Types of Flood Vents

WARNING: Any louvers, blades, screens, and faceplates or other covers and devices should be selected or specified so as to minimize the likelihood of blockage by small debris and sediment. Where experience has shown that a particular device or type of device has been blocked or clogged by flood debris or sediment, use of such devices should be avoided." - ASCE 24-14 Pg.45 (commentary)

unacceptable measures
Photo Credit: FEMA Technical Bulletin - 1: Page 19


There are Two Types of Flood Vents:

Engineered Flood Openings
Non-Engineered Flood Openings
engineered non engineered

Engineered Flood Openings are designed and certified by a registered design professional as meeting required regulations, performance standards, and design guidelines.

Engineered openings have been designed and tested as flood vents and are given a flood coverage rating based on performance.

To view FEMA's documentation on how Engineered Flood Openings are classified.

Non-Engineered Flood Openings are all other venting designs that are not created for flood venting and have not gone through any of the required testing, or any sort of flood testing for that matter, to qualify as an engineered flood vent. They typically are solely intended for use as an air vent. Therefore, they are rated at the assumptive method of 1 net sq. inch of opening per 1 foot of enclosed area.

To view FEMA's documentation on how Non-Engineered Flood Openings are classified.