Minimum discharge density, duration, and solution demand for compressed air foam systems (NFPA 11-2021 §8.15–.17)
◉ NFPA 11-2021 §8.15–.17 STYLE CHECK · NOT A REGULATORY SUBMISSION TOOL
⚠ Deliberately small scope. This source PDF has no text layer at all (a pure scan), so this was read directly from page images. Unlike the low-expansion foam chapter (Chapter 5), CAFS design is inherently manufacturer-proprietary: §8.11 and §8.17 explicitly require the system to be designed, and flow calculations performed, per the specific equipment's own listed design manual — there's no universal sizing formula in this chapter to extract. What this tool computes are the two baseline minimums the standard does state directly (§8.15 discharge density, §8.16 discharge duration) and the resulting minimum solution demand. Treat this as a floor to check your manufacturer's actual design against, not a substitute for it.
Identification
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Design Basis (§8.15, §8.16)
For 3-D equipment protected by fixed spray-type systems, §8.15.1 applies the density over the projected area of the rectangular prism envelope enclosing the equipment and its appurtenances — compute that envelope area yourself and enter it above.
Result
Minimum discharge density—
Minimum discharge duration—
Minimum solution flow rate—
Minimum total solution volume—
Beyond these minimums: actual density and duration may be higher per the applicable occupancy standard or the manufacturer's listing (§8.15) — these are floors, not design values on their own. System flow calculations (air/water ratio, piping hydraulics, foam bubble structure preservation) must follow the manufacturer's listed design manual (§8.17.2); no calculation is required at all for a listed pre-engineered system used within its manual's limitations (§8.17.3).