SMOKE CONTROL: ISSUES / APPROACHES. Smoke, Not Flame

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1 SMOKE CONTROL: ISSUES / APPROACHES Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 1 Smoke, Not Flame The most significant cause of death in building fires is smoke, which accounted for 73% of fire-related deaths in 1990, according to a 1994 report by the NFPA. However, fires also can cause structural collapse of buildings, and burns cause the remainder of deaths in fire. Larry Gelin, Johns Manville no more recent specific data are available Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 2 1

2 Smoke, A BSU Example Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 3 Smoke, A BSU Example repeat after me code = minimum code = minimum code = minimum code = minimum code = minimum Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 4 2

3 Smoke, A BSU Example the codes didn t require it the budget wouldn t allow it Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 5 Smoke Is defined (by ASHRAE) as: products of combustion and associated solids, liquids, and gasses. Essentially smoke is anything and everything that becomes airborne as a result of a fire. Smoke is related to fire, but does not behave the same as fire or affect people the same as fire. Fire solutions are not necessarily smoke solutions. Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 6 3

4 Smoke Hazards Asphyxiation (lack of oxygen) Toxicity (poisoning) Obscuration (reduced visibility) Psychological disorientation (loss of judgment) Combustibility Building materials damage affects people affects building the bottom line: smoke is dangerous Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 7 Reflecting on Smoke Hazards kills occupants Asphyxiation (a problem for millennia) Toxicity (a more recent problem caused by combustion of plastics) impedes egress Obscuration (a problem for millennia) Psychological disorientation (a more recent problem caused by combustion of plastics) modern construction materials and furnishings have upped the ante Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 8 4

5 Smoke Spreads via Temperature expansion Hot air/gas expands; this action will cause smoke to move in all directions (up, down, sideways away from the source) Stack effect Hot air rises; this action will cause upward smoke movement Air-handling unit Air circulation through action of an AHU; this action supports smoke movement along the HVAC system ductwork paths Wind Causes pressure differences; this action causes smoke movement in unpredictable directions determined by wind direction and window breakage Molecular diffusion Partial-pressure-of-gasses effect; this causes smoke movement away from the source in all directions (a weak, but persistent, action) the bottom line: smoke can move readily Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 9 Temperature Expansion PLAN SECTION modes of smoke spread Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 10 5

6 Stack Effect PLAN SECTION modes of smoke spread Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 11 Air-Handling Unit PLAN SECTION modes of smoke spread Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 12 6

7 Wind PLAN SECTION modes of smoke spread Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 13 Molecular Diffusion PLAN SECTION modes of smoke spread Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 14 7

8 Smoke Control is Very Important Smoke in a building presents numerous hazards, some lethal Smoke in a building, if not constrained, can easily move up, down, and sideways An unrestrained flow of a hazardous substance is not a good design outcome Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 15 Smoke Control Two General Approaches Containment To keep smoke from moving (using air-tight barriers and intentional pressure differences) Dilution To reduce smoke concentration (through the exhaust of smoke and/or infusion of fresh air) Dilution and containment can be mixed and matched to protect those in the both the smoke-producing part of a building and those in other areas Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 16 8

9 Smoke Control: Code Requirements Building code requirements regarding smoke control are generally scattered, occasionally outdated, and now and then conflicting. In most larger buildings, the smoke control system will be custom designed for the building and may require a variance from the building official in charge (the AHJ). All such systems should be fully commissioned. Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 17 Smoke Control: Code Requirements ICC: International Fire Code Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 18 9

10 Smoke Control: Code Requirements ICC: International Fire Code Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 19 Smoke Control: Code Requirements ICC: International Fire Code Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 20 10

11 building code requirements are of two broad types: prescriptive (do this) and performance (accomplish something) smoke control is performance-based Smoke Control: Code Requirements ICC: International Fire Code the gist of these excerpts is to suggest that smoke control systems are treated differently from most other building systems; that they are customized, and must pass operational verification testing Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 21 Smoke Control Some Specific Methods Smoke-free stairways (or corridors) Intrinsically protected (open air arrangements) or protected via pressure controls (engineered air supplies) Smoke-free elevators (very, very difficult) Via venting or pressure controls Areas of refuge Via smoke barriers and pressurization Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 22 11

12 Smoke Control Some Specific Methods Smoke-free atria (as part of a means of egress) High-volume exhaust (fans) Large inlet openings (automatic doors often used, or louvers with dampers) Distributed smoke detection (often quite sophisticated) Typically, system effectiveness must be demonstrated to a code official (the AHJ: authority having jurisdiction) before system will be accepted Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 23 Atrium Smoke Control A Current Topic Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 24 12

13 11/11/2018 Atrium Smoke Control: A Current Topic ^^ smoke spread scenarios smoke exhaust problems >> ASHRAE Journal, June 2012 Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 25 Testing an Atrium Smoke Control System the test starts, so far so good then, not looking so good increasingly deep unexhausted smoke layer occupants Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 26 13

14 Example Area of Refuge Scenario large floor plate supply air return air AHU other core elements: bathroom, fire stair, electrical closet, etc. AHU looking at a schematic floor plan, with two air-handling units serving the floor Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 27 A Fire Breaks Out on the Floor without an intentional smoke control response smoke fills the floor and leaks onto adjacent floors supply air return air Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 28 14

15 Smoke Control System Response supply air without return/exhaust closed open open return/exhaust without supply air closed the HVAC system, in conjunction with smoke barriers (red lines), establishes an area of refuge on part of the floor by pressurizing (pos) and depressurizing (neg) portions of the floor in order to control and direct smoke flow Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 29 Area of Refuge at Egress (protected from fire and from smoke) within stairwell at elevators & stairwell note the spatial impacts of these solutions Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 30 15

16 Pressurization r e t r o f i t some serious airflow (into hotel room from a pressurized corridor); in a fire situation this is good as long as corridor is not source of smoke Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 31 Smoke Detector in Return Duct smoke detectors are used to control smoke system operation Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 32 16

17 Smoke-Free Stairway an interesting concept; with spatial layout implications vestibule: pressurized or depressurized to space >> << to fire stair Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 33 Smoke-Free Stairway a new construction retrofit lack of stairwell smoke control was caught during construction by the AHJ and a fix was required Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 34 17

18 The Latest NFPA Statistics on Sprinkler Performance NFPA Journal, March/April 2008 Based on fires reported to U.S. fire departments from 2002 through 2004, excluding cases of failure or ineffectiveness because of a lack of sprinklers in the fire area, sprinklers operate in 93 percent of all reported structure fires large enough to activate sprinklers. When they operate, they are effective 97 percent of the time, resulting in a combined performance reliability of 90 percent. The combined performance reliability for the more widely used wet-pipe sprinklers is 91 percent, while the combined performance reliability for dry-pipe sprinklers is 83 percent. By comparison, the combined performance reliability for dry-chemical systems is only 49 percent, but it s 90 percent for carbon dioxide systems. When sprinklers fail to operate, the reason most often given is that the system was shut off before the fire began... Other leading reasons are manual intervention that defeated the system, lack of maintenance, and inappropriate system for the type of fire. Only 2 percent of sprinkler failures are attributed to component damage. Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 35 and changing the topic the award for best attempt to hide a supply air register goes to the Austin, TX, convention center Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 36 18