Pipe vs. Tube - Pipe Nipples for Sprinklers Below Ceiling

[Haldorson]

In NFPA 13 (1999) 5-13.20.3 "Piping to Sprinklers Below Ceilings" (found in the Special Situations section of the Installation Requirements) it states that in areas subject to earthquakes the use of nipples less than 1" in diameter is not permitted to feed sprinklers below the ceiling.

I have a situation where an existing highrise is using 3/4" diameter copper tube nipples to feed sprinklers below the ceiling.

Does the fact we have copper tube and not steel pipe in this situation ease us of this 1" requirement?


Thanks.

 

[AZsprink]

I think NFPA is referring to threaded branch outlets, and not to copper or cpvc type systems. I would think that copper and plastic would be more flexible than threaded steel. Maybe someone with more knowledge than me can chime in. I know that small threads are more apt to break than soldered or glued joints.