What percentage of the design pressure or pressure relief device setting must joints in air ducts withstand?

Joints in air ducts must withstand a pressure that is 150 percent of the design pressure or the setting of the pressure relief device. This requirement is in place to ensure safety and to account for any potential surges in pressure that could occur during system operation.

By requiring the joints to be able to withstand this greater pressure, the likelihood of failure or leakage is reduced, which can help maintain the integrity of the air distribution system and prevent issues like cross-contamination between spaces or loss of efficiency.

The standards are selected based on industry best practices and provide a robust safety margin to ensure that systems can operate reliably under varying conditions. In comparison to the other options, 150 percent is the standard that has been established to address potential safety concerns effectively.