What is a Flange Extension and why would you need one?
A flange extension is the name we give to a fitting that allows the flange to be extended further away from the valve. This becomes advantageous for those who wish to use thicker walls, stones, or blocks for their fire pit enclosure as you're then able mount the flange on the outside of your enclosure while the valve remains inside.
How to Use It:
A Standard Shut Off Valve & Flange
So the idea of a flange extension is simple: the shut off valve features a gas inlet¹ a gas outlet², and a 3/4" male fitting³ where the flange usually threads onto.
A Flange Extension
Instead of threading the flange directly onto the valve, we're going to use a flange extension to extend this "fitting" out farther from the valve. The Flange Extension¹ itself is just a 3/4" threaded pipe fitting so we'll attach the flange extension to the shut off valve with a common 3/4" coupler² and then the flange³ will thread onto the other end of the extension.
The Extension Installed in a Paver Stone
We've chosen to make our flange extensions 6" long to account for the most commonly sized paver stones (between 7"-8") so that when paired with the length of the shut off valve's fitting, the coupler, and the flange fitting, we reach the desired length. In this particular application, we cored a 1 3/8" hole through to accommodate the diameter of the fittings.
Custom Sizing an Extension
Keep in mind, when it comes to flange extensions – the shut off valve fitting¹ and the flange fittings² do not need to be tightened since they will not carry gas - they only need to be tight enough to fit, so you'll have some "wiggle" room to play with the length of your extension. If your enclosure walls are longer, shorter, or just an odd size - remember, you can use multiple flange extensions or cut your extension to the exact size you need.
Longer Keys for an Extended Flange
Finally, when the flange extension is installed, all you'll need is a key that's long enough to reach the valve and you're all set.
Flange extensions are a commonly needed component to finish your DIY gas fire pit in order to extend the flange from the shut off valve itself. This affords you the ability to use your own choice in custom stone, brick, or enclosure walls and keep the same functionality.