by Tony Thornton President, Thornton Fence Consulting Group
Post Setting Fence Standards The ASTM Standards Committee: what is this? The committee’s responsibility is to review and develop material standards that meet the demands of the fence industry. The goal is to find common language to define fence and gate systems while maintaining safety requirements and security demands. The F14 committee has several subcommittees as well. Subcommittee F14.10 focuses on specific applications and other fence systems and components for wood fence and other nonmetallic/nonspecific components and fence products within special applications such as tennis courts, ball fields, swimming pools, temporary fence, etc. Subcommittee F14.15 is a new subcommittee focusing on Gates and Gate Hardware formed to oversee the review and development of guides and standards for all aspects of gate systems across the different materials used for fence. Subcommittee F14.30 focuses on Rigid Polymer Fence Systems. Subcommittee F14.40 focuses on Chain Link and Wire Accessories. Subcommittee F14.50 focuses on High Security Fence and Perimeter Barriers. ASTM International is a globally recognized leader in the development and delivery of voluntary consensus standards. Today, over 12,000 ASTM standards are used around the world to improve product quality, enhance health and safety, strengthen market access, and trade, and build consumer confidence. The above statement is the who and what is ASTM, so how does this affect the fence industry? The ASTM Standards for Fence Materials
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and Products, 14th Edition is the backbone of what the fence industry is required to understand and provide at a minimum. These standards provide protection to the consumers that a professional fence installer has met or exceeded the products and installation standards that are outlined for the fence industry. As an industry we must adopt these standards and promote that your company installation meets or exceed the ASTM Fence Standards. We are trade professionals and as professionals we must hold ourselves and others to a higher standard and making the ASTM Fence Standards a priority, we will elevate our industry to the professional level we all strive for. A common discussion within the industry is Fence Post Setting Requirements, regarding post depth, diameter of hole required and frost line issues. The following is a quick reference for the professional fence contractor. Fence posts must be placed at the correct depth depending on the type of fence, how it will be used, the terrain and the soil type of the site. ASTM International has created specifications for post hole diameter and depth that correspond with each fence type (see below). Note: If the dimensions for diameter and depth are provided by the project specifications, these will supersede ASTM specifications. Wood Fence - ASTM Designation: F537-01 • Diameter - at least 4” larger than largest dimension/diameter of post • Depth - one-half the finished height of the
fence minus 6”, maximum 48” • Concrete collar footing with 4” larger diameter at base than at top of post hole for frost/expansion • Footings should extend at least 6” below frost line or bell bottom of hole Metal/Ornamental Fence - ASTM Designation: F537-01 • Diameter – three times the largest dimension/diameter of post with concrete support • Depth - one-half the finished height of the fence minus 6”, maximum 48” • Concrete collar footing with 4” larger diameter at base than at top of post hole for frost/expansion • Footings should extend at least 6” below frost line or bell bottom of hole Vinyl/PVC Fence - ASTM Designation: F-1999 – 00 • Diameter - at least 4” greater than largest cross section of the post • Depth – a minimum of 24” plus 3” for each 1’ increase in fence height over 4’ • Footings should extend at least 6” below frost line or bell bottom of hole Chain Link Fence - ASTM Designation: F567-07 • Diameter - Four times the post diameter for post 4” and under, and 3 times the post diameter for larger posts • Depth – minimum of 24” plus 3” for each 1’ of fence height over 4’ • Footings should extend at least 6” below frost line or bell bottom of hole
