DRAFT & ITS TYPESDraft: Diference between atmospheric pressure and furnace pressure is caed draft!"to somethin# pu to e$er%sefcaed draftT%pes of Draft: a!&atura draft b!Forcecd draft c!Induced draft d!'aence draft e!Posti$e draft f!&e#ati$e draft #!(echanica draft&atura: )a$in# no fan Run due to the pressure of the air )a$in# two thin#s"*+%#en "'urnt #ases'urnt #ases are ower wei#hts ,the% #o upward and than repaces b% o+%#en!Thats wh% combustion occursForced: In this F!D Fan is used(!(ahmood -han Pa#e .DRAFT & ITS TYPES )e bows air in the furnace Its pressure is / inch to 01 inch water coumn #reater than the atmospheric pressure In furnace burnt #ases #oes outside from furnacedue to pressure in furnace!Induced: In this I!D Fan is used That catch 2ue #ases from furnace to chimne% toatmosphere )ere paced ne#ati$e pressure that for burnin# air b% itsef re enters air inside!'aance: In this both I!d fan and f!d fab both are used F!d fan #i$es air to furnace I!d fan catch 2ue #ases from chimne% to atmosphere It maintain / inch water coumn in furnace )a$e ne#ati$e pressurePositi$e: That uses F!d fan Its pressure is #reater than the atmospheric pressure(!(ahmood -han Pa#e 3DRAFT & ITS TYPES&e#ati$e:That uses I!D Fan Its pressure is ess than the atmospheric pressure (!(ahmood -han Pa#e 0