1. Per ASHRAE 1993 Fundamantals @68 Degf

2. Adapted from ASHRAE 1993 Fundamantals

Method for calculating the volume of fluid required to combine with water when the mixture is defined by weight:

V2 = V1/(1+(SG(100%-P))/P)

Where:

V1 = System Volume

V2 = Required Volume of Pure Additive

P = Percent of system that is Additive (by weight)

SG = Specific Gravity of Additive

Example:

How many gallons of Ethylene Glycol are required for a 1,000gallon system to be 30% ethylene glycol by weight? (Note: The Specific Gravity of Ethylene Glycol is 1.116)

Solution: Gallons(E.G.) = 1,000/(1+(1.1155(100%-30%)/30 %)) = 277.6

Note: Had this been Propylene Glycol, the value for Specific Gravity would have been 1.038