A40, A60, G90 Explained: Be Able To Explain It Like A Pro 07/14/2025|Admin|Resources, Uncategorized Most professionals in the built environment have a general idea what A40, A60, and G90 mean but can you confidently explain it to an architect or contractor which the better choice is for hollow metal doors and frames? Here’s your quick refresher to help … Continue reading A40, A60, G90 Explained!