Start from the list of protected spaces, then check that the gas and water supplies, piping, emitters, enclosure details, and release controls on each discipline’s drawings serve the same spaces. AI can flag conflicts; the system designer, the manufacturer’s listed design data, and the authority having jurisdiction decide compliance.
What does NFPA 770 cover?
NFPA 770 is the Standard on Hybrid (Water and Inert Gas) Fire-Extinguishing Systems. NFPA’s official page lists NFPA 770 as the standard on hybrid (water and inert gas) fire-extinguishing systems. Check the scope chapter of the edition you hold for the systems and occupancies it covers.
NFPA’s official NFPA 770 page identifies the 2026 edition as current when checked on October 10, 2026. Confirm the edition, local amendments, and project scope that actually govern the work. The publisher’s newest edition does not establish local adoption.
Hybrid systems combine features that reviewers usually see in two separate packages: the NFPA 750 water mist guide and the NFPA 2001 clean agent guide. Systems are typically designed from a listed manufacturer’s manual, so record the system, the manual edition, and the protected spaces before comparing.
Gather the system drawings and the spaces they protect
Collect the hybrid system layout and isometrics, the gas cylinder and water supply arrangement, the emitter or nozzle schedule, the manufacturer’s data sheets, the architectural plans and sections of each protected space, the door and opening details, the mechanical drawings with dampers and shutdowns, the fire alarm and release control drawings, and the specifications.
System suppliers often issue their drawings late. Upload the current architectural plans with the supplier’s set so each protected space can be compared with the room it actually is.
Match each protected space to its supplies and controls
| Review question | Sources to compare | Decision to record |
|---|---|---|
| Protected spaces | System layout, architectural plans, room names | Confirm each protected space has the same name and boundary on the system and architectural drawings. |
| Gas and water supplies | Cylinder and supply arrangement, plumbing plans, equipment rooms | Check that the supply equipment is drawn in the same room on every sheet and has space shown. |
| Piping and emitters | Isometrics, emitter schedule, reflected ceiling plans | Find emitters whose locations differ between the system drawings and the ceiling plans. |
| Enclosure openings | Door schedule, wall types, mechanical dampers | Ask the designer to confirm how openings and dampers in each space are closed when the system releases. |
| Release and shutdown | Fire alarm drawings, sequence of operations, mechanical controls | Match the release, warning, and equipment shutdown sequence across the fire alarm and mechanical documents. |
| Listed design data | Manufacturer manual, data sheets, specifications | Identify specifications that name a different system or manual from the supplier drawings. |
Detection and release controls follow the NFPA 72 guide. These systems appear in data centers and industrial spaces; the fire sprinkler checklist helps track supply and piping questions.
Example: a protected room that gained a doorway
Hypothetical example. A revision adds a second doorway to a turbine enclosure protected by a hybrid system. The architectural plans and door schedule show the new opening, while the system supplier’s drawings and the release sequence still describe the enclosure with a single door.
The architectural plans and door schedule add a second doorway to the protected enclosure, but the hybrid system drawings and release sequence still describe one door. Please confirm how the new opening is addressed and coordinate the system design and controls.
The system designer reviews the change against the listed design data and reissues the drawings. Compliance is decided by the designer and the authority having jurisdiction.
Review a hybrid system package with Groundbook
Upload the current project PDFs and relevant specifications to Groundbook. Identify the governing issues and add the applicable NFPA 770 reference from a copy you are licensed to use, where the license permits uploading it. State the edition, amendments, review area, and known exclusions in your instructions.
Compare the hybrid system layout and isometrics, supply arrangement, emitter schedule, manufacturer data, architectural plans and sections, door schedule, mechanical drawings, fire alarm and release control drawings, and specifications. Flag protected spaces, supplies, emitters, openings, and release sequences that differ between sources. Use the supplied NFPA 770 edition where applicable and cite both sources.
Groundbook links each potential finding to the sheets involved and the reference you uploaded.
Document review does not perform flow or agent calculations, verify a listing, or approve the system. Those decisions remain with the system designer and the authority having jurisdiction.