HomeMy WebLinkAboutFile Documents.1265 Red Butte Dr.0032-2023-BCHO (4)
PO BOX 8610 • AVON, CO 81620 • Telephone 970-845-7910
Fax 970-845-7522 • E-mail drader@raderengineering.co
06/21/2023
Mr. Carlos Rodríguez
Timberline Construction
204 Park Ave. Ste 2D
Basalt CO. 81621
Via email: carlos@timberlineconstruct.com
RE: Fenestration Calculations
1265 Red Butte
Aspen, CO 81611
REI Job No. 23018.00
Carlos,
Per your request, we have updated the fenestration calculations for the 1265 Red Butte project
with a 2-pane window. Calculations for non-NFRC rated assemblies are performed per
ASHRAE Fundamentals 2021, Chapter 15 “Determination of Fenestration U-Factor”. Refer to
the attached Appendix I for the Fenestration Performance Calculations.
Results:
Total Weighted Assembly U-Value = 𝟎.𝟐𝟖 𝑩𝑻𝑼
𝒉𝒓∙𝒇𝒕𝟐∙°𝑭
Method:
Determine the U-Value for three sections of each fenestration assembly separately.
o Center of glass (Ucg)
o Edge of glass (Ueg)
o Window frame (Uf)
Divide fenestration assembly into appropriate sections.
Calculate the weighted average U-Value (UT), by area, of the three sections for each
fenestration assembly.
𝑈் =ಸ ಸାಶಸಶಸ ାಷಷ
Assumptions & Provided Information:
All glass geometries are taken from the email correspondence on 06/20/2023 and Plans
dated 10/05/2022.
The Center of Glass U-Values were calculated using the Lawrence Berkeley National
Laboratory Window 7.8 software program.
o Ucg-Value for the Cardinal 6mm LoE366-6.CIG-i89-6.CIG assembly is
0.224 ்
∙௧ మ ∙°ி
The edge of glass is considered to be the glass within 2” of the frame and divider.
The Edge of Glass delta for the U-Value was interpolated from data in ASHRAE Table
4, page 15.9 and corresponding center of glass information.
o Ueg-Value for the Cardinal 6mm LoE366-6.CIG-i89-6.CIG assembly is
0.379 ்
∙௧ మ ∙°ி
The U-Values for the frame type, vertical orientation were provided by ASHRAE
Table 1, page 15.6 as a data for extrapolation was not available.
o Uf-Value for wood frame with thermal break is 0 .480 ்
∙௧మ∙°ி
6/21/23
Signature (Rader Engineering, Inc.) Date:
Appendix I
Page 1 of 1
Job Name: 1265 Red Butte
Job #: 23018
Date: 06/21/2023
Calcs By: B.G.K.
Assembly
Window Assembly Fixed Cardinal 6MM Double 366-Clear-i89 2 81 107 17,334 68 95 12888 0.224 1335 0.379 3,112 0.480 0.28
120 0.28
1. Rader Engineering Inc. Disclaimer: The above U-Factors were determined using the methods in the 2017 ASHRAE Handbook,
values are calculated estimates. The above window was NOT formally tested by the NFRC.
U-Value
UT
Assembly Area (ft.2)Calculated Assembly Area Weighted U-Value
Width
(in.)
Height
(in.)
Area ACG
(in.2)
U-Value
UCG
Area AEG
(in.2)
U-Value
UEG
Unit ID Assembly Type Nom. W
(in.)
Nom. H
(in.)
Area AT
(in.2)
Edge of Glass TOT Frame TOT
Area AF
(in.2)
U-Value UF
ASHRAE Fenestration Performance Calculations
(Refer to Chpt. 15 of 2021 Fundamentals ASHRAE handbook)
Assembly PANEL TOT Center of Glass TOT
QTY OF PANELS