As was discussed in Part 1 of this article in the August PME, FM 200 is a halocarbon agent accepted as an alternative to halon for total flooding fire suppression systems. After receiving the fire signal, FM 200 is discharged totally from the cylinders within 10 seconds to fill up the space uniformly at the design concentration to extinguish the fire. The agent is retained at its design concentration in the space for a period-called "Hold Time"-to extinguish the fire. After the fire is extinguished, the agent is exhausted from the space before any inspection is performed.
Several formulas were explained in Part 1 of this article, based on NFPA Code 2001, "Standard on Clean Agent Fire Extinguishing Systems." Those formulas should be used to determine the values for the following calculations for designing a fire protection system using FM 200.