Bollards are excellent security devices that limit vehicle access to protect buildings, establish pedestrian and work zones, and reduce accidents. To work effectively, they must be built to accepted industry standards. Learn about typical bollard dimensions and spacing and why they matter.
Standard Bollard Dimensions
Safety regulations and your intended purpose will dictate the size, type, and installation method of bollards needed. However, industry standards keep most bollards within a limited range of sizes.
How Tall Should a Bollard Be?
Bollard height is usually between 30 and 48 inches, with most falling between 36 and 42 inches. A 42-inch bollard provides sufficient protection against many different impact scenarios.
Shorter bollards, below 36 inches, are frequently used to direct foot traffic. They are common in parks, at crosswalk entrances, and in other public spaces. For example, you might find 24-inch posts marking a traffic island. They are an excellent, cost-effective solution in situations with low impact risk.
Taller bollards, including those above 42 inches, are more visible and designed for high-risk areas. Consider adding tall bollards to loading docks and other areas with oversized vehicles and heavy equipment. In addition to being highly visible, they can more effectively stop vehicles with high ground clearance than shorter versions.
Standard bollard heights do not include any portions that are installed underground. While you can mount bollards to existing surfaces, those providing the highest level of protection have deep foundations that absorb impact.
Standard Bollard Diameters for High-Impact Protection
Standard bollard dimensions are generally between four and six inches. This dimension is often the same for both standard and heavy-duty bollards. However, size is not the only factor that affects performance. The dimensions relate to the bollard core, exclusive of any decorative sleeves.
The thinnest bollards are only a few inches across. These are excellent for marking pedestrian areas and guiding light traffic. They can also be used to designate specific sections in entertainment and sports venues.
The largest bollards can be 12 inches or wider. They are generally designed to restrict heavy traffic traveling at significant speeds. A crash test rating will provide more details about specific bollard capabilities.
Spacing Considerations for Standard Bollards
The spacing of bollards should effectively limit the intended types of traffic. This is usually less than five feet apart. The American Society for Testing and Materials, which performs crash testing and establishes ratings, recommends a spacing of no more than 48 inches for maximum effectiveness.
Spacing can extend further in properly designed bollard arrays. However, they should not be so close that it discourages correct use.
Another consideration behind standard bollard spacing is accessibility. The Americans with Disabilities Act requires at least three feet between bollards to allow wheelchair access.
When a single bollard is used to obscure an entrance, it should allow enough clearance on at least one side for accessibility, or an alternate ADA-accessible entrance should be available. For example, if a bollard is at the end of a pedestrian-only path to keep bicycles out, you will naturally also exclude wheelchair users and need to make accommodations.
Reasons Behind Bollard Dimensions
There are several reasons behind common bollard dimensions. First, they must be of sufficient size, depth, and spacing to perform the intended task. This applies to the diameter and construction method of bollards as well. For example, a 12-inch tall bollard is not likely to stop a truck as easily as one that is 42 inches high.
Building codes may require bollards to be within a specific size range. These vary by location, so be sure to check with your local building department for bollard code requirements before choosing a design.
Visibility is also a factor. You can see a larger bollard more easily than a small one. This is important in high-traffic areas where bollards are the only things protecting pedestrians or workers from vehicles.
Tips for Choosing the Right Size Bollards for Your Location
When selecting a vehicle access control solution like bollards, you should consider several factors that can affect effectiveness, installation, and placement. These include:
- Intended purpose of the bollards
- Presence of underground utilities or obstructions
- Size of area needing coverage
Crash rating is just as important as bollard size. A well-engineered design can provide effective protection in a small package. However, you may need to take extra steps for visibility.
Custom Bollard Dimensions To Meet Your Access Control Needs
Bollards reliably control vehicle access to restricted areas and direct pedestrian traffic. They are used in commercial, municipal, and residential areas. At Delta Scientific, we build bollards to meet rigorous performance and safety standards. Contact us to find bollard dimensions that meet your site’s unique safety needs.