The operating room combines oxygen-enriched atmosphere, electrocautery sparks and alcohol-based skin prep into a surgical fire. The US reports 550-650 OR fires per year. NFPA 99 (Health Care Facilities Code) defines oxygen concentration limits, ignition-source control and personnel training.
Surgical Fire Triangle
- Oxidizer: O2 or N2O (100 percent O2 atmosphere)
- Ignition: electrocautery (Bovie), laser, fiber optic
- Fuel: alcohol prep, drape, patient hair, alcohol-based disinfectant
- All three together ignite in 1-3 seconds
Oxygen-Enriched Atmosphere
- Normal O2: 21 percent
- Oxygen-enriched: >23.5 percent
- OR face mask: accumulates under drape - 80-100 percent
- Solution: endotracheal tube or laryngeal mask
- Minimum FiO2: 30 percent suffices for sedation
NFPA 99 Medical Gas Rules
- Gas storage: detached building, 6 m separation
- Copper pipe: Type K or L, no oil-lubricated work
- Zone valve: per OR, shut-off at door
- Pressure alarm: line +/- 20 percent
- Area alarm: control center + corridor
Ignition Source Management
- Electrocautery: O2 off, 3-min dry time after alcohol prep
- Laser ETT: laser-resistant tube (Mallinckrodt Lasertubus)
- Defib pad: dry - no wet alcohol
- Fiber optic: keep active tip away from drapes
Emergency Response
- Step 1: cut O2 (anesthesiologist)
- Step 2: lift drape, douse burning cloth with water
- Step 3: patient secured, then CO2 extinguisher (5 lb mandatory in OR)
- Training: annual OR fire drill - NFPA 99 18.5.2
MEP Calc — 86+ Engineering Calculators
MEP Calc bundles 86+ engineering modules in one iOS app: 21 fire calculations (sprinkler, fire pump, FM-200 clean agent) plus heating, cooling, HVAC, plumbing, steam and natural gas. Download it on the App Store.
Download MEP Calc on the App Store
SprinkCalc — Fire Sprinkler Design Across Three Standards
SprinkCalc covers hazard classification, design density and area, K-factor selection, water demand and hydraulic calculations for NFPA 13, FM Global and BS EN 12845 in a single iOS app, and exports a professional PDF report. One of the few tools that unifies all three major fire protection standards.
Download SprinkCalc on the App StoreNFPA 99, ECRI Institute Surgical Fire Prevention, APSF, AORN Fire Safety Toolkit. NFPA 99 Health Care Facilities standard.