Playground Guide Part 7
Choosing a Playground Surface
Over 70% of all playground equipment injuries occur because of falls to inadequate or nonexistent surfacing. The surfacing is the first line of defense in helping prevent playground injuries. Playgrounds in the United States installed over hard surfaces such as asphalt, concrete, dirt, or even grass are not compliant resilient safety surfaces. In Canada, grass and dirt are compliant surfaces for none moving equipment that has a playing surface below 450 mm. However, play equipment over 450 mm requires a compliant resilient safety surface to be compliant. You can help reduce these injuries by providing resilient safety with a critical fall height greater or equal to the equipment’s highest accessible area.
Surfacing costs can vary dramatically and sometimes makeup 40 to 50 percent of your overall playground area’s budget. Where accessible routes are required, you could use poured in place rubber or rubber tiles and then use loose fill materials such as engineered wood fiber in other areas to save money. This way, combining surfacing materials is a great way to save money and still be compliant with CSA and ASTM fall heights, ADA, Annex H, and AODA (in Ontario) accessibility requirements.
There are two main categories of resilient safety surfacing in the market: unitary and loose fill.
Henderson Tip: Get your surfacing manufacturer or sales representative to at least provide you with a letter of compliance to ASTM F1292 and or ASTM F1951. Better yet, have your resilient surfacing tested by a third-party inspector to confirm your surfacing is compliant and continue to have it checked yearly.
Engineered Wood Fibre
Engineered wood fiber (EWF) is a premium loose fill material processed from new or virgin wood. Engineered wood fiber does not contain any twigs or leaves. Engineered wood fiber has excellent fall height properties. With a depth of 300 mm (11.81 in), a passing fall height of 3 m (118.11 in) or more can be obtained when conducting surface impact testing.
Engineered wood fiber has many advantages. It is easy to maintain. It is wheelchair accessible, free of contaminants, disperses and scatters less than other aggregates because it knits together. Engineered wood fiber tends to be more durable than plain wood chips and is less abrasive on your playground than sand and pea gravel. It also can help retard insect infestation and fungal growth.
Upfront costs for engineered wood fiber is more expensive than other natural aggregates. Like other loose fill, it can hide foreign objects. High humidity, moisture, and freezing reduce its resiliency. It can also decompose over time and may support microbial growth.
Wood chips are a loose fill material composed of small chunks of wood from trees and typically do not contain twigs and leaves. New wood chips look like freshly chopped up natural wood, not the garden mulch people are used to seeing. Wood chips should be free of CCA and other forms of chemical treatment. Wood chips should come from trees and not chipped up wooden pallets containing nails and other hazards. A passing fall height of 3 m (118.11 in) or more can be obtained with wood chips when doing surface impact testing on a 300 mm (11.81 in) depth.
Wood chips are aesthetically pleasing compared to sand. The cost is relatively low, but it depends on your location. The nice thing about wood chips is that it is easy to maintain. Wood chips can also retard insect infestation and fungal growth.
Disadvantages reside around the chips being thrown, displaced, and can hide foreign objects such as broken glass. Freezing temperatures mixed with high moisture and humidity can reduce the resiliency of wood chips.
Wood chips cost more to maintain because of scattering, cleaning up, removing foreign objects, and topping up every 1 to 3 years.
Sand is a loose fill aggregate composed of small particles of varying sizes. Depending on where you live, sand can be one of the most economical choices for resilient surfacing you can get. Sand can be an excellent non-compacting surface. However, sand has many different particle sizes and shapes and base rock compositions. Some types of sand are designed for compaction and are unsuitable for playground use. When dealing with your aggregate supplier, clearly specify that the sand is for a playground’s resilient surface.
Sand is easy to install; it is durable, nonflammable, and does not grow mold or microbes.
A significant disadvantage is that wheelchairs cannot traverse it. Children often pick it up and throw it, which gets into people’s eyes or mouth. Sand also tends to get into shoes and stick to your skin. It can hide animal droppings and other objects. Sand is abrasive and hard on your playground’s painted surfaces and can wear the paint off in high traffic areas. It tends to blow and scatter around and tracked into buildings on shoes, causing damage to floors. Most sands retain moisture and freeze solid in cold temperatures. Alternatively, sand gets hot from direct exposure to the sun in warm temperatures.
Due to scattering, displacement, top-ups, and its tendency to hide foreign objects, sand costs more to maintain than unitary materials such as rubber. Depending on your site conditions, sand may require topping up to replace lost sand every 1 to 3 years.
Pea gravel is a loose fill aggregate that is available in most locations. Pea gravel is a small stone that has a smooth rounded shape, hence the name pea stone. (see image below). A passing fall height of 2.5 m (98.43 in) can be obtained when doing surface impact testing on a 300 mm (11.81 in) depth.
The advantages of pea stone are like sand. This material has the added advantage of providing better drainage and is less attractive for animals as a dumping ground.
Pea stone can be easily dispersed, thrown, and can create a tripping hazard on hard surfaces such as asphalt and concrete. It can also get lodged in noses and ears with younger children, and sometimes young children swallowed it. Like sand and other loose fill materials, pea stone can hide foreign objects. Wheelchairs cannot traverse this material either. Pea gravel is particularly susceptible to the formation of “hardpan.” Hardpan is a condition where the material becomes very hard just below the surface’s top due to contamination. Freezing temperatures, coupled with high moisture and humidity, can reduce the resiliency of pea gravel. Pea stone tends to heat up in the direct sun.
Like sand, pea gravel has a higher associated maintenance and inspection cost. This material tends to scatter and must be topped up every 1 to 2 years to maintain your surfacing resiliency. You will also need to inspect the material for foreign objects and check for “hard panning,” which needs to be broken up using a rototiller. You will often have to clean surrounding areas such as sidewalks and asphalt because the pea gravel tends to scatter.
Shredded rubber is a loose-fill material with an excellent environmental and recycling component—created from shredding rubber tires into small pieces. For playground use, shredded rubber has all the metal and wire removed. Have your shredded rubber supplier confirm that the rubber is free from lead, toxins, latex, or anything else that may be harmful to children. A passing fall height of 3 m (118.11 in) or more can be obtained when doing surface impact testing on 200 mm (7.87 in) depth.
Shredded rubber is easy to install, very durable, not abrasive on your playground paint job, and does not support microbial growth. Animals are not attracted to it.
Like other aggregates, shredded rubber can hide foreign objects. It can be thrown, tends to get scattered and displaced, and requires more maintenance, can be ingested and or lodged in the ears or nose. Quality can vary a lot depending on the type of tire used, is it new tire rejects or old tires. Winter tires are softer than summer tires or truck tires. Like all aggregates, shredded rubber requires regular maintenance and inspection to remove foreign materials and requires topping up every 2 to 5 years.
Rubber tiles are factory-engineered unitary surfaces commonly sold in preformed interlocking tiles. They are composed of rubber aggregate and a chemical binder and formed in a press. Because of the controlled manufacturing environment, rubber tiles can provide a guaranteed passing fall height value. As with pour-in-place surfacing, rubber tiles require little maintenance. They are available in many different colors and thicknesses. Depending on the manufacturer, a passing fall height of 3 m (118.11 in) can be obtained when doing surface impact testing on 200 mm (7.87 in) depth. Note that maximum passing fall height, impact attenuation, longevity, and warranty vary from one manufacturer to another.
Rubber tiles are fully wheelchair accessible and have consistent impact attenuation. Rubber tiles are easy to clean and maintain, which reduces maintenance costs over the long term. Because they are factory-manufactured with consistency and uniformity, rubber tiles tend to degrade less than pour-in-place surfaces.
Disadvantages of rubber tiles, like all synthetic surfaces, are more expensive than natural aggregates. They may not last the full life cycle of your new playground and may require replacement, so your playground surfacing remains safe. As noted above, maximum passing fall height, impact attenuation, longevity, and warranty vary from one manufacturer to another.
Although maintenance is less than for loose fill materials, rubber tiles still require regular inspection for foreign objects and damage to the tiles. Look for sections that may come loose or tears in the rubber tiles. You should maintain your rubber tiles by sweeping, vacuuming, or blowing them clean regularly. The great thing about rubber tiles vs. pour-in-place rubber surfacing is that the tiles are easily replaceable when required due to wear, damage, or loss of impact properties. Remember that the new repair may not match your existing surface’s color like any synthetic surface because color fading occurs over time.
Pour-in-place rubber surfaces
When you purchase a pour-in-place resilient surfacing, you are getting a seamless synthetic unitary surface. Most products use a chemical binder with a rubber granule filler that is mixed and placed on-site. Some newer products on the market use chemically bonded spherical polyurethane pebbles as a topcoat and use a combination of foam and recycled rubber to achieve the cushioning. The pour-in-place resilient surfacing is often installed over concrete or asphalt. Still, it can also be installed over a compacted granular base. A passing fall height of 3 m (118.11 in) can be obtained when doing surface impact testing on 200 mm (7.87 in) depth with some products. Note that maximum passing fall height, impact attenuation, longevity, and warranty vary from one manufacturer to another.
One of the best advantages of pour-in-place rubber surfacing is wheelchair accessibility for persons with mobility disabilities. Other than rubber tiles, no protective surface can compare with the wheelchair accessibility of pour-in-place rubber surfacing.
Pour-in-place rubber surfacing does not scatter or disperse, so no topping up is required. It is also straightforward to clean. Pour-in-place surfacing also has consistent impact attenuation compared to surfaces that disperse and change depth resulting in reduced impact attenuation. Pour-in-place surfacing is easy to clean and cannot hide foreign materials. It is much easier to maintain, thus saving costs in the long term. Pour-in-place surfacing is more stable than organic aggregates, which deteriorate over time. This firm and stable surfacing as no abrasive effect on play equipment paint finishes and deck surfaces, unlike sand and pea gravel. Playgrounds with pour-in-place surfacing often appear cleaner and in better shape than aggregate surfacing.
Pour-in-place surfacing is available in a wide variety of colors, and graphics, shapes, and designs that create an aesthetically pleasing surface. As noted above, quality, durability, impact attenuation, and warranty vary from one manufacturer to another.
Disadvantages of pour-in-place rubber surfacing are cost (up to 50% or more of the playground’s total cost) and a shorter lifespan than the playground equipment. In time, impact attenuation declines over the life of the surfacing due to sunlight ultraviolet ray exposure.
Although easier to maintain than loose fill surfaces, you should clean it regularly by sweeping, blowing, or vacuuming it. Cleaning helps prevent dust and other small particles impending on the surface, reducing the surface’s impact attenuation. Check for damaged section, typically happens at the edges or under high wear areas like under swing seats, end of slides, or around spinning equipment.
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