Your dry-pipe or preaction system piping may look brand new on the outside, but what about inside? Residual water and oxygen in the pressurized air could be rusting the interior of that pipe right now. This rust can weaken the pipe, cause pinholes to form, and even clog up the sprinkler heads in the event of a fire. NFPA 25 – Standard for the Inspection, Testing and Maintenance of Water-Based Fire Protection Systems mandates internal inspection of sprinkler pipes at least every 5 years. Are your pipes rusty? Have them internally inspected by a qualified fire protection contractor before it’s too late.