Does anyone know if this is code?

I moved into a single family house in Massachusetts and have an automatic fire sprinkler system that is about 10 years old. The pipes are cast iron and run up to the attic, then spread out across the tops of the ceiling joists & feed down to the living area ceiling sprinkler heads below.

The pipes are not insulated and the attic is not heated, so I'm concerned about them freezing in the winter.