The document discusses smoke extraction in buildings, including key factors in smoke extraction design such as design fire size, smoke layer depth, smoke reservoirs, minimum number of extract points, inlet air, ductwork, and performance criteria for fire resisting ductwork. Effective smoke extraction requires considering smoke pathways, production, and movement, and extraction methods vary depending on building type, such as for multi-story offices, warehouses, underground parking, atriums, and shopping malls. Following approved agency guidance can significantly reduce fire and smoke threats.

1. SMOKE EXTRACTION IN BUILDINGS Presented by VysakhManohar GATE-Chennai Tuesday, June 07, 2011 1 Smoke Extraction In Buildings

2. INTRODUCTION Effective smoke extraction in buildings has been one of the inevitable considerations in the building design as the number of buildings and the concern of people about the regular fire accidents in buildings are increasing much. This presentation includes a brief description about the different design consideration principles and methods to be taken care for the effective heat extraction in different types of buildings . Tuesday, June 07, 2011 2 Smoke Extraction In Buildings

3. What is smoke? By product of combustion or pyrolysis . Mixture of liquid , solid particulate matter and gaseous products. It is a cocktail of carbon monoxide, carbon dioxide ,HCL and HCN Tuesday, June 07, 2011 3 Smoke Extraction In Buildings

4. FIRE TIME LINE 00.00- Household is asleep 00.30- Fire ignites and grows in downstairs 1.04- Fire spreads and smoke begins to fill In the room. 1.35- Smoke layer descends rapidly and temperature exceeds 88 deg 1.50 – Smoke detector sounds an alarm. 2.30- Temperature becomes 205 deg 2.48- smoke pours into other rooms Tuesday, June 07, 2011 4 Smoke Extraction In Buildings

5. 3.03-Temperature in the room becomes more than 260 deg 3.20-upstairs,corridors,all the rooms are filled with smoke 3.41- flashover occurs , temperature becomes 760 deg 3.50 –Two minutes after the alarm sound, only the second exit will be the way out 4.33- Flames will be apparent from the outside , the first evidence of fire visible from outside. Tuesday, June 07, 2011 5 Smoke Extraction In Buildings

6. Will follow similar scenario in other location The variations will be based on 1-fire size 2-size of building 3-flammable materials in the building 4-alarm systems 5-safety measures available Tuesday, June 07, 2011 6 Smoke Extraction In Buildings

7. GETTING THE DESIGN RIGHT FROM THE BEGINNING Factors affected Design fire size Stack and wind effects Temperature effect of fire HVAC and ventilation systems Climate Expansion of ducts

8. COMMON SAFETY METHODS Use sprinklers Smoke curtains HVAC system incorporating F & S dampers. Extraction fans Alarm systems Pressurisation Tuesday, June 07, 2011 8 Smoke Extraction In Buildings

9. HAZARDS OF DANGEROUS SMOKE Impair visibility Coughing,nausea,vomiting Generation of high temperature Irritation and respiratory problems Bronchospasms and hypoxia Inflict death if it contains dangerous gases Even low concentration of CO can cause diminished coordination and increased disorientation Amount of oxygen is reduced- suffocation Exacerbate corrosive nature of HCL Tuesday, June 07, 2011 9 Smoke Extraction In Buildings

10. Smoke Pathways Air and service ducts connecting floors HVAC/ventilation systems Extract duct systems Gaps between wall and floor constructions Stairwells Lift shafts Tuesday, June 07, 2011 10 Smoke Extraction In Buildings

11. Need of smoke extraction for life safety and reducing property loss for fire fighter access To clear smoke after a fire –smoke purging Tuesday, June 07, 2011 11 Smoke Extraction In Buildings

12. Smoke extraction design objectives Effective protection of building occupants by maintaining tenable conditions on egress systems. Reliable and functional fire fighting controls used by firefighters to increase visibility and reduce heat exposure. Tuesday, June 07, 2011 12 Smoke Extraction In Buildings

13. Make up air routes External doors Louvers in wall or roof Central air plant configured to supply air From adjacent unaffected areas ->avoid mixing of smoke and make up air ->extraction points-avoid creation of “hole” Tuesday, June 07, 2011 13 Smoke Extraction In Buildings

14. Smoke Production and movement Amount of smoke produced is dependent on size of fire Path through which it goes Plume height Tuesday, June 07, 2011 14 Smoke Extraction In Buildings

15. Fundamental design factors Design fire size Smoke layer depth Identify smoke reservoirs Calculate smoke volume and temperature Minimum number of extract points Vent or fan size and fan temperature rating Inlet air Duct work Tuesday, June 07, 2011 15 Smoke Extraction In Buildings

16. Design fire size Fire starts small and becomes large Vent area=2.5 % of floor area-otherwise mechanical 6 ac/hour is used often Design fire size is greatly dependent on building contents. Based on the largest fire source Cannot surely withstand post flash over conditions Tuesday, June 07, 2011 16 Smoke Extraction In Buildings

17. Heat output of fire National bureau of standards in USA Based on time- safe escape time brigade response time Tuesday, June 07, 2011 17 Smoke Extraction In Buildings

18. Acceptable smoke layer depth Smoke layer base should be above the people 2.5 m-single storey 3 m - upper storey of 2 storey Tuesday, June 07, 2011 18 Smoke Extraction In Buildings

19. Smoke reservoirs If smoke is held in a too large reservoir-lose buoyancy 2000 m^2 - natural extraction 2600 m^2 -powered extraction Smoke curtains can be used to reduce horizontal spread Tuesday, June 07, 2011 19 Smoke Extraction In Buildings

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21. Smoke- volume, mass flow rate and temperature T=Q/m cp 1/3 is gained by building structure Tuesday, June 07, 2011 21 Smoke Extraction In Buildings

22. Minimum no of extract points Mcr is not exceeded No smoke need to travel more than 30 m to extraction point Tuesday, June 07, 2011 22 Smoke Extraction In Buildings

23. Inlet air To make up the smoky gases At least 1.5m beneath smoke layer If natural inlet is given Inlets should be away from the outlets Inlet velocity should be less than 3 m/s Tuesday, June 07, 2011 23 Smoke Extraction In Buildings

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25. Ductwork Must be able to withstand anticipated temp- From the formula HVCA specification DW144 For sprinkled buildings To limit fire spread -fire protection of steel ducts -construct from proprietary material - use fire and smoke dampers Tuesday, June 07, 2011 25 Smoke Extraction In Buildings

26. Fire resisting requirement of ductwork To prevent fire inside one duct to breaking out to other compartment. To prevent fire from outside enter into duct and then enter another fire compartment To prevent fire from outside enter into duct and the break out into other compartment Tuesday, June 07, 2011 26 Smoke Extraction In Buildings

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29. Performance criteria for fire resisting duct work Stability Integrity Insulation Tuesday, June 07, 2011 29 Smoke Extraction In Buildings

30. Other things to be noted Duct must be able to retain at least 75% of its size after the smoke removal. Sound or thermal insulation should not be raised to ignition temperature. Fire stopping seals should be used Buckling or collapse. Tuesday, June 07, 2011 30 Smoke Extraction In Buildings

31. Construction of fire resisting smoke extract ducts a) galvanized steel duct with additional protection b) fire resisting boards(eg . calcium silicate) c)proprietary fire resistant ductwork eg: PROMATECT-H Tuesday, June 07, 2011 31 Smoke Extraction In Buildings

32. Protection of duct with fire resisting board Tuesday, June 07, 2011 32 Smoke Extraction In Buildings

33. Ductwork construction from fire resisting board Tuesday, June 07, 2011 33 Smoke Extraction In Buildings

34. Spreading of smoke Tuesday, June 07, 2011 34 Smoke Extraction In Buildings

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38. Design guide for different building types Multi-storey office and similar buildings Warehouse Underground car parks/basement Atrium buildings Shopping malls Tuesday, June 07, 2011 38 Smoke Extraction In Buildings

39. Multi storey office and similar buildings Phased evacuation Evacuation time will be varying Smoke should not spread 1, smoke extraction 2, pressurisation The recirculation of air in normal hvac system is prevented by dampers Tuesday, June 07, 2011 39 Smoke Extraction In Buildings

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41. Important design considerations The system is not for providing a smoke free layer Both supply and extract ducts should be having fire resistance equal to that of the floors /walls Exhaust fans should be able to run at the highest expected temperature Tuesday, June 07, 2011 41 Smoke Extraction In Buildings

42. The power supply to the system must be duplicated The power and instrumentation cabling should be of fire resistant type Smoke and fire dampers should be having suitable specification-UL555s class-I,II,III,IV in high storey buildings-wind pressure Tuesday, June 07, 2011 42 Smoke Extraction In Buildings

43. Ware houses Tuesday, June 07, 2011 43 Smoke Extraction In Buildings

44. Underground car parks/basement Tuesday, June 07, 2011 44 Smoke Extraction In Buildings

45. ATRIUM CONSTRUCTIONS Fully enclosed atrium Partially opened atrium Fully opened atrium Tuesday, June 07, 2011 45 Smoke Extraction In Buildings

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47. Fully enclosed atrium Tuesday, June 07, 2011 47 Smoke Extraction In Buildings

48. Enclosures are 2 types 1- fire resisting enclosure-fire resisting glazing 2- enclosure of limited combustibility but not fire resisting Tuesday, June 07, 2011 48 Smoke Extraction In Buildings

49. Partially enclosed atrium Tuesday, June 07, 2011 49 Smoke Extraction In Buildings

50. Fully open atrium Tuesday, June 07, 2011 50 Smoke Extraction In Buildings

51. Shopping malls Tuesday, June 07, 2011 51 Smoke Extraction In Buildings

52. Extract from single shops Smoke is prevented to enter to mall area Very large fans are not required But complex and costly Shops must be sprinkled Combined duct work is used to reduce cost Tuesday, June 07, 2011 52 Smoke Extraction In Buildings

53. Extract from mall Tuesday, June 07, 2011 53 Smoke Extraction In Buildings

54. Channeling screens Tuesday, June 07, 2011 54 Smoke Extraction In Buildings

55. Limitations With high atriums there is a cut off point of mass flow rate of 150 to 250 kg/s-economically impractical. Temperature stratification Cooling effect Tuesday, June 07, 2011 55 Smoke Extraction In Buildings

56. Fire,smoke and building code agencies Industrial risk insurers (IRI) Southern building code congress inc(SBCCI) National fire protection association(NFPA) Underwriters Laboratories(UL) British standards(BS) National Building Standards(NBS) Tuesday, June 07, 2011 56 Smoke Extraction In Buildings

57. CONCLUSION By following discriminative approaches and methods needed for different types of buildings and constructions provided by the different approved agencies ,the threat from fire and smoke can be reduced to a considerable level. Tuesday, June 07, 2011 Smoke Extraction In Buildings 57

58. References Promat International Ltd National Fire protection Association,Guide for smoke and heat venting,NFPA-204 M BS 5839: Fire Protection and alarm systems in buildings,Part1 2002 Underwriters Laboratories,Leakage rated dampers for use in smoke in control systems,UL555 S Tuesday, June 07, 2011 58 Smoke Extraction In Buildings

59. THANKING YOU ALL…….. Tuesday, June 07, 2011 59 Smoke Extraction In Buildings