New York City recently became the first jurisdiction in the country to reject and rewrite major sections of the International Building Code’s language around fire protection in exterior façades. Aiming to enhance the fire safety standards in exterior walls, fireblocking is now mandatory behind ventilated cladding, with few exceptions.

The approval of what would be known as the 2022 Construction Codes (the New York City Building Code) came into enforcement in late-2022. The building community quickly recognized the seemingly inadvertent, but effective, ban on the use of previously accepted ventilated façade assemblies.

Without the use of ventilated façades, designers face the challenge of creating exterior walls that effectively manage water over the building’s lifespan while providing the thermal performance needed to meet energy requirements, such as those outlined in the New York City Energy Conservation Code and New York City’s Local Law 97.

Ventilated façades and the high-performance materials utilized in their construction are critical tools in the design and performance of buildings, ensuring that they meet the ever-evolving performance needs of exterior wall assemblies.

For decades, buildings have relied on intumescent materials for fire control. These applications range from fireproofing of structural steel to through-penetration firestopping of mechanical and electrical services to perimeter-edge sealing of fire doors to joint and gap sealing in order to limit fire spread.

These materials have also been used in the exterior cavities of façade assemblies globally for more than two decades. However, they are currently not included in the list of fireblocking materials prescribed in the New York City Building Code.

Intumescent materials, which expand when heated, provide a critical barrier against heat and flame during fire events. These materials have not only proven to be an effective fireblocking solution, but tests have demonstrated that they can also outperform traditionally accepted materials.

Intumescent fireblocking is a simple, safe and effective fireblocking material and, right now, it may be the only tested option that can provide the intended protection during a fire event and maintain rainscreen principles continuously throughout the exterior wall covering. Simultaneously, it enables the design of exterior walls that can meet the other stringent performance requirements imposed on today’s buildings.

Read the full analysis by Antoine Habellion, P.Eng., M.Eng., M.S., and Steven Gaynor, MBA. Their article recently won the 2024 Construction Specifications Institute Article of the Year Award.