Fire Safety Calculators | Professional NFPA Tools

Select a calculator above to begin your design or verification work.

Clean Agent / Gas Suppression System Calculator

Calculates required agent quantity (e.g., FM-200, NOVEC 1230) based on room size, temperature, and design concentration (NFPA 2001).

Room Dimensions

Room Length (ft):

Room Width (m):

Room Height (m):

Room Temperature (°F):

Design Parameters

Selected Agent (Affects formula constants):

Design Concentration (%): 7.5% is common for Class A/C hazards using FM-200.

Altitude (ft): Higher altitude requires more agent.

Water Mist System Calculator

Estimates basic water demand for initial system sizing based on hazard area and density requirements (NFPA 750).

Protected Area (Sq Ft):

Required Density (GPM/Sq Ft): Varies greatly by system listing. Example: 0.05 GPM/Sq Ft.

Design Duration (Minutes):

Foam System Calculator (NFPA 11)

Calculates the required foam concentrate volume based on area, application rate, and system duration.

Area of Hazard (Sq Ft):

Application Rate (GPM/Sq Ft): Varies by foam type and hazard. Example: 0.16 GPM/Sq Ft for hydrocarbon.

Design Duration (Minutes):

Foam Concentrate Percentage (%): Enter the mixing percentage of the concentrate.

CO₂ System Calculator (NFPA 12)

Estimates the required CO₂ agent weight for total flooding based on room volume and desired concentration.

Room Dimensions

Room Length (ft):

Room Width (m):

Room Height (m):

Design Parameters

Required CO₂ Concentration (%): Select the concentration based on the hazard class (NFPA 12, Table 4.1.3).

Smoke Detector Spacing Calculator (NFPA 72)

Calculates the **maximum allowable spacing** between spot-type smoke detectors based on ceiling height and type, as required by NFPA 72. **Room length and width are not required** for determining maximum spacing.

Ceiling Height (ft):

Ceiling Type:

Fire Alarm Battery Standby Calculator (NFPA 72)

Calculates the minimum required Amp-Hour (Ah) capacity for fire alarm batteries based on standby and alarm loads and durations.

Current Loads (Amps)

Total Standby Current (Amps): Average total current draw of all devices during normal operation.

Total Alarm Current (Amps): Peak total current draw of all devices during alarm (NAC + Control Panel).

Duration Requirements (NFPA 72)

Required Standby Time (Hours): Minimum 24 hours required for most applications.

Required Alarm Time (Minutes): Minimum 5 minutes required (15 min for voice/mass notification).

Voltage Drop Calculator (2-Wire DC)

Calculates the voltage drop and End-of-Line (EOL) voltage for a fire alarm circuit based on wire gauge, length, and current draw.

Source Voltage (VDC):

Total End-of-Line Current (Amps):

Wire Length (ft - one way):

Wire Gauge (Circular Mils, CM): Resistivity constant K = 10.4 CM-Ohms/ft (copper).

NAC Circuit Load Calculator (NFPA 72)

Calculates the total peak current draw of a Notification Appliance Circuit (NAC) to ensure it does not exceed the panel limit.

Circuit Parameters

Panel Circuit Limit (Amps): Max current allowed by the panel manufacturer (e.g., 3.0A).

Strobe / Horn Load

Number of Strobes/Horns on Circuit:

Strobe/Horn Peak Current Draw (Amps):

Speaker Load (Optional)

Number of Speakers on Circuit:

Speaker Peak Current Draw (Amps): Use the largest speaker's peak current draw.

Fire Stopping Sealant Volume Calculator

Estimates the volume of firestopping sealant required for a single circular penetration.

Opening Diameter (Inches):

Penetration (Pipe/Cable) Diameter (Inches): Enter 0 for a blank opening/annulus.

Required Sealant Depth (Inches): Based on the UL/FM fire-stop listing (e.g., 1 inch).

Fire Door Inspection Checklist (NFPA 80)

A simplified checklist for inspecting the core operational components of a fire door assembly (NFPA 80, 5.2.4).

1. Door Gaps: Are gaps between the door and frame within code limits (typically max 1/8" top/sides, 3/4" bottom)?

2. Latching: Does the door fully latch and remain secured?

3. Self-Closing/Closer: Does the door self-close and latch when opened?

4. Hardware: Are hinges, closers, and other parts securely attached and undamaged?

Fire Damper / Smoke Damper Selection Guide

Provides guidance on the required type and rating of dampers based on barrier type and HVAC system operation (NFPA 90A/IBC).

1. Location/Barrier Type:

2. HVAC System Status in Fire Mode:

Occupant Load Calculator (NFPA 101 / IBC)

Calculates the maximum allowed number of occupants based on floor area and the prescribed occupancy factor.

Floor Area (Sq Ft): Area used for determining occupant load.

Occupancy Type / Load Factor: Factors vary by code edition and specific usage. Consult NFPA 101 or IBC.

Egress Width Calculator (NFPA 101 / IBC)

Calculates the minimum required total width of all exit paths (doors, stairs, ramps) based on the calculated occupant load.

Occupant Load (OL): Use the result from the Occupant Load Calculator.

Type of Egress Component:

System Level: Factors: 0.2" (stairs), 0.15" (other) for reduced capacity; 0.3" (stairs), 0.2" (other) for standard.

Emergency Lighting Spacing Calculator

Estimates the maximum fixture spacing based on mounting height, light intensity, and the minimum required illuminance (simplified inverse square law).

Mounting Height (ft):

Fixture Candlepower (Candela): Light intensity output from the emergency fixture.

Minimum Required Illuminance (ft-c): Typically 1.0 ft-c or 10.76 Lux (NFPA 101/IBC).

Hydrant Flow Calculator (NFPA 291)

Calculates the flow rate from an open hydrant outlet based on the measured velocity pressure (pitot pressure) and outlet diameter.

Pitot Pressure (PSI): Measured velocity pressure using a pitot gauge.

Outlet Diameter (Inches): Internal diameter of the flowing outlet (e.g., 2.5 inches).

Coefficient of Discharge (C): Usually 0.90 for a smooth, well-rounded outlet (NFPA 291).

Friction Loss Calculator (Hazen-Williams)

Calculates the pressure drop due to friction in a pipe run using the Hazen-Williams formula.

Pipe Internal Diameter (Inches):

Flow Rate (GPM):

Pipe Length (ft):

Hazen-Williams C-Factor: 120 for new steel pipe, 100 for black steel, 140 for new plastic.

Required Fire Flow Calculator (NFPA 1142)

Estimates the minimum required fire flow for a structure based on building area and construction type (NFPA 1142 formula).

Building Floor Area (Sq Ft): Total area of all floors for the largest fire compartment.

Construction Type Factor (C): Formula: F = 18 * C * sqrt(Area).

Fire Pump Sizing & Head Calculator

Calculates the minimum required pump head (pressure) based on system demands, losses, and available water supply.

Demand Flow Rate (GPM): Flow required by the sprinkler/hose system (e.g., 500 GPM).

Required Pressure at Remote Point (PSI):

Total Friction & Minor Losses (PSI):

Elevation Head (PSI): Pressure needed to lift water to the remote point (0.433 PSI/ft).

Minimum Available Suction Pressure (PSI): Pressure supplied to the pump from the city water main or tank.

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