A New World Standard for Amusement Rides
by T. Harold Hudson
ASTM Committee F24 is marking its 25th year of standards development for the amusement industry. F24 standards are recognized around the world and are the only U.S. standards specifically for amusement rides. Formed in 1978, this committee takes its work very seriously, for in the United States alone there are more than 300 million visitors to amusement parks and attractions each year and each one goes on multiple rides. It is estimated that visitors to U.S. parks and attractions get on and off an amusement ride almost 3 billion times each year. The industry has an amazing safety record (1) and F24s goal for 25 years has been to provide a framework of standards and guides that supports and improves this record.
F24s silver anniversary also coincides with the publication of a new World Standard for amusement ride design. F 2291, Standard Practice for Design of Amusement Rides and Devices, was passed earlier this year and is the most comprehensive standard developed to date. Taking its place on an imposing list of F24 standards for amusement rides, this standard took five years to develop and is the result of the collaborative effort of amusement ride experts and interested parties from around the world.
A Melting Pot
The committee is made up of almost 400 members including manufacturers (20 percent), operators (35 percent) and general interest (45 percent). Members include regulators, inspectors, engineers, technicians, designers, owner/operators and interested parties. These professionals come from Australia, Bahrain, Brazil, Canada, France, Germany, India, Italy, Japan, the Netherlands, Russia, Switzerland, the United Kingdom, and the United States. Many serve on similar standards committees in their countries. This melting pot of experienced experts generates consensus safety standards that provide a road map for a dynamic, high-tech industry that has fun, excitement and entertainment as its mission.
A melting pot technical committee exists because amusement parks, of some form, can be found all over the world and there is international solidarity of interest in amusement rides and devices and their design, operation and safety. Furthermore, the community of amusement ride designers and manufacturers is relatively small; rides in most countries are similar in nature and in many cases may be from the same manufacturer. Standardization and formalization of best-practice technical provisions is in the best interest of manufacturers, owners and users alike, and F24 has addressed this need.
Also included in the melting pot are active participants and voting members from a dozen state agencies, including more than 20 state regulators, inspectors and consultants. Consequently, the committee is diversified in many ways and F24 standards are the beneficiaries.
In the committees 25-year history, 14 separate standards for amusement rides and devices have been developed. These standards address design, operations, maintenance, quality control, measurements, testing and terminology. As with most standards in the United States, ASTM F24 standards become mandatory when cited in a contractual agreement or when referenced and mandated by a governmental body. Presently 42 of the 50 states, virtually all states that have permanent amusement rides, have state regulations governing amusement rides. Many of these states incorporate all or part of the F24 standards in their regulations, making them law in that state. In addition, the amusement industry associations, the International Association of Amusement Parks and Attractions, the Outdoor Amusement Business Association and the Amusement Industry Manufacturers and Suppliers International have supported F24s efforts since its inception and recommends that its members support and utilize the standards. Most buyers (owners and operators) in and many buyers outside the United States cite ASTM standards in their purchase contracts and utilize them at their facilities.
The World Standard
F24 does not refer to F 2291 as the World Standard as hyperbole. We use this appellation because one of our overall goals was to encompass the common elements of existing and in-development standards around the world as well as U.S. (ASTM) philosophy and requirements in a new and comprehensive design standard.
The development of the World Standard was a deliberate but natural step for the committee. The process began with a special task group, which was formed to review existing World Standards, perform a needs assessment and develop a plan of work. The special task group consisted of approximately 25 members of F24, some focusing on the entire standard and some only on specific issues or a few sections within the new standard. The international flavor of F24 permeated the task group and members from several countries participated in most work sessions. These members brought their experience and expertise to the table, but more importantly, they brought different perspectives that helped make the standard technically complete as well as straightforward and succinct.
The needs assessment showed that, while the existing performance-based standard, F 1159, Practice for the Design and Manufacture of Amusement Rides and Devices, was adequate for some amusement rides, it did not address the detailed design criteria needed for todays high-tech rides and in todays environment. In other words, a detailed design standard was warranted in addition to the existing performance based standard.
While F 2291 was under development, the European Committee for Standardization (CEN), under the leadership of Germany, Italy and the United Kingdom, were working on a comprehensive design standard (European Norm) for Fairground and Amusement Park Machinery and Structural Safety (prEN13814). This new standard, along with standards for other areas of public safety, is destined to become the law of the land in Europe, but at the moment is yet to be approved. Throughout the F 2291 development process, European Union standards committee representatives participated in the F24 effort and F24 representatives monitored progress on prEN13814.
F24 also reviewed other existing standards and enlisted the assistance of knowledgeable world experts both in and outside the committee. The major goals were to a) generate the most comprehensive and best possible amusement ride design standard for the United States, b) consider requirements in other recognized standards, and c) minimize development time. The aim was to satisfy U.S. needs but, where possible, be in harmony, rather than in conflict, with other recognized standards around the world, including the European Norm.
In order to expedite the work, sub-task groups were formed to address logical sub-elements of the standard on an isolated and individual basis. Many elements of the standard could then be developed in parallel, thereby reducing the overall development time. The World Standard has 15 sections, which were developed by five distinct groups with a leader and volunteer experts in each group. The work of the sub-task groups was reviewed by the World Standard Task Group, combined and assembled into logical order, and reviewed by F24 prior to balloting. This was an ardent iterative process but took maximum advantage of the experience and expertise of the F24 cast of experts.
The World Standard Task Group and sub-task groups met on an as needed basis face-to-face, by telephone conferencing, and through the ASTM Internet-Based Standards Development Forum. Face-to-face work sessions were generally held quarterly in order to adequately analyze research data, review recommendations and draft language. The task group recognized that amusement rides and devices have unique requirements due to their special intent and purpose and they are also designed in accordance with common engineering laws and practice. Each of the five sub-task groups organized, reviewed and assembled pertinent engineering and technical standards and requirements in a manner that formed a comprehensive and unique standard for amusement rides. Throughout the development process a major effort was made to utilize existing, time-proven standards. As a result, F 2291 references over 60 codes, standards, guides, specifications, handbooks and charts.
F 2291 is unique because it details specific design criteria for amusement rides and devices, but one of the most unique elements of the standard is the inclusion of acceleration, or g-force, limits as Section 7 of the standard.(2) This is the first international standard to define limits for dynamic forces on amusement rides. The specified limits include magnitude and duration of g-force in the X, Y and Z planes as well as combinations of forces in these planes. Sixteen graphs and charts outline the g-force limits along with special conditions required to safely accommodate the force. In a related section and as part of the overall design criteria, the standard also describes minimum requirements for the patron compartment, restraints and safety clearance envelops, all important elements in relation to dynamic forces.
The development of g-force limits first took root in 1987 when a special task group in F24 drafted a standard focusing on acceleration limits. After much review and discussion, the committee decided that a standard that established acceleration limits on amusement rides would not be very useful unless there was a standardized methodology for measuring acceleration. This would provide a framework for analyzing forces, which would not only allow experts to speak the same language but more importantly, allow detailed comparisons of year-to-year and ride-to-ride acceleration data.
Therefore, this first effort to set acceleration limits some 15 years ago did not result in a g-force standard but resulted in the development of the worlds first and only testing standard for g-forces. ASTM F 2137, Practice for Measuring the Dynamic Characteristics of Amusement Rides and Devices, was approved and published in 2001.
In defining a g-force limit, the task group turned to existing amusement ride standards from Australia, the European Union, Germany, Russia, the United Kingdom, and others; experts in the medical field, biodynamics, biomechanics, and astrophysics; and the abundance of research data produced over the last 50 years by universities, the military, and the aeronautical and aerospace industries. After the draft was completed it was submitted to 14 world-renowned experts for review and input. The final g-force limits, which included input from these experts, were then incorporated in F 2291.
Through the efforts of F24, its many subcommittees, task groups and consulting experts, there is now a World Standard for the design of amusement rides and devices. The standard includes relevant design criteria, guidelines, references and g-force limits. The amusement industry is indebted to all 400 members of F24, the members of the World Standard Task Group, its sub-task groups and the experts who provided input, reviewed drafts and commented on the process. //
(1) Source: Heiden Associates. Based on statistics from the Consumer Product Safety Commission (CPSC) and National Sporting Goods Association, amusement ride injury risk is 10 to 100 times lower than most common recreational and sporting activities.
(2) A convenient unit that is commonly used to describe the forces we feel in the g. One g is equal to the force of earths gravity. When standing on earth people normally experience 1 g of acceleration vertically, 9.8 m/s2. A 3-g force is three times the force of gravity. (Acceleration and g-force is used synonymously in this article.)
Copyright 2003, ASTM