The new International Building Code now allows for the use of weather-resistive barriers above 40 feet high.
Code restrictions had been designed to limit the use of combustible materials that might propagate flames. In the 2015 update, however, exceptions are allowed that recognize that in certain circumstances a weather-resistive barrier by itself would be a negligible contributor to the spread of flames.
This change should result in an energy efficiency boost in cases where builders have had to transition to less efficient methods of weather sealing above 40 feet. Weather-resistive barriers are now allowed in walls in which the water-resistive barrier is the only combustible component and the exterior wall has a fire-resistant wall covering of brick, concrete, stone, terracotta, stucco, or steel.
The material can also be used in walls in which the water-resistive barrier is the only combustible component and the water-resistive barrier has certain heat, flame spread, and smoke properties in accordance with ASTM E 1354 and ASTM E84 or UL723.