The short answer
- NAFS is the joint US-Canadian-Mexican fenestration standard that sets structural and water-resistance performance grades for windows and doors, referenced by building codes in both the US and Canada.
- A Performance Grade (PG) number combines the design pressure tested, a product-type code (residential, light commercial, commercial, or architectural), and the size of the test specimen into one rating.
- The same PG number means different things by product class: PG50 tested on a commercial-window class is a more demanding test than PG50 on a residential class.
- NAFS rates structural and water-resistance performance only; a separate standard covers energy performance such as heat loss and solar heat gain, and many jurisdictions require both for code compliance.
How to read a PG rating.
A PG rating combines the test pressure (e.g., PG50 = 50 psf design pressure), the product type code (R for residential, LC for light commercial, CW for commercial windows, AW for architectural windows), and the size of the test specimen. PG50 on a CW (commercial window) class is a more demanding test than PG50 on an R (residential) class.
Typical residential coastal projects spec PG50 minimum. Multifamily and high-rise commercial spec CW-PG50 to AW-PG70. Hurricane-zone projects spec PG70+ with separate impact testing. Crateworks confirms PG requirements per project before order.
Common questions.
- Is NAFS required by code?
- Yes in most US jurisdictions. The IBC references NAFS for structural performance, and the Canadian NBC references NAFS for fenestration. Permit sets in both countries typically require a NAFS PG rating on the product schedule.
- What is the difference between NAFS and NFRC?
- NAFS rates structural and water-resistance performance (PG). NFRC rates energy performance (U-factor, SHGC). The two are separate test programs; a window can carry both ratings, and most jurisdictions require both for residential code compliance.
- What PG rating do I need?
- Depends on building height, exposure category, and jurisdiction. Single-story coastal residential typically PG50. Multifamily and high-rise commercial PG70 to PG100. Hurricane wind zones layer in separate impact testing requirements on top of the PG rating.
Keep reading.
Project in motion
Need NAFS-rated product?
We work with NAFS-tested configurations across the catalog. Confirm the project PG requirement at quote.