NFPA 1142 Water Supply Calculator

Work the minimum water supply for a building without an adequate hydrant. Enter the structure's size, construction, and occupancy hazard and it returns the required water supply per NFPA 1142.

What it does

NFPA 1142 sizes the water supply for rural and suburban firefighting where a reliable hydrant or waterworks isn't available. The tool works the standard's method for you:

• Total structure volume from length, width, and height
• Construction classification factor
• Occupancy hazard classification number
• Minimum required water supply, in gallons

How to use it

1. Enter the structure length, width, and height.
2. Choose the construction type and occupancy hazard.
3. Read the minimum required water supply.

FAQ

What is NFPA 1142?

NFPA 1142 is the Standard on Water Supplies for Suburban and Rural Firefighting. It provides a method for determining the minimum water supply needed for manual firefighting where hydrants or a public waterworks are not available.

When do you use NFPA 1142 instead of NFPA 13?

NFPA 1142 addresses the water supply available for firefighting a structure that is not protected by an automatic sprinkler system with an adequate supply. It is not a substitute for an NFPA 13 hydraulic design; it answers a different question.

Is this an official calculation?

It applies the NFPA 1142 method to your inputs to give a fast, documented estimate. Always verify against the current edition of the standard and the authority having jurisdiction.