Gas Line BTU Demand Calculator
Calculate the total BTU/hr gas demand for your kitchen equipment and estimate the required gas line size (based on low-pressure natural gas supply, 0.5 in. water column pressure drop).
System Parameters
Appliance BTU Inputs
Enter the maximum input BTU/hr rating and quantity for all gas-powered appliances.
How It Works
This calculator determines the required gas pipe size based on your kitchen appliances’ total BTU demand, pipe length, and diversity factor.
Key Formulas Used
1. Total Connected BTU Demand
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Total Connected BTU/hr = Σ (Appliance BTU/hr × Quantity)
This sums the maximum BTU ratings of all connected appliances.
2. Maximum Design Demand (With Diversity)
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Design Demand = Total Connected BTU/hr × (Diversity Factor ÷ 100)
The diversity factor accounts for the fact that not all appliances operate simultaneously at maximum capacity.
3. Pipe Sizing Logic
The calculator compares your Design Demand against NFPA 54/IFGC pipe capacity tables to find the minimum pipe diameter that can handle the load at your specified pipe length.
Simplified Sizing Table (Natural Gas, 0.5″ w.c. pressure drop):
| Pipe Size | Capacity at 50 ft (BTU/hr) |
|---|---|
| 1/2″ | 48,000 |
| 3/4″ | 102,000 |
| 1″ | 185,000 |
| 1 1/4″ | 350,000 |
| 1 1/2″ | 485,000 |
| 2″ | 920,000 |
Important Notes
- Calculations are based on Natural Gas with specific gravity of 0.60
- Uses 0.5 inch water column pressure drop (typical for low-pressure systems)
- Pipe lengths are total developed length (actual pipe run plus fittings allowance)
- Always consult local codes – this tool provides preliminary sizing only