ANTIFREEZE HYDRAULIC CALC
ANTIFREEZE HYDRAULIC CALC
(OP)
Does nfpa 13 require a special calc using Darcy-Weisbach formula for antifreeze systems or is it just recommended? In a small attic system less than 40 gallons would the Hazen-Williams calc [we use hydracalc] be close enough?





RE: ANTIFREEZE HYDRAULIC CALC
Hydracalc can do DW calcs provided you're not using an outdated version.
22.4.4.5 Design Densities.
22.4.4.5.1* For antifreeze solutions greater than 40 gal (151 L) in size, the friction loss shall also be calculated using the Darcy–Weisbach equation shown in 22.4.2.1.3 using a Moody diagram, -factors that are representative of aged pipe, and adjusted K-factors for fluid properties.