Fences, as described by the LP-Gas Code, are required to be an enclosure "with a minimum 6-ft high industrial-type fence, chain link fence, or equivalent protection.”  (NFPA 58 section 6.21.4.2, 2024 edition)

Since this requirement left many questions unanswered, this subject was brought up at a meeting of the NFPA committee that has the responsibility for writing the LP-Gas Code. First, the committee agreed that a lightweight fence that is easy to climb over or to knock down is not acceptable.  A fence held up by wooden posts or lightweight metal posts is not acceptable.  The fencing material commonly known as hog wire, chicken wire, or animal control fence is not acceptable, though some has been advertised as "industrial".  This is the lightweight material that may have smaller holes near the bottom than at the top.  And lightweight chain-link material commonly used at residential sites does not meet the requirement of being industrial-type.

It was also agreed that industrial-type fence material that is at least five feet tall and properly supported can meet the six-foot requirement by stringing at least a few rows of barbed wire along the top, taking it to six feet high.

The code specifies industrial-type fence, chain-link fence, or equivalent protection. Most fabric, not privacy, mesh type fabric, that is specified as industrial should be acceptable unless it is somewhat easy to climb. Some mesh fabrics can be specified with "apertures" as wide as twelve inches. If it is industrial weight and properly supported, that kind of fabric can be fairly easy to climb. Even the smallest apertures of three inches would not be hard to get a toehold to climb. Industrial-weight chain-link fabric clearly has the edge in providing security.

There was a statement made by the Standards Division in the late 1980s that wooden posts would be acceptable as long as they are solid and fully support the fence fabric. Experience since then has shown that wooden posts are not as stable for the long term as earlier hoped. We determined that industrial weight metal posts set in concrete are the appropriate method to use to support fencing fabric. However, based on the earlier position, we will allow existing wooden posts to remain in service as long as they are solid and stable. When it is time to replace them, they must be replaced by industrial-type metal posts.