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With the ever-growing popularity of Lava Stones, Fire Rocks, and Fire Balls being used in Fire Pits, and in particular the larger sizes, I was recently reminded whilst helping a client with an installation problem, how important it is how to use fire pit rocks correctly into your fire pit or fireplace.
How a Fire Pit Burner Works
To understand how to use Fire Pit Rocks and Fire Pit Stones and Lava Rocks it is important to understand the fundamental workings of a fire pit burner.
It is a common and understandable misconception that a fire pit burner works in the same manner as a domestic gas hob burner, but in fact, that is not the case.
The flame on an ordinary gas hob burner burns adjacent to where the gas exits, as shown in the image below.
However, a fire pit burner does not function this way. A Gas Delivery System might be more of an accurate description because it is designed to deliver the gas, which then percolates upwards through the fire media and ignites once at the surface.
The important point here is that the flame does not burn adjacent to the burner, but rather a couple of inches above it.
Despite most fire pit burners being manufactured using high-quality stainless steel, having the flame ignite close to the burner can cause substantial damage! A ‘protective’ layer is needed between the burner and the flame, allowing the gas to pass through.
As the gas percolates up through the fire pit media it also spreads out creating a more natural-looking fire pit flame.
How to Use Fire Pit Rocks
Larger-sized Fire Pit Rocks or Fire Stones require a base of smaller-sized lava rock to provide the protective layer for the fire pit burner ring. It will also help prevent the larger rocks from blocking the burner’s gas holes and maintain a more uniform, better-looking flame!
Hot spots due to insufficient or incorrectly installed fire media may cause your burner to warp due to the excessive heat, or worse, irreparable damage, rendering your burner unfit for purpose.
The objective here is to bury the burner under this small-sized lava rock filler until there is at least 1/2″ over the burner. Please note that following the recommendation of the manufacturer for this is important.
It is interesting to note that two of the leading manufacturers of burners in the US have slightly different recommendations on this matter. One recommends the 1/2″ we have already mentioned the other says to fill only to be level with the top of their burner.
The gas fire pit lava rock filler concept applies to both Natural Gas and Propane installation, however, they may have differing manufacturer depth recommendations.
The same principle can also be used for fire glass, especially the larger-sized variety.
Having installed your filler base you can then arrange your larger Lava Rocks or Stones on top.
American Fireglass has a great range of Fire Rocks and Fire Balls, however, they advise that the larger rocks and fire stones must not be installed without a smaller-sized lava rock base.
Tips when Installing the Fire Rocks
Ensure your fire glass or lava rock does not prevent a Spark Ignition Probe from functioning. Some Spark Ignition Fire Pit Kits include a protective cage, but many don’t so you need to ensure that nothing is getting between the spark ignitor probes preventing a spark.
Too much lava rock in a Propane Fire Pit may make it difficult for the gas to rise to the surface due to propane being heavier than air. If you are unhappy with the flame check the depth level of the fire media over the burner, removing some may improve the flame quality.