An O-ring (preformed packing) boss has a straight thread. The seal for this termination is a preformed packing
that fits at the top of the threads on the male fitting. This packing is squeezed into the extra space at the top
of the threads of the female fitting and seals the connection. The installed packing must be free of nicks and
cuts to seal properly. If packing is nicked or cut, it must be replaced.
Packing must be located fully into groove and not on threads. Failure to comply may
result in damage to equipment.
A flareless fitting uses a straight thread. The female fitting contains a ferrule that mates with a cavity in the male
fitting. Use recommended torque values in appendix D to tighten nut. If this fitting is overtorqued, the ferrule
will be deformed and the fitting will leak.