Olympic Fire Table from Montana Fire PIts

Gas Line Sizing for Gas Fire Pits and Fire Features

Gas Line Sizing Chart for Fire Features and Supporting Videos to Get Your Project Installed

Quick answer: Measure the gas line from your meter or propane tank to the fire pit, add 5 feet for every fitting, then find that length and your pipe size in the chart below. The number is how many thousand BTUs per hour the line can deliver. Your burner’s BTU rating should be at or below it. Example: a 374,000 BTU natural gas burner on a 30 ft run needs a 1″ line.

Start Your Fire Pit Plan with Gas Line Sizing

How to size your gas line

  1. Know your burner’s BTU rating. It’s listed on every Crossfire burner.
  2. Measure the run. Distance in feet from the gas meter or propane tank to the fire pit.
  3. Add 5 ft per fitting. Every elbow, tee and connector restricts flow.
  4. Add other appliances. If a grill, furnace or water heater shares the line, add their BTUs to your burner’s.
  5. Read the chart. Find your length (round up), then pick the smallest pipe size whose number is at or above your total BTUs (in thousands).
  6. Check pressure. Propane: 11–13″ water column. Natural gas: 7–10″ water column. Too high = loud “blowtorch” flames; too low = weak flames.
  7. Have a licensed gas pro confirm and install. Pipe material, supply pressure and local code all affect the final size.

Good news: Crossfire burners still give great flames at about 70% of their rated fuel. A 180K BTU burner on a line that delivers 150K will look great.

How to Read the Gas Line Sizing Chart

Natural gas pipe sizing chart

Inlet pressure less than 2 psi · 0.5″ w.c. pressure drop · specific gravity 0.60. Values in thousands of BTU per hour (1 cubic foot of natural gas ≈ 1,000 BTU).

Natural gas: capacity by pipe size and length (thousands of BTU/hr)
Length (ft) ½″ ¾″ 1″ 1¼″ 1½″ 2″ 2½″ 3″ 4″
10 172 360 678 1,390 2,090 4,020 6,400 11,300 23,100
20 118 247 466 957 1,430 2,760 4,400 7,780 15,900
30 95 199 374 768 1,150 2,220 3,530 6,250 12,700
40 81 170 320 657 985 1,900 3,020 5,350 10,900
50 72 151 284 583 873 1,680 2,680 4,740 9,660
60 65 137 257 528 791 1,520 2,430 4,290 8,760
70 60 126 237 486 728 1,400 2,230 3,950 8,050
80 56 117 220 452 677 1,300 2,080 3,670 7,490
90 52 110 207 424 635 1,220 1,950 3,450 7,030
100 50 104 195 400 600 1,160 1,840 3,260 6,640
125 44 92 173 355 532 1,020 1,630 2,890 5,890
150 40 83 157 322 482 928 1,480 2,610 5,330
175 37 77 144 296 443 854 1,360 2,410 4,910
200 34 71 134 275 412 794 1,270 2,240 4,560
250 30 63 119 244 366 704 1,120 1,980 4,050
300 27 57 108 221 331 638 1,020 1,800 3,670
350 25 53 99 203 305 587 935 1,650 3,370
400 23 49 92 189 283 546 870 1,540 3,140

Propane (LP) pipe sizing chart

Low-pressure propane after regulation · 11″ w.c. inlet · 0.5″ w.c. pressure drop · specific gravity 1.50. Values in thousands of BTU per hour. Example: a 787,000 BTU burner on a 20 ft run needs a 1″ line.

Propane: capacity by pipe size and length (thousands of BTU/hr)
Length (ft) ½″ ¾″ 1″ 1¼″ 1½″ 2″ 2½″ 3″ 4″
10 291 608 1,150 2,350 3,520 6,790 10,800 19,100 39,000
20 200 418 787 1,620 2,420 4,660 7,430 13,100 26,800
30 160 336 632 1,300 1,940 3,750 5,970 10,600 21,500
40 137 287 541 1,110 1,660 3,210 5,110 9,030 18,400
50 122 255 480 985 1,480 2,840 4,530 8,000 16,300
60 110 231 434 892 1,340 2,570 4,100 7,250 14,800
80 101 212 400 821 1,230 2,370 3,770 6,670 13,600
100 94 197 372 763 1,140 2,200 3,510 6,210 12,700
125 89 185 349 716 1,070 2,070 3,290 5,820 11,900
150 84 175 330 677 1,010 1,950 3,110 5,500 11,200
175 74 155 292 600 899 1,730 2,760 4,880 9,950
200 67 140 265 543 814 1,570 2,500 4,420 9,010
250 62 129 243 500 749 1,440 2,300 4,060 8,290
300 58 120 227 465 697 1,340 2,140 3,780 7,710
350 51 107 201 412 618 1,190 1,900 3,350 6,840
400 46 97 182 373 560 1,080 1,720 3,040 6,190

Download the printable gas pipe sizing chart

Use these charts as a guideline only. They don’t account for pipe material (black iron vs. CSST), other appliances, meter pressure or fittings. Montana Fire Pits and Warming Trends are not licensed gas professionals. Consult a local gas professional to determine your actual BTU availability.

Parts for your gas line

Gas line sizing FAQ

  • What size gas line do I need for a fire pit?

    It depends on your burner’s BTUs and the length of the run. Most residential fire pits need a ¾″ or 1″ line. For example, on natural gas a 1″ line delivers about 374,000 BTU at 30 ft and 284,000 BTU at 50 ft.

  • Is a ½″ gas line big enough for a fire pit?

    Usually not. A ½″ natural gas line delivers only about 118,000 BTU at 20 ft and 72,000 BTU at 50 ft, which is less than most fire pit burners need.

  • How does distance affect gas line size?

    The longer the run, the less gas reaches the burner. A ¾″ natural gas line drops from 360,000 BTU at 10 ft to 151,000 BTU at 50 ft. Add 5 ft for every fitting when you measure.

  • What gas pressure does a fire pit need?

    Propane fire pits need 11–13 inches of water column. Natural gas fire pits need 7–10 inches of water column.

  • Will a burner work if my line can't supply its full BTUs?

    Crossfire burners perform well at around 70% of their rated BTUs. A 180K BTU burner on a line that delivers 150K BTU still makes great flames.

  • Can I install my own fire pit gas line?

    No. Fuel components must be connected by a licensed gas professional, such as a plumber, HVAC contractor or propane supplier, to make sure the line is safe and meets local code.