I have been utilizing a max. velocity constraint (15 ft/s) when running fire flow simulations in InfoWater. The idea is that velocities in excess of 15 ft/s would cause a main failure in the "real world".

The use of a max. velocity constraint has left the office divided. On occasion we are seeing drastic differences in fire flow simulation results between using the constraint and not. This is especially evident in older areas of our distribution system where we have smaller diameter mains with high modeled roughnesses.

I'm wondering what others are doing when running a fire flow simulation? Are you using a max. velocity constraint, or not?

Chris Hathaway
Service Provider for Citizens Energy Group
Indianapolis, IN