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FL Gas Line Sizing & BTU Demand Calculator

NFPA 54 / FPC §409 sizing tables, meter selection, and FL permit requirements

NFPA 54 · FPC §409 · Natural Gas & Propane · FL Permit Ready
📋Appliance BTU Demand Calculator
Check each appliance you have or plan to install. Edit BTU values if you know your model's exact rating. The total determines your gas line and meter sizing.
Select your appliances & verify BTU ratings
💧 Water Heating
❄️ HVAC
🍳 Kitchen
👕 Laundry
⚡ Generator
🌿 Outdoor / Other
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Total design BTU/hr demand
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Installed BTU/hr (all appliances)
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Design CFH (natural gas)
Next step: Take your design BTU/hr to the Line Sizing tab to get recommended pipe diameter per NFPA 54 / FPC §409.
📖Appliance BTU Reference Chart
ApplianceTypical BTU/hrNotes
Tankless WH — condensing150,000–199,000Check nameplate
Tankless WH — non-condensing120,000–150,000High demand
Storage WH (40 gal)32,000–40,000FHR affects size
Storage WH (50 gal)36,000–50,000Most common FL
Storage WH (75 gal)60,000–75,000Large household
Gas Furnace40,000–150,000Per nameplate
Gas Range (5-burner)55,000–65,000All burners + oven
Gas Cooktop (4-burner)36,000–48,000No oven
Gas Dryer (standard)22,000DOE standard
Gas Dryer (high-cap)30,000–35,000DG series
Generator — 10 kW125,000–145,000At full load
Generator — 16 kW175,000–195,000Very common FL
Generator — 22 kW (Generac)245,000–260,000Standard Generac
Generator — 26 kW305,000–330,000Full home backup
Pool/Spa Heater — 200 MBH200,000Typical FL pool
Pool/Spa Heater — 400 MBH400,000Large pool/spa
Outdoor Grill40,000–60,000Estimate
Gas Fireplace / Logs25,000–80,000Per insert
Gas Boiler / Hydronic80,000–175,000Per rating
Gas Space Heater20,000–30,000Wall/floor mount
📐Gas Pipe Sizing — NFPA 54 / FPC §409
Enter your design BTU demand and longest pipe run to get recommended pipe diameter. Based on NFPA 54 Table 402.4(2) for Schedule 40 metallic pipe at 0.3 in. WC pressure drop.
Tip: For sizing purposes, add 50% to actual pipe length to account for fittings (elbows, tees, valves). This is the "equivalent length" method per NFPA 54 §6.1.2.
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Recommended minimum pipe diameter
Always size up: NFPA 54 requires you select the pipe size whose capacity equals or exceeds your design demand. When in doubt, go one size larger — oversizing gas pipe is safe; undersizing causes pressure drop, appliance starvation, and failed inspections.
📊NFPA 54 Pipe Capacity Table — Schedule 40 Steel
BTU/hr capacity at 0.3 in. WC pressure drop · Natural gas (1,020 BTU/cu ft)
Pipe Size 20 ft 40 ft 60 ft 80 ft 100 ft 150 ft 200 ft
1/2″119,00084,00068,00059,00052,00042,00037,000
3/4″255,000178,000145,000127,000111,00090,00079,000
1″476,000332,000273,000238,000209,000168,000146,000
1-1/4″987,000687,000562,000491,000428,000347,000303,000
1-1/2″1,482,0001,032,000845,000738,000643,000522,000456,000
2″2,831,0001,971,0001,613,0001,410,0001,226,000996,000869,000
2-1/2″4,897,0003,410,0002,791,0002,440,0002,122,0001,724,0001,503,000
3″9,163,0006,380,0005,222,0004,564,0003,970,0003,226,0002,814,000
Propane (LPG): For propane, multiply BTU capacity values by 0.406 (propane has higher BTU/cu ft so same volume at same pressure drop carries proportionally less compared to NG sizing tables based on CFH). Use NFPA 54 Table 402.4(6) specifically for propane, or use a licensed gas contractor.
📊CSST Capacity Table — Gastite / TracPipe
BTU/hr · Natural gas · 0.5 in. WC pressure drop · Verify with manufacturer tables
CSST Size 20 ft 40 ft 60 ft 100 ft 150 ft
3/8″ CSST50,00035,00028,00022,00018,000
1/2″ CSST117,00081,00066,00051,00041,000
3/4″ CSST276,000192,000157,000121,00098,000
1″ CSST544,000379,000310,000239,000194,000
1-1/4″ CSST970,000676,000553,000427,000347,000
CSST Bonding Required: Florida adopted NFPA 54 2021 edition requiring CSST bonding per §7.13. All CSST must be bonded to the electrical grounding system with a direct bond at each section. Improperly bonded CSST failed in multiple FL lightning incidents. County inspectors check CSST bonding rigorously.
⚡Generator Gas Line Notes
Standby generators are the most common reason FL homeowners need gas line upsizing. Key planning considerations:
1
Dedicated line required
Generac, Kohler, and Briggs & Stratton require a dedicated gas supply line — not shared with other appliances on the same branch. The generator manufacturer's installation manual specifies minimum inlet pressure and pipe sizing.
2
Size for full-load BTU, not rated kW
A 22 kW Generac draws 250,000–260,000 BTU/hr at full load running on natural gas. At 50% load (typical residential), it draws about 155,000 BTU/hr. Size the gas line for full load per NFPA 54.
3
FL permit required
Generator gas hookup requires a mechanical/gas permit in all FL counties. The gas line must be inspected before the generator is commissioned. Licensed plumber or master gas contractor required. Typical cost: $250–$600 for permit + inspection.
4
Meter capacity check
Adding a generator often bumps total demand past the residential 175 CFH or 250 CFH meter capacity. Contact FPL/TECO/Peoples Gas to verify meter capacity before installation. Meter upgrade is utility-coordinated and may add 2–6 weeks to project timeline.
5
Propane vs. natural gas
In areas without natural gas service (much of rural FL), generators run on propane. Propane has 2.5× the BTU density of NG, so propane pipe can be one size smaller for the same CFH demand. Propane tank sizing: 120–500 gallon for residential standby. 250-gallon minimum recommended for 22 kW units.
🔧Gas Meter Sizing Guide
The gas meter must be sized to supply the total design demand. In Florida, the local distribution utility (FPL Gas / Peoples Gas, TECO Peoples Gas, or City Gas) owns and sizes the meter. This guide helps you understand what to request.
📊Residential Meter Sizing Chart — Natural Gas
Meter SizeMax CapacityMax BTU/hrTypical Use
B-175 (175 CFH)175 CFH178,500WH + range + dryer
B-250 (250 CFH)250 CFH255,000Adds small generator or pool heater
425 CFH Diaphragm425 CFH433,500WH + furnace + gen + pool
800 CFH800 CFH816,000Large residential / commercial
1,600 CFH1,600 CFH1,632,000Commercial / industrial
Utility coordinates meter size: You (or your licensed contractor) submit a load calc to the local utility showing total connected appliance BTU demand. The utility then determines if a meter upgrade is needed. Meter upgrades are typically free from the utility but require scheduling and may take 2–6 weeks.
🏛️FL County Permit Requirements — Gas Work
All gas piping work in Florida requires a mechanical/gas permit. Here are key requirements by major county:
Palm Beach County
Gas permit required. Licensed plumber or master gas contractor. CSST bonding strict. Hurricane strap required for exterior-mounted meters and generators. Call 561-233-5100.
Broward County
Permit via Broward County Building Division or city (Ft. Laud., Hollywood). 10-business-day review typical. CSST bond inspection at rough-in and final. 954-357-6350.
Miami-Dade County
Miami-Dade Building Dept. permit required. High Velocity Hurricane Zone (HVHZ) — extra fastening and CSST bonding. iBuild online portal. 786-315-2100.
Hillsborough County
Permit via Hillsborough County or Tampa (city). TECO Peoples Gas utility. CSST bonding and pressure test required. 813-272-5600.
Orange County
Permit via Orange County EPD or Orlando (city). Duke Energy / TECO gas service. Online permit portal at ocfl.net/Development. 407-836-5550.
Lee / Collier Counties
Lee County Building Dept. or Collier Growth Mgmt. TECO Peoples Gas. Post-Ian: all gas work requires full pressure test with 20-min hold at 3× operating pressure. 239-533-8329.
Duval / Jacksonville
Consolidated City of Jacksonville permit. JEA gas service. Generator gas lines must be on separate branch. City Gas Company of FL. 904-630-1100.
Pinellas County
Pinellas County Building Dept. or city (Clearwater, St. Pete). TECO Peoples Gas. Online permits at pinellascounty.org/build. 727-464-3888.
FPC §409.1: All gas piping installations must comply with NFPA 54 (National Fuel Gas Code) as adopted by Florida. Unlicensed gas work is a 2nd-degree misdemeanor. Only a licensed plumber (CFC, CPC), certified gas line contractor, or certified underground utility contractor may pull a gas permit in Florida.
📋Inspection Checklist — What Inspectors Check
§409.1
Pipe material: black steel, CSST, PE (underground), or copper (LP only)
Required
§409.2
Pressure test: 1.5× operating pressure, minimum 10 PSI for 15 minutes with no drop
Required
§409.3
CSST bonding: direct electrical bond to grounding electrode system, #6 AWG minimum
Required
NFPA 54 §7.8
Shutoff valve within 6 ft of each appliance, readily accessible, no threading required for CSST
Required
§409.5
Pipe support: black steel every 8 ft horizontal, CSST per manufacturer (every 4 ft typical)
Required
§409.6
Drip leg (sediment trap) at each appliance connection with quick-connect coupling
Required
§409.7
Pipe labeled or marked at intervals ≤10 ft in concealed locations
Required
NFPA 54 §6.1
Load calculation on permit application showing total BTU demand and pipe sizing per table
Required
FPC §106.1
Licensed contractor on permit — CFC, CPC, or gas line contractor license number
Required
🔥Get a Free Gas Line Sizing Quote
Whether you're adding a generator, tankless water heater, pool heater, or new appliances — our licensed gas contractors provide free on-site quotes. We handle permits, CSST bonding, pressure testing, and final inspection.
✓ Licensed & Insured: All gas work performed by Florida-licensed plumbers and gas contractors. Permits pulled, inspections scheduled, and CSST bonding completed to code.
💡Why Gas Line Sizing Matters in Florida
Florida's unique conditions make proper gas line sizing critical:
1
Generator surge is Florida's #1 gas line issue
Post-Irma and Ian, generator installations increased 400% in South Florida. The vast majority of undersized gas lines we see are homes that added a 22 kW generator to a 175 CFH meter that was already running a tankless water heater. The generator starves for gas.
2
Tankless water heaters demand 5× more gas than storage
A tankless WH demands 150,000–199,000 BTU/hr when firing. A storage water heater only needs 36,000–50,000 BTU/hr. Many FL homes upgraded to tankless without upsizing the gas line — the result is long wait times for hot water and pressure drops at other appliances.
3
Galvanized pipe corrodes in FL humidity
Galvanized steel gas pipe installed before 1985 is internally corroding in most FL homes due to humidity and moisture. Rust particles clog appliance valves and reduce pipe ID, effectively shrinking capacity. Full repipe to CSST or black steel recommended for homes over 30 years old.
4
CSST lightning strikes are a FL-specific risk
Florida is the lightning capital of the US. Improperly bonded CSST is vulnerable to lightning-induced arc-through — gas fires that start inside walls. Every FL CSST installation must be directly bonded per NFPA 54 §7.13 and FPC §409. Inspectors take this seriously after several FL incidents.
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