ASCE 24-14 is the 2014 edition of the Flood Resistant Design and Construction standard, developed by the American Society of Civil Engineers (ASCE). It replaces the 2005 edition (ASCE 24-05) and introduces significant updates to improve clarity, address emerging challenges, and align with modern building practices. Key differences include the introduction of the Flood Design Class concept, clarified requirements for flood openings, and updated provisions for coastal high hazard areas.

The most notable updates in ASCE 24-14 include:

1. Flood Design Class: Introduced to replace Risk/Occupancy Classification. Structures are now categorized into Flood Design Classes (1–4) based on their risk and importance.
2. Clarified Coastal Zone Requirements: Provisions for Coastal A Zones and V Zones have been refined to improve consistency and reduce confusion.
3. Updated Material Requirements: Enhanced requirements for flood damage-resistant materials to ensure durability in flood-prone areas.
4. New Parking Structure Section: Added specific requirements for multistory parking structures in flood hazard areas.

Flood Design Class replaces the Risk/Occupancy Classification system from previous editions. It categorizes structures into four classes based on their function, risk, and importance:

• Class 1: Low-risk structures (e.g., agricultural buildings).
• Class 2: Standard-risk structures (e.g., residential buildings).
• Class 3: Higher-risk structures (e.g., schools, assembly spaces).
• Class 4: Critical facilities (e.g., hospitals, emergency shelters).

Each Flood Design Class has specific elevation requirements for lowest floors, equipment, and flood-resistant materials. For example, critical facilities (Class 4) must be elevated or protected to a higher standard than standard-risk structures (Class 2).

ASCE 24-14 clarifies Coastal A Zone requirements by:

• Allowing shallow foundations under certain conditions.
• Requiring designs to account for local scour and erosion.
• Mandating flood openings in breakaway walls to allow water flow without structural damage.

For V Zones (coastal high hazard areas):

• The orientation of the lowest horizontal structural member is no longer a factor in determining elevation requirements.
• Substantial improvements of existing buildings seaward of mean high tide are now allowed under specific conditions.

ASCE 24-14 specifies two methods to meet flood opening requirements:

1. Non-engineered Openings: Require one square inch of opening per square foot of enclosed area. No certification is needed.
2. Engineered Openings: Must be certified by a registered design professional and account for louvers, screens, or other coverings.

Dry floodproofing provisions have been expanded:

• New definitions clarify "Mixed Use" and "Residential Portions of Mixed Use" properties to limit where dry floodproofing can be applied.
• Emergency escape and rescue opening requirements have been clarified for dry floodproofed buildings.

The standard now provides explicit guidance on:

• Shallow foundations in Coastal A Zones under specific conditions.
• Structural fill stability during flooding events like rapid rise/drawdown or prolonged inundation.

ASCE 24-14 clarifies requirements for garages, carports, and accessory storage structures:

• Garages below elevated buildings must comply with wet floodproofing standards.
• A new section addresses multistory parking structures located in flood hazard areas.

The standard consolidates all requirements related to nonstructural concrete slabs into one section, simplifying compliance.

Requirements for tanks located in flood hazard areas have been consolidated and clarified to distinguish between different types of tanks based on their function and location.

Swimming pools must meet one of the following criteria:

1. Be elevated above the design flood elevation.
2. Be designed to break away without causing damaging debris during flooding events.
3. Remain in place without obstructing water flow that could cause damage

ASCE 24-14 updates material standards to ensure durability during floods, including resistance to prolonged water exposure, erosion, and scour.

ASCE 24-14 ensures consistency with NFIP regulations while providing additional specificity and stricter requirements where necessary.

While not primarily focused on energy efficiency, the standard ensures that energy-related equipment installed in flood hazard areas is protected from potential damage during flooding events.

ASCE 24-14 has been adopted by reference into model building codes like the International Building Code (IBC). Jurisdictions using these codes require compliance with ASCE 24 standards for structures in flood hazard areas. This FAQ highlights the key changes introduced in ASCE 24-14 Flood Resistant Design and Construction, providing clarity on its updates compared to previous editions while emphasizing its role as a critical resource for designing resilient structures in flood-prone areas.