NFIP Proper Openings
Proper flood openings, also known as flood vents, are structural elements designed to allow floodwaters to flow freely through enclosures, preventing hydrostatic pressure that could otherwise damage or collapse foundation walls. These openings are a key feature in NFIP rating as they reduce flood risk and may qualify for premium discounts.
Find more details in Technical Bulletin 1.
Requirements
To meet NFIP standards for proper flood openings, the following conditions must be satisfied. Policies that used Legacy rating were required to have documentation that proved the size, location, and placement of proper openings. These documents are no longer required.
Placement
A minimum of two openings must be positioned on at least two exterior walls. In some cases, two openings can be accepted on a single exterior wall adjacent to the lowest grade.
Height
The bottom of all openings must be no higher than one foot above the higher of:
- The exterior adjacent grade.
- The interior adjacent grade or floor below the opening.
Size
The total net area of openings must equal or exceed one square inch per square foot of the enclosed area.
Eligible Foundation Types
Buildings with the following foundation types may qualify for the proper flood openings discount:
- Elevated with enclosure on posts, piles, or piers.
- Elevated with enclosure on solid foundation walls.
- Crawlspaces (elevated or non-elevated subgrade).
Engineered Openings
As an alternative to standard flood openings, engineered openings are certified designs that meet NFIP requirements. One of two types of engineered openings are allowed.
Certification by a licensed professional (e.g., engineer or architect)
Usually for unique creations that do not have an ICC certification. The documentation must show:
- The professional’s license details and signature with an official seal.
- Validation that the openings allow for automatic equalization of hydrostatic pressure.
- Information on tested flood characteristics, such as water rise and fall rates.
International Code Council (ICC) Certified Openings
Products evaluated by the ICC are acceptable if accompanied by documentation showing:
- Number of openings installed
- Square footage covered
- Model number
| Manufacturer | Site Link | Model Numbers | ICC-ES Link |
|---|---|---|---|
| SmartVent | https://www.smartvent.com/ | 1540-520, 1540-521, 1540-510, 1540-510, 1540-510, 1540-510, 1540-510, 1540-510, | |
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