Five Things You Should Know About Fall Protection Standards Playground safety surfacing is governed by a standard called ASTM F1292. The technical name for the document is the Standard specification for impact attenuation of surfacing materials within the use zone of playground equipment. The ASTM F1292 Standard was designed to ensure that all materials used as playground safety surfacing meet a minimum level of fall protection. The standard contains information regarding minimum levels of safety performance as well as methods of testing potential surfacing materials both in a laboratory setting as well as at the playground after installation. The standard itself is a 23 page highly technical document and even a careful read can prove to be too technical to provide meaningful information to the average reader. In spite of its technical nature it is an extremely important and relevant document for anyone considering the purchase of playground safety surfacing. For this reason here are 5 things that you should know about the standard before evaluating playground surfacing materials.
1. The standard is based on scientifically proven methods for testing safety performance. In order determine whether or not a surfacing material is acceptable for use as playground safety surfacing, each surface must be tested according to the guidelines set forth in the standard. Interestingly, the entire body of research relating to impact force and head trauma began with the U.S. military. Initially the military wanted to know how much G force a pilot could withstand in the event they had to eject from a fighter plane. Research in this area continued to develop within the aviation industry and eventually the automotive industry as the market began to demand safer vehicles. The methodologies and instruments used to test playground surfacing were borrowed from the aviation and automotive industries. Each potential surfacing material is tested with a “crash test dummy like� instrument which sends critical information about the impact to a hand held computer. The key measurements used to determine safety performance are referred to as Gmax (g-force) and HIC or Head Injury Criteria. Both of these values relate to the ability of the surface to reduce the force of impact, cushion falls and reduce serious head trauma.
2. The standard is designed to prevent life threatening and debilitating head injuries only. Many people believe that as long as a playground surface complies with the ASTM F1292 standard, children will be safe in the event of a fall to the surface. Not only is this inaccurate, it represents a potentially dangerous misconception. The maximum impact thresholds set forth in the standard are designed to prevent only the most severe forms of debilitating head trauma. The Gmax and HIC values used to determine the safety performance a of playground surface are based on the relationship between impact force and head trauma. The ASTM Standard establishes maximum thresholds of 200 Gmax and 1000 HIC for all playground safety surfacing materials. In other words all surfacing materials must produce values under 1000 HIC and 200 Gmax to be considered compliant. The key concept here is that these values are the maximum threshold which must never be exceeded at any time over the entire life cycle of the product.
3. The standard Illustrates the relationship between HIC and Gmax levels and the likelihood of various type of injuries.
PROBABILITY OF INJURY
The following graph can be found within the technical standard. When interpreting the graph, note that the bottom of the chart shows a HIC range from 0 to 3000 HIC. The right side of the chart shows the likelihood of injury in percentage points, and the graph lines outline the various types of injury as described in the legend on the right.
NO INJURY
100% 80%
MINOR INJURY
A skull trauma without loss of consciousness, fracture of nose or teeth, superficial face injuries.
MODERATE INJURY
Skull trauma with or without dislocated skull fracture and brief loss of consciousness. Fracture of facial bones without dislocation, deep wounds.
60% 40% 20% 0% 0
500 1000 1500 2000 2500 3000 HIC (Head Injury Criteria)
Cerebral contusion, loss of consciousness for more than 12 hours with intracranial CRITICAL HEAD INJURY hemorrhaging and other neurological signs; recovery uncertain.
FATAL
In the graph above you will note that the 1000 HIC requirement set forth in the standard is the point at which a critical head injury begins to depart from zero, and the likelihood of a minor injury is about 95%. When interpreting the above graph it may be helpful to understand the definitions of the various types of injuries shown in the legend on the right, and as defined within the standard.
4. The standard allows for stricter guidelines. The 1292 standard recognizes that the safety values set forth within it are the maximum allowable limits and are also limits designed around the prevention of serious head trauma only. Paragraphs within the standard also recognize that the ability of any surfacing system to cushion falls and reduce injury will diminish over the systems life cycle due to regular wear and tear, aging, UV exposure, temperature fluctuations and other factors. For this reason the standard acknowledges that the user of the surface may well wish to specify a level of safety performance that is better than the maximum thresholds set forth within the document. This is often done in order to reduce the likelihood of serious injury and to ensure that the surface remains under the maximum thresholds for the entire life cycle of the surface. A surface that performs close to the maximum thresholds at the time of purchase may well be non-compliant within a season or two of use. When evaluating playground surface materials it is wise to look for products that that provide the lowest possible HIC ratings that are achievable within your budget.
5. The standard allows for testing in the field. Most users evaluate the safety performance of a surfacing material based primarily on the test documents provided by the manufacturer before purchase. The test documents provided from the manufacturer should be certified documents from a third party accredited laboratory. Although this is an important part of the evaluation process, the 1292 standard recognizes that surfacing materials installed under a playground can perform significantly different than the material that was tested in the laboratory. One contributor to the difference may be the age of the original test document. Many other factors that are unique to each individual site, geographic region or installer for instance, can affect the final outcome of the installed product and therefore affect the safety performance. In light of this, the ASTM F1292 standard makes provisions and sets forth guidelines for testing of surfacing materials after they have been installed. The primary function of a playground surface is the provision of long term fall protection and the purchase of a synthetic playground surface can represent a significant investment. In light of this, many owners want to be assured that the actual surface installed in their playground complies with the HIC and Gmax values that they have specified within their purchasing contract. As a result many owners and specifiers are requiring a post installation field test of the surface as a mandatory deliverable within the contract. Did you find this article useful? If so you may want to read our article titled 5 things to include in a performance based specification.