Formulas Flashcards
What is 1 ft2 EDR equal to in Btuh?
240Btuh
How many lbs does 1 U.S Gallon weigh?
8.33 lb
How many Btu’s are in 1 cooling ton?
12 000 BTU
What is Charle’s Law?
V1 / T1 = V2 / T2
What is the formula for determining expansion of a pipe?
Length x Delta T x Coefficient of expansion
What is the formula for Total Force?
Pressure x Area
What is the formula for determining flow to a heating zone?
GPM = BTU / (lb./gal. x delta T)
What is the formula used to determine heat transfer rate in btu/min?
Total BTU / (Delta T x Mass x Minutes x Specific Heat Capacity)
How do you calculate grade of a piping run?
Drop or Rise / Run
How do you calculate grains in water?
Grains = (# of persons x gal. per day) x (hardness in grains + iron concentration) x days of regeneration + 20%
How do you calculate the load for a RWL?
Litres = Area x 15min rainfall data or Area + Half the area of the largest adjacent wall x 15min rainfall data
How do you calculate pressure?
Height x Density
What is the unit of conversion for pressure head (psi/ft)?
0.433 psi/ft
How do you calculate Delta T for a hydronic system?
Btuh / (500 x gpm)
How do you calculate the travel of a 45 degreee offset?
C-C offset x 1.414
How do you calculate gpm for a hydronic system?
Btuh / (500 x delta T (water))
How do you calculate Btuh for a hydronic system?
gpm x 500 x delta T
How do you calculate area of a circle?
π x r2
How do you calculate the area of a cylinder with an open top?
π x r2 + π x dia. x H
How do you calculate the area of a cylindrical tank?
2(π x r2) + π x dia. x H
How do you calculate the area of a rectangular box with an open top?
(L x W) + 2(W x H) + 2(L x H)
How do you calculate the area of a rectangular box, totally enclosed?
2(L x W) + 2(W x H) + 2(L x H)
How do you calculate the area of a rectangle?
L x W
How do you calculate the area of a circle?
π x dia.2
