The Public Safety Forum (SAFETY)

[Bird of Prey]

According to NFPA 13 Pre-fab rafters are rated the same as gusset-plated rafters. However, due to the solid obstruction they present (as opposed to the open style of gusset-plated rafters) the spacing rules for fire sprinkler protection are more restrictive.
Depending on the configuration and type of sprinkler used the pre-fab truss could require a greater number of sprinklers to achieve the same level of fire protection compared to an identical structure with gusset-plated trusses.

Having designed several Fire Sprinkler systems where pre-fab trusses were used between floors, I can say that the systems did not have significantly more sprinklers than they would have using standard trusses.

The Bird of Prey