Class A vs. Class C MDC

3S is excited about the recent change to NFPA 2001 – 2011 Edition that differentiates between the minimum design concentrations to extinguish a Class A combustible fire from a Class C energized electrical hazard. 

In most cases we find end users want to keep their data processing and climate conditioning systems running at all times, even in the event of a fire suppression incident.  End users are also especially concerned with inadvertently shutting down process equipment during routine testing and inspecting.  

By recognizing and prescribing a design concentration to common fire suppression agents for energized electrical hazards, the NFPA 2001 Committee has given a tool to the fire suppression contractor to make the  right design decisions for their customer.  Granted, NFPA 75 still has a requirement for providing a power disconnecting means in the hazard however, this does not require an equipment shutdown during a suppression event.