Section 6.1.1/Water Supply Requirements
NFPA 13 Chapter 6 covers water supply adequacy, duration, and the hydraulic basis for sprinkler system design.
Every sprinkler system must have a water supply adequate to deliver the system demand (flow rate and pressure) for the required duration. The water supply must be from an approved source (municipal water, fire pump, tank, or combination). A hydraulic calculation must demonstrate that the available water supply pressure and flow exceed the system demand at the base of the sprinkler riser. The minimum duration ranges from 30 to 60 minutes depending on the hazard classification. A fire department connection must be provided.
Why this section exists
A sprinkler system is only effective if the water supply can deliver enough water at sufficient pressure to all operating sprinklers for the duration of the fire. An inadequate supply results in sprinklers that flow less water than designed, potentially failing to control the fire. The hydraulic calculation proves that the supply can meet the demand under the most demanding design scenario.
What plan reviewers look for
Plan reviewers check the sprinkler hydraulic calculation summary for the system demand point (flow and pressure) and the available supply curve. They verify that the supply curve exceeds the demand point with adequate margin. They check the water supply test data (flow test) for date and results. They verify the fire department connection location and the water supply duration.
Common violations
Related NFPA 13 requirements
Section 8.5.1 covers sprinkler spacing. Section 23.1.1 covers hydraulic calculation requirements. Chapter 11 covers the design criteria (density/area) that determines the system demand. Section 6.4 covers fire department connections.