JPL tests and publishes positive pressure rating in accordance with ADC Test Code FD 72-R1. In the FD 72-R1 pressure and temperature test, the duct is tested in a 90 degree elbow configuration at 140 degrees F for 164 hours and 180 degrees F for four hours at the rated pressure.
Several flex duct manufacturers publish their positive pressure ratings based on the UL-181 Standard Pressure Test. The 181 test configuration is a straight eight foot length with restrained ends.
The duct is tested at 2.5x rated pressure for one hour at ambient (room) temperature.
Some flexible duct manufacturers publish two pressure ratings.
- The higher rated pressures are per the UL-181 test standard
- A second lower rated pressure footnoted as “Recommended”
JPL positive pressure ratings are based on conditions the duct will actually be subjected to, i.e. elbowed (bent) at elevated temperatures for extended periods of time.
When comparing or specifying flexible duct pressures and temperatures, be sure the product data was formulated and presented using the ADC FD 72-R1 test code.