This code section 401.5 is for air intake openings, exhaust openings are not included and are addressed in other sections of the code, the code requires all air intake openings regardless of size to comply with this section of code.
In the High Velocity Hurricane Zone (HVHZ) regarding NOA louvers, Section 1626.5.3 Open and closed louvers located on the building envelope, regardless of their function or location from grade, shall also comply with uniform air pressure testing per TAS 202 protocol and either the cyclical wind pressure loading per TAS 203 protocol or by complying with both the impact and cyclical pressure testing of AMCA 540.
