke control? 1. Containment is the most commonly used method of smoke control and depends on establishing pressure differentials between the protected area and the fire area 2. Exhaust 3. Opposed airflow is another option to prevent smoke and gas from flowing through large unprotected openings such as those that would lead into an atrium 4. Compare and contrast the four pressure differential methods used to control smoke.  Stairway Pressurization: a type of containment smoke control system in which stair shafts are mechanically pressurized, with respect to the fire area, with outdoor air to keep smoke from contaminating them during a fire incident  Floating Zone/Floor-by-Floor Pressurization: a mechanical method of smoke control in which 100% outdoor air is pumped onto the floors above and below the fire floor, forming a pressure barrier around the fire and mechanically relieving or exhausting the air from the fire floor. This method is most successful when all non-fire floors are pressurized  Elevator Hoistway Pressurization: a mechanical method of smoke control in which 100% outdoor air is pumped into the elevator hoistway at an increased pressure, forming a pressure barrier that prevents smoke and gases from entering the elevator shaft

 Refuge Area Pressurization: a mechanical method of smoke control in which 100% outdoor air is pumped into the refuge area at an increased pressure, forming a pressure barrier that prevents smoke and gases from entering the refuge area. 5. Which two of the four pressure differential methods are most commonly used for a high-rise building and which one is more difficult to design? Stairway pressurization and floor-by-floor/floating zone pressurization. Floating zone pressurization is more difficult to design 6. Which of the smoke control methods is best suited for a large volume space such as an atrium, and why? Smoke removal: provides vertical cross flow ventilation from floor to roof or horizontal cross flow from ventilation from non-fire to fire areas 7. Why is the opposed air method of smoke control rarely used? It is because it is rarely used alone. It is often used in conjunction with the pressurization or exhaust methods. It also uses the building features such as doors and windows to help control the smoke 8. What are the different life safety and fire protection systems that interface with smoke control systems? Smoke control and management systems interconnect with fire protection systems, HVAC systems, elevator systems, and backup power systems to initiate the appropriate control sequences and response when a fire emergency arises. Coordination of smoke control zones, fire sprinkler zones, and fire alarm and detection zones is important to establish the proper relationship between these systems. When functioning properly, dampers on air supply and relief systems open or close, the HVAC systems turn on or shut down, elevator cars locate at predetermined floor levels, an backup power systems stand ready to provide power when there is a loss of primary power to the smoke control system 9. What initiation device is not recommended for use with smoke control and management systems, and why? Manual fire alarm pull stations should not be used to activate automatic smoke control systems, other than stairwell pressurization systems. The reason for this is because of the likelihood that a person may signal an alarm from a station outside of the smoke zone reason

10. Discuss the pros and cons of requiring smoke control and management systems. Which use and occupancy conditions would benefit from the installation of these systems, and which would not? The pros are that the systems are designed to provide a tenable environment in a building during a fire emergency, and, to a degree, keep hot gases and smoke confined. The cons are that these systems can be a challenge to design and require that the property owner or responsible party keep up with the required periodic inspection and testing. Without annual testing and receipt of documented reports, smoke control systems can rapidly fall into a state of disrepair or failed performance; this is particularly true in multi-tenant office buildings during the initial build-out of first-generation tenants. Problems may occur due to reprogramming of the fire alarm system for new tenant alarm devices, electrically disconnecting systems due to nuisance operation, damper motors failing to operate, intentionally disconnecting damper linkages, and fan motors tripped on thermal overload. Occupancies that would benefit include any place where there is an evacuation challenge, any location where it could take time to reach the exit discharge such as a high-rise or subway station, large open space occupancies, and any location where people are not free to move about 11. What are the different elements of the smoke control acceptance test plan, and why is it so important to perform annual smoke control system inspection and testing? The smoke control acceptance test plan provides the description of the smoke control systems, the design criteria, how these criteria will be demonstrated and proved, what will constitute successful performance, the step-by-step procedures, and the test instrumentation and equipment that will be used in the process. Testing at the functional level and integrated performance level involves recording smoke control system response time, air pressure differential across smoke barriers (e.g., stairway/refuge enclosures, elevator hoistway/refuge enclosures, horizontal floor separations, atria and adjacent areas, miscellaneous smoke compartments), and door opening forces in the direction of egress.

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The testing usually occurs after all other life safety and fire protection systems have been successfully tested and approved because the system relies on the fire protection systms to properly operate. Testing smoke control is not much different from testing other fire protection systems. OTHER ANSWER Testing usually follows the testing of all other life safety and fire protection systems. Process usually starts with operational testing at the component level and continues with functional testing of individual systems. All tests should be witnessed and documented. Systems should undergo functional and performance testing on an annual basis. Annual tests should address the functional performance of individual components and systems as well as the integrated performance verification. Individual system and integrated performance testing should be done by trained personnel who have the same qualifications as the person who did the initial acceptance testing. 12. Who are the different individuals or organizations that should be present at the acceptance test of a smoke control system, and why? Generally, the design professional who designed the smoke control system develops a detailed test plan that provides the description of the smoke control systems, the design criteria, how these criteria will be demonstrated and proved, what will constitute successful performance, the step-by-step procedures, and the test instrumentation and the equipment that will be used in the process REFER