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 byVysakhManoharGATE-ChennaiTuesday, June 07, 20111Smoke Extraction In Buildings

2. INTRODUCTIONEffective 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, 20112Smoke 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 HCNTuesday, June 07, 20113Smoke Extraction In Buildings

4. FIRE TIME LINE00.00- Household is asleep00.30- Fire ignites and grows in downstairs1.04- Fire spreads and smoke begins to fillIn the room.1.35- Smoke layer descends rapidly and temperature exceeds 88 deg1.50 – Smoke detector sounds an alarm.2.30- Temperature becomes 205 deg2.48- smoke pours into other roomsTuesday, June 07, 20114Smoke Extraction In Buildings

5. 3.03-Temperature in the room becomes more than 260 deg3.20-upstairs,corridors,all the rooms are filled with smoke3.41- flashover occurs , temperature becomes 760 deg 3.50 –Two minutes after the alarm sound, only the second exit will be the way out4.33- Flames will be apparent from the outside , the first evidence of fire visible from outside.Tuesday, June 07, 20115Smoke Extraction In Buildings

6. Will follow similar scenario in other locationThe variations will be based on 1-fire size 2-size of building 3-flammable materials in the building 4-alarm systems 5-safety measures availableTuesday, June 07, 20116Smoke Extraction In Buildings

7. GETTING THE DESIGN RIGHT FROM THE BEGINNINGFactors affected Design fire size Stack and wind effectsTemperature effect of fire HVAC and ventilation systemsClimate Expansion of ducts

8. COMMON SAFETY METHODSUse sprinklersSmoke curtainsHVAC system incorporating F & S dampers.Extraction fansAlarm systemsPressurisationTuesday, June 07, 20118Smoke Extraction In Buildings

9. HAZARDS OF DANGEROUS SMOKEImpair visibilityCoughing,nausea,vomitingGeneration of high temperatureIrritation and respiratory problemsBronchospasms and hypoxiaInflict death if it contains dangerous gasesEven low concentration of CO can cause diminished coordination and increased disorientationAmount of oxygen is reduced- suffocationExacerbate corrosive nature of HCLTuesday, June 07, 20119Smoke Extraction In Buildings

10. Smoke PathwaysAir and service ducts connecting floorsHVAC/ventilation systemsExtract duct systemsGaps between wall and floor constructionsStairwellsLift shaftsTuesday, June 07, 201110Smoke Extraction In Buildings

11. Need of smoke extraction for life safety and reducing property loss for fire fighter accessTo clear smoke after a fire –smoke purgingTuesday, June 07, 201111Smoke Extraction In Buildings

12. Smoke extraction design objectivesEffective 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, 201112Smoke Extraction In Buildings

13. Make up air routesExternal doorsLouvers in wall or roofCentral air plant configured to supply airFrom adjacent unaffected areas->avoid mixing of smoke and make up air->extraction points-avoid creation of “hole”Tuesday, June 07, 201113Smoke Extraction In Buildings

14. Smoke Production and movementAmount of smoke produced is dependent on size of firePath through which it goesPlume heightTuesday, June 07, 201114Smoke Extraction In Buildings

15. Fundamental design factorsDesign fire sizeSmoke layer depthIdentify smoke reservoirsCalculate smoke volume and temperatureMinimum number of extract pointsVent or fan size and fan temperature ratingInlet airDuct workTuesday, June 07, 201115Smoke Extraction In Buildings

16. Design fire sizeFire starts small and becomes largeVent area=2.5 % of floor area-otherwise mechanical6 ac/hour is used oftenDesign fire size is greatly dependent on building contents.Based on the largest fire sourceCannot surely withstand post flash over conditionsTuesday, June 07, 201116Smoke Extraction In Buildings

17. Heat output of fireNational bureau of standards in USABased on time- safe escape time brigade response timeTuesday, June 07, 201117Smoke Extraction In Buildings

18. Acceptable smoke layer depthSmoke layer base should be above the people2.5 m-single storey3 m - upper storey of 2 storeyTuesday, June 07, 201118Smoke Extraction In Buildings

19. Smoke reservoirsIf smoke is held in a too large reservoir-lose buoyancy2000 m^2 - natural extraction2600 m^2 -powered extractionSmoke curtains can be used to reduce horizontal spreadTuesday, June 07, 201119Smoke Extraction In Buildings

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21. Smoke- volume, mass flow rate and temperatureT=Q/m cp1/3 is gained by building structureTuesday, June 07, 201121Smoke Extraction In Buildings

22. Minimum no of extract pointsMcr is not exceededNo smoke need to travel more than 30 m to extraction pointTuesday, June 07, 201122Smoke Extraction In Buildings

23. Inlet airTo make up the smoky gasesAt least 1.5m beneath smoke layerIf natural inlet is givenInlets should be away from the outletsInlet velocity should be less than 3 m/sTuesday, June 07, 201123Smoke Extraction In Buildings

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25. DuctworkMust be able to withstand anticipated temp- From the formulaHVCA specification DW144For sprinkled buildingsTo limit fire spread -fire protection of steel ducts -construct from proprietary material - use fire and smoke dampersTuesday, June 07, 201125Smoke Extraction In Buildings

26. Fire resisting requirement of ductworkTo prevent fire inside one duct to breaking out to other compartment.To prevent fire from outside enter into duct and then enter another fire compartmentTo prevent fire from outside enter into duct and the break out into other compartmentTuesday, June 07, 201126Smoke Extraction In Buildings

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29. Performance criteria for fire resisting duct workStabilityIntegrityInsulationTuesday, June 07, 201129Smoke Extraction In Buildings

30. Other things to be notedDuct 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 usedBuckling or collapse.Tuesday, June 07, 201130Smoke 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 ductworkeg: PROMATECT-HTuesday, June 07, 201131Smoke Extraction In Buildings

32. Protection of duct with fire resisting boardTuesday, June 07, 201132Smoke Extraction In Buildings

33. Ductwork construction from fire resisting boardTuesday, June 07, 201133Smoke Extraction In Buildings

34. Spreading of smokeTuesday, June 07, 201134Smoke Extraction In Buildings

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38. Design guide for different building typesMulti-storey office and similar buildingsWarehouseUnderground car parks/basementAtrium buildingsShopping mallsTuesday, June 07, 201138Smoke Extraction In Buildings

39. Multi storey office and similar buildingsPhased evacuationEvacuation time will be varyingSmoke should not spread 1, smoke extraction 2, pressurisationThe recirculation of air in normal hvac system is prevented by dampersTuesday, June 07, 201139Smoke Extraction In Buildings

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41. Important design considerationsThe system is not for providing a smoke free layerBoth supply and extract ducts should be having fire resistance equal to that of the floors /wallsExhaust fans should be able to run at the highest expected temperatureTuesday, June 07, 201141Smoke Extraction In Buildings

42. The power supply to the system must be duplicatedThe power and instrumentation cabling should be of fire resistant typeSmoke and fire dampers should be having suitable specification-UL555s class-I,II,III,IV in high storey buildings-wind pressure Tuesday, June 07, 201142Smoke Extraction In Buildings

43. Ware housesTuesday, June 07, 201143Smoke Extraction In Buildings

44. Underground car parks/basementTuesday, June 07, 201144Smoke Extraction In Buildings

45. ATRIUM CONSTRUCTIONSFully enclosed atriumPartially opened atriumFully opened atriumTuesday, June 07, 201145Smoke Extraction In Buildings

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47. Fully enclosed atriumTuesday, June 07, 201147Smoke Extraction In Buildings

48. Enclosures are 2 types 1- fire resisting enclosure-fire resisting glazing 2- enclosure of limited combustibility but not fire resistingTuesday, June 07, 201148Smoke Extraction In Buildings

49. Partially enclosed atriumTuesday, June 07, 201149Smoke Extraction In Buildings

50. Fully open atriumTuesday, June 07, 201150Smoke Extraction In Buildings

51. Shopping mallsTuesday, June 07, 201151Smoke Extraction In Buildings

52. Extract from single shopsSmoke is prevented to enter to mall areaVery large fans are not requiredBut complex and costlyShops must be sprinkledCombined duct work is used to reduce costTuesday, June 07, 201152Smoke Extraction In Buildings

53. Extract from mallTuesday, June 07, 201153Smoke Extraction In Buildings

54. Channeling screensTuesday, June 07, 201154Smoke Extraction In Buildings

55. LimitationsWith high atriums there is a cut off point of mass flow rate of 150 to 250 kg/s-economically impractical. Temperature stratificationCooling effectTuesday, June 07, 201155Smoke Extraction In Buildings

56. Fire,smoke and building code agenciesIndustrial 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, 201156Smoke Extraction In Buildings

57. CONCLUSIONBy 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, 2011Smoke Extraction In Buildings57

58. ReferencesPromat International LtdNational Fire protection Association,Guide for smoke and heat venting,NFPA-204 MBS 5839: Fire Protection and alarm systems in buildings,Part1 2002Underwriters Laboratories,Leakage rated dampers for use in smoke in control systems,UL555 STuesday, June 07, 201158Smoke Extraction In Buildings

59. THANKING YOU ALL……..Tuesday, June 07, 201159Smoke Extraction In Buildings