Most people ask “how many BTUs do I need?” and expect a simple number. The honest answer is: it depends almost entirely on what your gas line can actually deliver. Pick a burner that outpaces your supply and you’ll get a weak, inconsistent flame no matter what the spec sheet says. Get the supply right first, and the BTU question largely answers itself.

This is one of the most common conversations we have with customers ordering a custom fire table. Here’s what actually matters — and none of it applies to propane, which is a separate discussion entirely.

BTU Is a Measure of Output, Not Performance

BTU (British Thermal Unit) tells you how much heat a burner can produce per hour when it’s getting the fuel it needs. A 96,000 BTU burner consuming the right volume of natural gas at the right pressure will perform as rated. That same burner starved of gas will underperform — not because the burner is wrong, but because the supply can’t keep up.

So while BTU output matters for heat and flame, it’s only half the equation. The other half is what your gas system can actually push through to the burner.

Your Gas Line Is the Starting Point

Two variables define what your natural gas system can deliver to a fire table: pipe diameter and run length from the meter.

Common residential gas line diameters and what to expect from each:

½-inch line — This is a small line, typically sized for a modest grill or a single small appliance. It can run a fire table, but it limits your options. With a 30-foot run to a high-performance burner, you can expect a flame in the 10–12 inch range. Functional, but not dramatic.

¾-inch line — The more common residential choice for outdoor fire features. With a comparable 30-foot run, the increased volume makes a significant difference — you can expect flames well over 20 inches from the same burner system. This is usually the minimum we recommend for anyone who wants a full, impressive flame.

1-inch line — This is for someone planning a high-output fire feature or who wants to future-proof the system for additional gas appliances down the line. It allows for maximum volume and is the right call for our larger burner configurations.

Run length matters just as much as pipe diameter. Gas loses pressure as it travels through pipe — the longer the run, the more pressure drop you experience by the time it reaches the burner. Add in fittings and valves, which each add equivalent footage to the calculation, and a long run can significantly reduce effective capacity even through a large pipe.

Dedicate the Line

One of the most important things you can do for a natural gas fire table is run a dedicated line — meaning nothing else is drawing from it. Most home appliances (furnaces, water heaters, stoves) are engineered to operate at low delivery pressure, typically around 3.5 inches of water column, which is roughly a quarter pound of pressure. Sharing a line means competing with those appliances for volume, and the fire table will almost always lose that competition when other things are running simultaneously.

A dedicated line, ideally fed directly from the meter with nothing else tapping into it, lets you maximize what you’re delivering to the burner.

Pressure: What Water Column Inches Mean

Gas pressure in residential systems is measured in inches of water column (WC). Standard residential natural gas service delivers around 7 inches WC — that’s approximately a quarter pound of pressure (0.25 PSI). Most home appliances are sized to run well within that range.

For a fire table, especially a high-output one, you want to know what’s available at the stub — the point where the outdoor gas line terminates and your fire feature connects. Ideally, you’re seeing at least half a pound of pressure (roughly 14 inches WC) available at that point. Your licensed plumber or pipe fitter can take that reading and tell you exactly what you’re working with before any burner is specified.

CastinCrete’s Burner Options

Our fire tables are built to order, and the burner is specified based on what your gas system can support. Standard configurations start at 96,000 BTUs — a solid, clean-burning output that works with nearly any standard residential gas supply — and scale up to 147,000 and 300,000 BTUs for fuller, more dramatic flame where the supply supports it.

For custom builds, there is no hard ceiling. The largest fire feature we have ever installed ran 1.3 million BTUs, combining two 680,000 BTU custom jet burners running off a residential gas supply — and produced flames reaching 24 inches. That is an extreme example, but it illustrates the range of what is possible when the gas supply and the burner are sized together from the start. If you want something outside the standard range, we can build it.

We also have access to a patented jet burner system — a high-performance burner design that pushes significantly more out of a given gas supply than a standard 304 stainless steel burner. The flame height numbers referenced above (10–12 inches from a ½-inch line, 20+ inches from a ¾-inch line) are based on this system. Standard burner configurations will perform differently — this system is not the norm in the industry, which is part of why the results are noticeably different.

A note on ignition: The burner is only part of the equation. Electronic ignition, manual ignition, and remote-controlled systems each have different requirements — and on high-output or custom builds, spark strength, valve timing, and wind resistance all become part of the specification conversation. When you are sizing a custom fire feature, ignition should be on the list from the beginning.

Don’t Oversize the Burner

The worst outcome is oversizing a burner relative to your supply. A 300,000 BTU burner running at 40% capacity because the gas can’t keep up doesn’t give you a bigger flame — it gives you an uneven, starved flame that doesn’t perform the way it should. Matching the burner to what your system can actually deliver is what gets you the result you’re looking for.

This is why we ask about the gas line before we spec a burner. It’s not a gatekeeping question — it’s the only way to make sure the fire table we build for you performs the way it should when you turn it on.

The Best First Step: Have Your Plumber Check the Stub

Before you finalize an order for a custom natural gas fire table, have a licensed plumber or pipe fitter look at what you have at the gas stub. Ask them to give you a reading — either in water column inches or PSI — so you know exactly what pressure and volume you’re working with. That one step tells us everything we need to size your burner correctly.

If you’re building new or planning a patio renovation, it’s worth having that conversation with your contractor before the concrete is poured. Running a 1-inch dedicated line during construction is a fraction of the cost of trenching and running it afterward.

Questions about what burner makes sense for your setup? Give us a call at (262) 501-9966, book a showroom visit, or stop by the showroom in Hartland. We’ll walk through it with you before anything gets ordered.