What is one requirement for materials to meet the air barrier standards of most codes?

One requirement for materials to meet the air barrier standards of most codes is that they must not exceed a specific air leakage rate, typically expressed as 0.004 cfm/ft² at a pressure difference of 1.56 ft. of water. This measure ensures that the materials used in air barriers effectively limit the passage of air, which is crucial for maintaining energy efficiency and indoor air quality in buildings. By adhering to this standard, materials contribute to minimizing uncontrolled air infiltration and exfiltration, thus supporting the overall performance of the building envelope.

The other options, while they might be relevant in certain contexts, do not pertain to the primary requirement for air barriers according to most codes. Biodegradability, transparency, and sunlight penetration are not critical factors in determining whether a material qualifies as an air barrier; rather, the focus is on air permeability and how well the material can resist air movement.