Note: Numbering is based on SI edition of ASHRAE 90.1-2013. Version 1 - May, 2017
Section 5.5 Overall Building Design Requirements
The building design must comply with the following general requirements. If any of these requirements are not met, the prescriptive
path cannot be pursued. Consider the building envelope trade-off compliance or the Energy Cost Budget Method Described in
Chapter 11 of ASHRAE 90.1-2013:
Gross Wall Area: _________ m²
Vertical Fenestration Area: _________ m²
Vertical fenestration area is less than 40% of the gross wall area
Gross Roof Area: _________ m²
Skylight Area: _________ m²
Total skylight area does not exceed 3% of the gross roof area
Where the main entrance is located on the south orientation and the south-oriented wall area
is larger than west-oriented wall area, and where the south-oriented wall area is larger than
east-oriented wall area, per ASHRAE 90.1-2013 5.5.4.5, either:
(a) total east and west vertical fenestration areas are each less than 25% of total vertical
fenestration area for the whole building, or
(b) east and west area-weighted SHGC is less than area-weighted SHGC for total
fenestration
Exception (from ASHRAE 90.1-2013 Section 5.5.4.5): ______________________________
Where electric space heating provides more than 10 per cent of the heating capacity, the
building envelope shall comply with the requirements of Table SB 5.5-7 of SB-10, regardless of
its climatic location
For Climate Zone 5, minimum skylight fenestration area conforms to the requirements of
ASHRAE 90.1-2013 5.5.4.2.3.
Identify SB-10 Table used for maximum U-Factors or minimum RSI-Values : _____________
Complete the table on Form 5.5-2 to show compliance for all envelope components. Attach as many copies of this form as required
to ensure that all envelope components are represented.
For all opaque surfaces, compliance must be demonstrated by meeting either:
1. The minimum R-values of insulation added in framing cavities and continuous insulation as specified in Tables SB5.5-5 to
SB5.5-7.
2. The maximum U-factor, C-factor, or F-factor for the entire assembly as specified in Tables SB5.5-5 to SB5.5-7. U-factor is to be
determined from tables in Appendix A of ASHRAE 90.1-2013 or through calculation methods described in ASHRAE 90.1-2013
Appendix Section A9.
For all fenestration products, compliance with U-factors, SHGC and VT must be determined for the overall fenestration product.
1. Fenestration shall have a U-factor and SHGC not greater than those specified in SB-10 Tables SB5.5-5 to SB5.5-7.
2. Where automatic daylighting controls are required in accordance with Section 9.4.1.1(e) or (f), fenestration shall have a ratio
of VT divided by SHGC not less than that specified in Tables SB5.5-5 through SB5.5-7 for the appropriate fenestration area.
3. U-factor to be determined through CSA or NFRC rating or by using ASHRAE 90.1-2013 Appendix A default values.
ASHRAE 90.1-2013 & SB-10 – SECTION 5.5 – PRESCRIPTIVE ENVELOPE OPTION Form 5.5-1