NA6.2      Default U-factor

 

Equation NA6-1

UT= C1 + (C2 X Uc)

 

Where:

UT = U-factor  Is the Total Performance of the fenestration including glass and frame

C1 = Coefficient selected from Table NA6-5

C2 = Coefficient selected from Table NA6-5

UC =  Center of glass U-factor calculated in accordance with NFRC 100 Section 4.5.3.1 www.nfrc.org/software.aspx

 

Table NA6-5 – U-factor Coefficients

Product Type

Frame Type

C1

C2

Site-Built Vertical Fenestration

Metal

0.311

0.872

Metal Thermal Break

0.202

0.867

Non-Metal

0.202

0.867

Skylights with a Curb

Metal

0.711

1.065

Metal Thermal Break

0.437

1.229

Non-Metal

0.437

1.229

Skylights with no Curb

Metal

0.195

0.882

Metal Thermal Break

0.310

0.878

Non-Metal

0.310

0.878