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Fire flow analysis with EPANET

Calculate fire flows in your EPANET hydraulic model. https://utils.epanetjs.com/fire-flow - you can do it yourself here! In fire flow studies, you’re usually checking two things at a junction: 1. The required fire flow (e.g., 50 L/s or 1500 gpm) 2. The minimum residual pressure you must maintain (e.g., 20 m or 20 psi) To answer those questions properly, we run three different simulations: 𝐀𝐯𝐚𝐢𝐥𝐚𝐛𝐥𝐞 𝐅𝐢𝐫𝐞 𝐅𝐥𝐨𝐰 This is the maximum flow the network can supply at that location before the pressure drops below the required residual pressure. For example, if the minimum allowable pressure is 20 m and the model shows you can take 86 L/s before hitting that threshold, then 86 L/s is your available fire flow. 𝐍𝐞𝐞𝐝𝐞𝐝 𝐅𝐢𝐫𝐞 𝐅𝐥𝐨𝐰 If your required fire flow is lower than the available fire flow, we run another simulation at the required value. This tells you what the residual pressure actually is during a real-world design flow. Both the available and need fire flow checks are entirely local - it's about what the system can deliver right there at that junction, independent of larger system constraints. 𝐃𝐞𝐬𝐢𝐠𝐧𝐞𝐝 𝐅𝐢𝐫𝐞 𝐅𝐥𝐨𝐰 This is the simulation most people forget - and it’s the most important. It looks at the entire network to ensure that running a fire flow at the selected junction doesn’t break constraints anywhere else. The classic example: Testing a hydrant at the bottom of a hill. At the bottom of a pressure zone, pressures are typically much higher, so the available fire flow may be very large - sometimes unrealistically large. But pulling that much flow can significantly drop pressures upstream or higher in the zone, potentially pushing parts of the system below minimum pressure. Designed Fire Flow checks for exactly this: • Does any other junction fall below the minimum pressure? • Do any pipes exceed maximum velocity limits (e.g., 2-4 m/s or 10 ft/s)? • Is this fire flow realistic for the network as a whole? If constraints are violated, the model automatically iterates to find the maximum system-wide allowable fire flow - not just the local one.