The BPI energy auditor training course prepares individuals to understand the various components of building science, including combustion safety, blower door testing, energy analysis, and home performance assessments.
Key difference: The two paper sizes are used for different purposes in different countries. A4 paper is part of 'ISO 216-series' , while the Letter paper is a part of the old 'American National Standard Institute'. A4 is an internationally recognized paper size that measures 8.27 inches wide and 11.69 inches tall. All âAâ sizes has an aspect ratio of 1: â 2 (square root of 2).
Note that a mail piece is a flat if it meets at least one of those requirements. It does not need to meet all of them. So if your piece is larger or thicker in any allowable dimension to be a letter, and is not larger or thicker than the maximums for flats, it is a flat, even if it fits the other dimensions for a letter.