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NFPA 13
Validated against the standard.
PDF export
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$2.99 Pro
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How it works
Enter your values
Type in your inputs — the app fills code tables and constants for you, so there's nothing to look up.
Get a code-checked result
Instant answer with a clear PASS / FAIL and the exact NFPA 13 reference behind every number.
Save & export
Keep a history of calculations and export a clean PDF report to share or attach to a permit (Pro).
What this calculator does
The pipe schedule method is the non-hydraulic way to size sprinkler pipe: each pipe size may serve up to a set number of sprinklers for a given hazard. This app returns those limits from NFPA 13, useful for small light- and ordinary-hazard systems and for quick checks.
Light-hazard example limits
| Pipe size | Max sprinklers |
|---|---|
| 1 in | 2 |
| 1-1/4 in | 3 |
| 1-1/2 in | 5 |
| 2 in | 10 |
| 2-1/2 in | 30 |
| 3 in | 60 |
Ordinary-hazard schedules allow fewer sprinklers per size on the larger pipes; the app switches tables by hazard class.
Worked example
A light-hazard branch with 5 heads needs at least 1-1/2 inch pipe; add a sixth head and it must step up to 2 inch under the schedule.
Related calculators
For larger systems use the sprinkler hydraulic calculator, and support the pipe with the hanger spacing calculator.
Pipe schedule FAQ
When can the pipe schedule method be used?
NFPA 13 permits pipe schedule sizing for certain light- and ordinary-hazard systems, often where they connect to an adequate water supply. Larger or special systems require hydraulic calculation.
Does hazard class change the limits?
Yes. Ordinary hazard allows fewer sprinklers on the larger pipe sizes than light hazard, so the app uses the correct table for the class.
Is hydraulic calculation more efficient?
Usually. Hydraulic design often yields smaller pipe than the schedule, which is why most modern systems are hydraulically calculated.
Does it work offline?
Yes, it runs 100% offline with no account. Free with rewarded ads; a one-time $2.99 Pro unlock adds PDF export and saved history.
Get Pipe Schedule on your phone
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