How to determine fire flow upper limit?? Is it a random value or have to be calculated by designer or client will be required to provide its value??
Hi Jay,
Fire flow requirements such as pressure and flow are regulated by the fire department and the local water supply body. These organizations define the provisions in standards and codes for flow and pressure at hydrants. Apart from this, several standard manuals and books also have methodology to determine fire flow.
You can refer the standards and codes based on the project area to find out the maximum and minimum fire flow required.
You can refer the Advanced Water Distribution Modeling and Management book for some reference;
Advanced Water Distribution Modeling and Management
Also refer the learning resource guide for additional information on WaterGEMS/CAD.
Learning Resource Guide for new users of Bentley WaterGEMS and WaterCAD
Hope this helps.
Regards,
Yashodhan Joshi
If you are talking about the "Fire Flow (Upper Limit)" field in the fire flow analysis, that is a value that tellsl WaterGEMS, to stop iterating on the solution because the fire flow is more than adequate. Usually you set this slightly higher than the largest Needed Fire Flow in you system.
For example, there may be a node at the intersection of 36 and 48 in. pipes that can deliver a flow of 20,000 gpm but the highest fire flow required is 3000 gpm. Why bother calculating values that are beyond what you need? Usually when you get into that range, available fire flow is limited by hydrant availability and not distribution system capacity.