K-Factor Calculator for Fire Sprinkler Systems
The K-factor formula is fundamental to hydraulic calculations for fire sprinkler systems. It relates the flow rate through a sprinkler to the pressure at that sprinkler. This interactive calculator allows you to explore the relationship between K-factor, pressure, and flow rate.
Imperial
Metric
L/min/bar^0.5
bar
L/min
Key Points About K-Factor in Fire Sprinkler Systems:
- Definition: The K-factor is a coefficient that represents the discharge characteristics of a sprinkler orifice.
- Standard K-Factors: Common metric K-factors include 57 (Light Hazard), 80 (Ordinary Hazard), 115, and 160. Imperial equivalents are approximately 4.0, 5.6, 8.0, and 11.2 gpm/psi^0.5.
- Relationship: The flow rate (Q) is proportional to the K-factor (K) multiplied by the square root of the pressure (P): Q = K√P.
- Minimum Pressure: NFPA 13 requires a minimum pressure of 7 psi (0.48 bar) at any sprinkler, regardless of the calculated value.
- Design Considerations: Selecting the appropriate K-factor is crucial for achieving the required design density with optimal pressure requirements.
- Unit Conversion: To convert from imperial to metric K-factor, multiply by 14.275 (e.g., K-5.6 × 14.275 = K-80).