At Catalina Cylinders, the minimum number of threads required is based on information from Fed Standard H-28. Fed Standard H-28 is referenced directly in 49 CFR 178.46; DOT-3AL. The minimum number of threads required in a SCUBA cylinder with �-14 NGS threads varies depending on the service pressure. Listed below are the minimum number of threads required for aluminum SCUBA cylinders with �-14 NGS threads at different service pressures as calculated by Catalina Cylinders.
Service Pressure
Minimum # of Threads
3000 psi
8.0
3300 psi
9.0
3500 psi
9.0
Note: The minimum number of threads is rounded up to the next complete (whole) thread.