DC Boiler Exam Prep (Formulas and constants used for the DC 3rd class boiler exam) Latest Update

DC Boiler Exam Prep (Formulas and constants used for the DC 3rd class boiler exam) Latest Update Area of a rectangle - ANSWER>>Length x Width Area of a Circle - ANSWER>>.7854 x Diameter² Volume of a Box - ANSWER>>Length x Width x Height Volume of a Cylinder - ANSWER>>.7854 x Diameter² x Length Circumference of a Circle - ANSWER>>π x Diameter Unit of Force - ANSWER>>Pound (lb) Formula for Force - ANSWER>>Pressure ÷ Area Unit of Work - ANSWER>>in-lb or ft-lb Formula for Work - ANSWER>>Force x Distance Unit of Power - ANSWER>>ft-lb/min Formula for Power - ANSWER>>= Work ÷ Time or (Force x Distance) ÷ Time Formula for Mechanical Horsepower - ANSWER>>= Power ÷ 33,000 ft-lb/min Safe Working Pressure of a Riveted Boiler (SWP) - ANSWER>>(Area of Staybolt x Stress Constant of Staybolt) ÷ Area Covered by Staybolt or = (a x C) ÷ A Area Covered by Staybolt - ANSWER>>= Pitch x Pitch Longitudinal Stress - ANSWER>>(P x D x L) / 2t P = Pressure D = Diameter L = Length t = thickness of steel Boiler Heating Surface (tubes) = - ANSWER>>= C x L x # C = Circumference of tubes L = Length of tubes # = Number of tubes HS = π x Diameter x Length x Number of Tubes Watts per Boiler Horsepower - ANSWER>>746 Watts Horsepower formula - ANSWER>>= ft-lb/min ÷ 33000 ft-lb/min ft-lb formula for a pump - ANSWER>>= gpm x 8.33 x head (ft) Factor of Evaporation (FE) = - ANSWER>>= [Hs - (tfw-32)] ÷ 970.3 Hs = Enthalpy of steam tfw = temperature of feed water Latent Heat of Vaporization for Water - ANSWER>>970.3 Btu/lb Latent Heat of Fusion for Water - ANSWER>>144 Btu/lb 1 Boiler Horsepower = x lbs of steam generator per hour - ANSWER>>34.5 lbs/hr 1 Boiler Horsepower = x Btu/hr - ANSWER>>33,475 Btu/hr 1 BHP = x ft² of heating surface (general) - ANSWER>>10 ft² heating surface Volume of water increases by x percent when it flashes to steam - ANSWER>>x 1600 Thermal Efficiency (TE) = - ANSWER>>= Lbs Steam per hour [Hs -(fwt° -32)] ÷ Units of Fuel per hour x Btu content per unit of fuel Hs = Btu content of steam fwt = feed water temperature Developed Boiler Horsepower (DBHP) = - ANSWER>>= (Pounds of Steam per hour (Ws) x FE) ÷ 34.5 Ws = Lbs of steam per hour FE = Factor of Evaporation Maximum Allowable Working Pressure (MAWP) - ANSWER>>= (TS x t x E) / FS x r TS = Tensile Strength of steel t = thickness of steel E = Efficiency of joint