NOTE: (c) 1994 by the Paralyzed Veterans of America. All rights reserved. PARALYZED VETERANS OF AMERICA A Guide to Wheelchair Selection How to Use the ANSI/ RESNA Wheelchair Standards to Buy a Wheelchair Peter Axelson, MSME Jean Minkel, MAPT Denise Chesney, MEBME A Guide to Wheelchair Selection How to Use the ANSI/ RESNA Wheelchair Standards to Buy a Wheelchair Peter Axelson, MSME Jean Minkel, MAPT Denise Chesney, MEBME Illustrations by Peter Thomas (c) 1994 by the Paralyzed Veterans of America. All rights reserved. Washington, DC 20006 Printed in the United States of America Library of Congress Cataloging- in- Publication Data Axelson, Peter, 1956- A guide to wheelchair selection: how to use the ANSI/ RESNA wheelchair standards to buy a wheelchair / written by Peter Axelson, Jean Minkel, Denise Chesney; illustrations by Peter Thomas. p. cm. Includes bibliographical references (p. ). ISBN 0- 929819- 06- 3 1. Wheelchairs- Evaluation. 2. Wheelchairs- Standards. I. Minkel, Jean, 1958- . II. Chesney, Denise, 1965- . III. Title. RD757. W4A94 1994 617'. 03- dc20 CIP 94- 32976 ACKNOWLEDGMENTS iv A MESSAGE FROM PVA'S EXECUTIVE DIRECTOR v HOW TO USE THIS GUIDE 1 STANDARDIZED TESTING AND INFORMATION DISCLOSURE 3 Background on Tests and Standards 3 GENERAL CONSIDERATIONS 7 Manual vs. Powered 7 Rigid vs. Folding Manual Wheelchairs 8 Direct- Drive vs. Belt- Drive Powered Wheelchairs 8 Cost 9 INCORPORATING PERSONAL BODY CHARACTERISTICS 11 Body Size 11 Seating 12 Armrest and Headrest 14 Joint Flexibility 17 Propulsion Skill 19 MANUAL WHEELCHAIRS 21 Performance 21 Weight 21 Stability 22 Durability- Fatigue Strength 24 Maneuverability 26 Safety 27 Static and Impact Strength 27 Flammability 28 Wheel Locks 29 Dimensions 30 Overall Dimensions 30 Seating Dimensions 31 POWERED WHEELCHAIRS 33 Performance 33 Speed 33 Obstacle Climbing 35 Range 36 Maneuverability 37 Durability- Fatigue Strength 37 Climatic Test 39 Safety 40 Static and Dynamic Stability 40 Stopping Distance 42 Disengage Force and Nonpowered Push 43 Safety Guards 43 Electrical Systems 44 Static and Impact Strength 45 Flammability 46 Battery Chargers 46 Dimensions 48 Overall Dimensions 48 Seating Dimensions 49 Weight 50 APPENDIX A Additional Information Not Required for Disclosure in the Manufacturer's Technical Product Literature 51 APPENDIX B List of Resources 52 ABOUT THE AUTHORS 53 ABOUT THE PARALYZED VETERANS OF AMERICA 53 Table of Contents iv Acknowledgments The authors wish to acknowledge the Paralyzed Veterans of America (PVA) for its support of consumer education regarding the ANSI/ RESNA* Wheelchair Standards. The U. S. Department of Veterans Affairs (VA) provided funding to support the activities of the Wheelchair Standards Committee. The Paralyzed Veterans of America administratively supported the Wheelchair Standards Committee from its development in 1979 until VA funding was available in 1985. PVA continues to provide travel monies for the chairperson of the committee. The authors also wish to acknowledge the PVA Research and Education Program for providing the additional funding needed to edit, illustrate, and review this guide. We would like to thank the following individuals for their strong commitment to the project and their substantial efforts from initial concept to publication: The authors wish to acknowledge the following organizations and agencies for the substantial expertise and resources they have contributed: The authors also would like to acknowledge the following individuals for their professional reviews prior to final editing for publication: * ANSI- American National Standards Institute; RESNA- an interdisciplinary association for the advancement of rehabilitation and assistive technology Patsy Aldersea, College of Occupational Therapists Raymond Bruce, Paralyzed Veterans of America Lynn Bryant, ABLEDATA David Cantrell, Paralyzed Veterans of America Heather Chester, Oxfordshire Wheelchair Service, Nuffield Orthopaedic Centre Rory Cooper, University of Pittsburgh, VA Medical Center Byrd Dunaway Bonnie Hilburn, Paralyzed Veterans of America Douglas Hobson, University of Pittsburgh J. A. Kanehann, DA International, Ltd. Tricia Karg, ECRI David Kreutz, Shepherd Spinal Center R. Lee Kirby, Dalhousie University Chris Lavanchy, ECRI Sven Linnman, Permobil P. Moore, The Midlands Centre for Spinal Injuries Jim Parkinson Mindy Pasternak Anita Perr William Peterson, National Rehabilitation Hospital Kathleen Riley Faith Saftler Nigel Shapcott Saleem Sheredos, VA, Baltimore Craig Stewart, Paralyzed Veterans of America Terry Sutton, Paralyzed Veterans of America William Walmsley, Department of Health, Wheelchair Evaluation Centre ABLEDATA Beneficial Designs, Inc. California State University at Sacramento Dalhousie University Eastern Paralyzed Veterans of America Everest & Jennings, Inc. Gaymar Industries Helen Hayes Hospital Invacare Corporation National Association of Rehabilitation Information Center National Rehabilitation Hospital Paralyzed Veterans of America Quest Technologies Southwest Research Institute Sunrise Medical Theradyne U. S. Department of Education, National Institute on Disability and Rehabilitation Research U. S. Department of Veterans Affairs Rehabilitation Research and Development Service Prosthetics and Sensory Aids Service Prosthetics Assessment Information Center U. S. Food and Drug Administration University of Pittsburgh University of Tennessee University of Virginia John Bollinger, Deputy Executive Director Dr. Laurance Johnston, Director, Research and Education Rick Glotfelty, Associate Executive Director, Veterans Benefits Department Jeffrey Dolezal, Director of Field Services, Veterans Benefits Department James Angelo, Publications Manager Sarah Ornstein, Graphic Designer A MESSAGE FROM PVA'S EXECUTIVE DIRECTOR While serving in the Army in Vietnam, I sustained a combat- related spinal cord injury. After rehabilitation, I had few options for wheelchairs; the available chairs often were heavy and mobility limiting. Times have changed; wheelchair technology has exploded with a multitude of liberating choices that have greatly enhanced an individual's potential mobility and, therefore, opportunities for integration into society. Today, the wheelchair- user population has many different segments, and manufacturers have developed a variety of products to meet specialized needs. However, with all these new products, consumers often have a difficult time making informed decisions about what's right for them. What may be considered an advantage for one person may be a disadvantage, or even dangerous, for the next person. Clearly, consumers need an easy- to- understand resource to guide them in making purchasing decisions. In 1982, the ANSI/ RESNA Wheelchair Standards Committee was formed to develop standard procedures for testing and comparing wheelchairs, and the Paralyzed Veterans of America (PVA) has been integrally involved with the Committee since its beginning. With support from PVA, Peter Axelson, the chairperson of the ANSI/ RESNA Wheelchair Standards Committee, has guided the development of these standards since 1986. His work has been commendable. However, wheelchair test procedures are technical and often difficult to understand. Thus, what happened next seemed natural, given the productive relationship between PVA and Mr. Axelson. On the basis of PVA's recommendation and support, Mr. Axelson began work on this book, A Guide to Wheelchair Selection: How to Use the ANSI/ RESNA Wheelchair Standards to Buy a Wheelchair. As you will see, the results are outstanding. Mr. Axelson and his coauthors have created a document that you will find informative and enjoyable. With the implementation of wheelchair standards, this book will be an invaluable reference for wheelchair users, therapists, wheelchair dealers, and anyone else who uses, prescribes, recommends, or sells wheelchairs. For the consumer, this is the ultimate guide for selecting a wheelchair. Gordon H. Mansfield Executive Director Paralyzed Veterans of America 1 The purpose of this guide is to explain how you can use the ANSI/ RESNA wheelchair standards to select your next wheelchair. Standards for wheelchairs are currently being adopted by federal agencies. The actual standards are very technical, and at first glance you may not understand how this information will help you select a wheelchair or scooter. This guide is meant to help you understand the purpose for and content of the ANSI/ RESNA wheelchair standards. The guide is divided into five sections: Standardized Testing and Information Disclosure Provides background information on standardized testing of wheelchairs. Discusses how chairs are tested and how information is disclosed. General Considerations Discusses general considerations related to choosing a powered or manual wheelchair. Incorporating Personal Body Characteristics Relates your physical characteristics to the fit of a chair, either manual or powered. Manual Wheelchairs Discusses manual wheelchair test procedures. Powered Wheelchairs Discusses powered wheelchair test procedures. Focuses on three- and four- wheeled scooters as well as full- sized powered wheelchairs. -In the manual and powered wheelchair sections, the test procedures are grouped into three categories: -Performance -Safety -Dimensions For each test procedure, the guide includes: -Reasons why you might need this information -A brief description of the standardized test procedure -How the results of the test will be disclosed in the manufacturer's technical product literature How to interpret the results of the test for your own situation If you are an experienced rider, you may know which elements of performance, safety, and dimension are important to you. If not, or if you are a novice, we highly recommend that you involve other knowledgeable people in selecting your wheelchair. Many rehabilitation specialists have the expertise and training in using these standards and can help you select an appropriate wheelchair. An excellent approach to the wheelchair selection process is to set priorities based on your mobility and seating needs. Setting priorities will help you identify the features that are most important to you and those on which you are willing to compromise. For example, if you live in a small apartment and need to fit your wheelchair into the trunk of your car, you will probably want to look specifically at the overall dimensions, foldability, and weight of the wheelchair. On the other hand, if you use a van and have an accessible apartment or home, you may not need a folding wheelchair. This guide will help you understand the test results that pertain to the factors most important to you. Armed with this information, you will be able to accurately compare products and make an informed purchasing decision. How to Use This Guide 3 . Purchasing a wheelchair can be a harrowing experience and finding the right chair among so many choices might seem impossible. Comparing wheelchair characteristics and performance has been difficult in the past because manufacturers used different standards and procedures to measure and test their chairs. For example, one manufacturer measured seat width from the outside of the seat rails, another measured from inside the rails, and a third measured the distance between the armrest panels. Thus, if you requested a chair with a seat width of 18 inches, the actual distance from the outside of the seat rails could be anywhere from 17 to 19 inches. This inconsistency, as well as a general concern for user safety, led to the development of standardized wheelchair measurements and test procedures. The results of these procedures will provide you with the information you need for true comparison shopping. BACKGROUND ON TESTS AND STANDARDS Since June 1979, the ANSI/ RESNA Wheelchair Standards Committee has been working to provide consumers with objective information about the characteristics and performance of wheelchairs. The committee includes rehabilitation engineers, wheelchair manufacturers, representatives from the Department of Veterans Affairs (VA) and the Food and Drug Administration (FDA), wheelchair users, and wheelchair prescribers. The standards developed by the committee consist of a number of test procedures that apply to all wheelchairs and some that apply only to powered wheelchairs, including scooters. The 18 test procedures are detailed instructions on how to perform the tests or measurements on wheelchairs. Some of the test procedures suggest minimum performance criteria for durability and safety, while others disclose the results of the tests for comparison purposes. The information obtained from the tests is designed to help you make better educated selections. The standardized test procedures also allow you to compare the test results of wheelchairs from different manufacturers. Since many of the test procedures set minimum performance levels, they also help manufacturers produce better products. Standards Increase Your Buying Power The standards are voluntary: manufacturers are not required by law to use the test procedures. However, if consumers start using the results as a basis for wheelchair selection, the manufacturers who do not use the standards may lose sales. VA, the single largest purchaser of wheelchairs in the United States, is adopting the standards for future wheelchair purchasing. Marketplace pressure will most likely encourage overall compliance with the standards. Finding the right chair among so many choices might seem impossible Standardized Testing and Information Disclosure 4 A Guide to Wheelchair Selection More About the Standards To gain the maximum benefit from the standardized testing, both consumers and professionals must understand how to use the information. The following is a list of the test standards, listed by their ANSI/ RESNA number designation, that apply to all wheelchairs, with a brief description of the test procedure. Part 00: Nomenclature, Terms, and Definitions. This section establishes the terms and definitions used in the test procedures. Part 01: Determination of Static Stability. This test determines how stable the wheelchair is when it is resting on a sloped surface. Part 03: Determination of Effectiveness of Brakes. This test determines how well the wheel locks (parking brakes) prevent the wheelchair from rolling on a sloped surface. This test also determines the minimum stopping distance of a powered wheelchair at its maximum speed. Part 05: Determination of Overall Dimensions, Mass, and Turning Space. This section addresses the overall length, width, height, folded width, weight, and turnaround space of the chair. Part 07: Determination of Seating and Wheel Dimensions. This section addresses the dimensional information needed to fit a chair to a rider. Standard methods of measurement eliminate the problems that result from variations in measurement methods. Part 08: Static, Impact, and Fatigue Strength. This section addresses the strength and durability of a wheelchair. Part 11: Test Dummies. This section addresses the dimensional and weight specifications of the dummies to be used when conducting the tests. Part 13: Determination of the Coefficient of Friction of Test Surfaces. This test describes the roughness or slipperiness of the surface to be used for testing. Part 15: Guidelines for Information Disclosure. This section tells what information manufacturers are required to disclose and how it should be disclosed in their product literature, if they choose to comply with the standards. Part 16: Determination of Flammability. This test addresses the extent to which upholstery will burn and how fire retardant the upholstery is. Part 93: Wheelchair Maximum Overall Dimensions. This section establishes suggested maximum dimensions of a chair for other organizations to use as guidelines for architectural accessibility. Part 7930: Type Classification Based on Appearance Characteristics. This section describes the five- number code used to classify a wheelchair based on appearance characteristics. The following is a list of test procedures that apply to powered wheelchairs only: Part 02: Determination of Dynamic Stability of Electric Wheelchairs. This section addresses how stable a powered wheelchair is when starting up a hill, braking down a hill, and turning on a level surface. Part 04: Determination of Energy Consumption of Electric Wheelchairs. This test addresses the energy consumption of a powered wheelchair on a standardized track. Part 06: Determination of Maximum Speed, Acceleration, and Retardation for Electric Wheelchairs. This section addresses the maximum speed in forward and reverse. It also determines the minimum time from stationary to maximum speed (acceleration) and from maximum speed to a complete stop (retardation). Part 09: Climatic Tests for Electric Wheelchairs. This section addresses the effects of rain and temperature changes on the functioning of a powered wheelchair. Part 10: Determination of Obstacle- Climbing Ability of Electric Wheelchairs. This test determines how high an obstacle a powered wheelchair can climb over. Part 14: Testing of Power and Control Systems for Electric Wheelchairs. This test addresses safety, how well the fail- safe braking mechanism works, the force required to actuate the controls, and other issues related specifically to powered wheelchairs. 5 Standardized Testing and Information Disclosure How Chairs are Tested The ANSI/ RESNA Wheelchair Standards are specific instructions on how to perform the test procedures. Some of the test procedures have minimum performance requirements, including the flammability and climatic tests, the static and impact strength tests, and the power and control systems tests for powered wheelchairs. The results of the minimum performance tests are either pass or fail. These tests ensure minimum performance and safety of the product. Most of the test procedures are performance tests that produce quantified information about a chair. The results give information for comparison purposes only; there is no pass or fail determination. These comparisons are meaningful because, for the first time, each manufacturer uses the same tests. Until now, different manufacturers described their wheelchairs using different terms. By comparing test results of different chairs, you can begin comparative wheelchair shopping. Most of the tests are conducted with a test dummy in the chair to represent the weight of a person. The results for chairs tested in this "loaded" condition more closely approximate the fit and performance of a chair when it is actually occupied. Your own body size, body proportions, and riding style may affect the actual fit and performance of a chair. For wheelchair components that are adjustable, the manufacturer adjusts the wheelchair configuration and controls to obtain the extreme range of out comes for a specific test procedure. For example, rear axle position and other adjustable features affect the stability of a chair. In this case, the manufacturer tests the wheelchair with its rear wheels and other adjustable features in both the least and most stable configurations. These results give a range of tipping angles that reflects the least stable and most stable configurations that can be obtained by adjusting the rear wheels and other features of the wheelchair. On a powered wheelchair with an adjustable controller, the manufacturer will disclose a range of stopping distances to reflect the adjustability of speed and retardation (deceleration). How Information is Disclosed Manufacturers that wish to comply with the ANSI/ RESNA Wheelchair Standards must comply with Part 15: Guidelines for Information Disclosure, which specifies which test results must be contained in the pre- sale technical product literature. A list of the additional tests that the manufacturer is required to perform is contained in appendix A. The manufacturer is not required to disclose the results of these additional tests in the technical product literature, but the consumer can request this information. To be in compliance with the ANSI/ RESNA test procedures, manufacturers are required to disclose certain information about the chair in their pre- sale technical product literature Testing of wheelchairs has become more sophisticated over the years 6 A Guide to Wheelchair Selection The test results of particular procedures are disclosed as performance values, which at first may have little or no meaning to you. For example, a manufacturer may disclose the rear tipping angle of a wheelchair, but there is no minimum performance value available for comparison at this time. However, you can look up the tip angle or the range of tip angles for a specific wheelchair with which you have experience, then look at the tip angles of other wheelchairs and figure out how these chairs will perform compared with the chair you know. For example, suppose your current wheelchair has a rear tip angle of four degrees. You can determine if the wheelchair you are considering is more or less tippy than your current chair by finding out if its rear tip angle is greater or less then four degrees. As you gain experience using one wheelchair, the information about other wheelchairs will become more meaningful to you. Note: The performance ratings are usually based on testing only one wheelchair. The results disclosed represent the maximum performance of a new wheelchair tested without failure. The performance you get from your wheelchair will vary depending on your body size and proportion, physical strength, abilities, skills, and riding habits and on environmental conditions. 7 MANUALVS. POWERED Rehabilitation programs used to emphasize that if it was possible for you to push a manual wheelchair, you should do so. The saying was, "Use it or lose it." However, many people with marginal ability to use a manual wheelchair are finding that they deplete all their energy resources just trying to get where they want to go. Once they get there, they have no energy left to do what they want to do. Worse yet, people with 20 or 30 years of experience pushing a manual wheelchair are realizing that their shoulders are worn out as a result of the years of "using it" and not "losing it." Should healthy manual wheelchair riders spend some time in a powered wheelchair? To answer this question, do some self- examination. Ask yourself which type of mobility meets your needs. Some Reasons to Select Manual Mobility -You have sufficient upper body strength and overall endurance to propel your wheelchair all day. -Reducing the weight or increasing the maneuverability of the wheelchair would enhance your independence. -Some of your daily activities are easier to perform in a manual chair. -A manual wheelchair is smaller, lighter, and less expensive to maintain and repair. -You are not experiencing chronic pain in your arms or shoulders. Some Reasons to Select Powered Mobility (including Scooters) -You have insufficient endurance or functional ability to propel a manual wheelchair independently. -You need to conserve energy during long- distance wheeling to work or school -Powered mobility would enable you to be more independent in your daily living, work, and recreational activities -You have access to personal or public transportation that accommodates a full- sized powered chair or scooter for longer distance travel. Many powered wheelchair riders have a manual wheelchair to use when a powered wheelchair is inconvenient. When traveling, a powered wheelchair user may use a manual wheelchair and have a person help with mobility. Other users may rely on a manual wheelchair at home and at work and use a powered wheelchair for traveling to and from work. There is something to be said for the use of a powered wheelchair to prevent overuse of the shoulder muscles, although this option is not often discussed. Financial considerations are In some environments, a manual wheelchair may not leave you with the energy that you will need when you get to your destination General Considerations 8 A Guide to Wheelchair Selection important as well, since powered wheelchairs are expensive. Whether the primary wheelchair is powered or manual, a backup manual wheelchair should be available in the event of breakdown of the main wheelchair. RIGID VS. FOLDING MANUALWHEELCHAIRS If you plan to use a manual wheelchair, the first decision you have to make is whether it should be rigid or folding. Nonfolding fixed- frame chairs are more rigid, where folding chairs tend to have a little more flex in the frame. This flex can be an advantage when you are traveling over slightly uneven surfaces, because all the wheels of the chair tend to stay on the ground. When you use a rigid wheelchair on an uneven surface, one wheel often lifts off the ground. However, on a hard floor surface, a rigid- frame chair gives a more responsive feeling, since all the energy you expend goes into propulsion, and none goes into flexing the frame of the chair. Many people prefer the aesthetics of a rigid frame, although both types are available in lightweight models and in a variety of colors. Some of the advantages and disadvantages are listed to the right. ADVANTAGES DISADVANTAGES -Rigid frame -Frame design requires fewer -Requires removal of quickcomponents and thus has more release rear wheels for loading strength for a given amount of weight into car -Usually a lighter weight chair than-May feel bumpier on uneven a similarly equipped folding chair surfaces -Fewer removable parts - Does not fold into as small a package for stowing in car or -Required to meet National Wheelchair airplane Basketball Association specifications -Seat- to- back angle is often adjustable Folding frame Folds into compact package for stowing -More moving, adjustable, and in car or airplane removable components -Flexes to enable all four wheels to -May not meet rider's sports stay on the ground when riding on or leisure activity needs uneven surfaces -Seat- to- back angle usually -Can be folded and stowed without not adjustable removing parts -Lateral stability can decrease as the chair flexes or starts to fold DIRECT- DRIVE VS. BELT- DRIVE POWERED WHEELCHAIRS When the motors are mounted directly to the drive wheels with only gears in between, the system is called a direct- drive system. When belts connect the motors to the drive wheels, the system is called a belt- drive system. Most wheelchairs are only available one way or the other. Keep in mind when comparing two scooters that one may have a direct- drive system while the other may have a belt- drive system. Full- sized powered chairs are also manufactured with either a direct- drive or a belt- drive system. Like the rigid- frame manual wheelchair, the direct- drive system has no "flex" or slack. The drive wheels respond directly to the actions of the motors. The belt, on the other hand, introduces a slight delay between the action of the motor and the wheel. Depending on your trunk balance, you may find the delay in a belt- driven chair provides a more comfortable ride. Unfortunately, belts can slip if they are not properly adjusted or if they are wet, and the rear wheels will not always respond when you want them to. You must look at the advantages of direct drive versus belt drive and make the best choice for your needs and your environment. Getting a folding wheelchair into and out of a car can be quicker than a rigid- frame chair. However, many riders prefer the performance of a rigid- frame chair on hard surface floors 9 General Considerations Some of the advantages and disadvantages of the two drive systems are listed below. ADVANTAGES DISADVANTAGES Direct drive -Requires little maintenance Can be noisy during operation -No exposed parts to get dirty -Gears wear if not properly wear lubricated Belt drive -Belts can be easily replaced -Chair will drive in a circle if a belt breaks -Generally quiet during operation -Belts can slip when wet, reducing control -Can provide a smooth ride Generally requires more maintenance May require adjustments if there is a change in temperature Belts can be noisy during start- up COST Seating and mobility professionals can provide a thorough clinical evaluation of your needs, environment, size, and functional strengths and limitations to help you choose the appropriate wheelchair. In addition, the rehabilitation facility may have a variety of wheelchairs on hand to demonstrate the "latest and greatest" in design and components. A proper clinical evaluation and knowledge of available components may prevent costly mistakes. Many wheelchair users have received chairs that did not fit or did not meet their functional needs as a result of an uninformed decision. In most cases, the rehabilitation center will assemble and adjust the chair to fit you, and training is often available through the center or the wheelchair supplier to help you learn the performance characteristics of the chair. If you feel you can bypass seating and mobility professionals because you have enough personal experience, you may be able to save money by purchasing the wheelchair directly from a mail order house or with cash through a local supplier. As with any mail order purchase, you will forgo local support, including warranty repairs, assembly, setup, and adjustment to fit your body, abilities, and skills. Such a purchase also will not include training, which you might need if the new wheelchair has very different performance characteristics than your previous one. Many users are choosing lower maintenance direct- drive chairs despite some drawbacks 11 BODY SIZE Just knowing your height and weight is not enough to determine the appropriate dimensions of your wheelchair. In order to achieve the best fit, you also need to know the dimensions of your body in a seated position. When measuring your body size, it is helpful to sit in a wheelchair that is as close to the correct size as possible. If you are ordering a wheelchair with sling upholstery, you should be measured while sitting in a chair with sling upholstery. If you are ordering a wheelchair with rigid seat and back surfaces, you should be measured sitting in a wheelchair with a rigid seat and back, or at least on a surface with similar characteristics. If you will be using a seat cushion, sit on the same type and size of cushion you will use in the new chair. Be sure to consider the seat cushion as part of your body while making the measurements. If you sit on a cushion that is lower or higher than the one you will be using in your new chair, the measurements will be incorrect. The measurements you will use are: -Seat width -Seat depth -Seat surface height -Backrest height -Footrest- to- seat distance If you use armrests and/ or a headrest you will need: -Armrest height -Front of armrest to backrest distance -Armrest length -Front location of armrest structure Distance between armrests Headrest height Until now, figuring the dimensions of a wheelchair to fit an individual was a bit of a nightmare, because there was no standard measurement method. Each manufacturer had its own way of making measurements. Also, all manufacturers measured their chairs empty, although the size of the chair may change when a person sits in it. The fabric seat and back upholstery may give, pulling the two sides of the chair together, thus changing its size. The ANSI/ RESNA test procedures require that the wheelchair be measured "loaded" with a weighted test dummy. The test dummy sizes represent the size and weight of the intended rider: large adult (220 lbs/ 100 kg), adult (165 lbs/ 75 kg), small adult (110 lbs/ 50 kg), and child (55 lbs/ 25 kg). Specifying a chair to fit you will be much more accurate when working with dimensions that represent the size of an occupied chair. Although figuring out the dimensions of a wheelchair can still be pretty challenging, you will find that the test procedures provide more accurate information and that measurements from different manufacturers can be compared. Incorporating Personal Body Characteristics SEATING Seat Width Generally, to enhance accessibility, the width of a chair should be as narrow as possible without causing pressure on the rider's hips. An increase in seat width usually results in an increase in the overall width of the chair. You might select a wider wheelchair if you wanted a chair that was more stable sideways. Another consideration is the type of clothing that you will be wearing. If you generally wear a suit or jacket, you may want a little extra room for tucking in your clothing on the sides. Seat Depth The seat should be long enough to provide adequate leg support, which creates better weight distribution. If your legs can support weight, a longer seat depth will spread your weight out more over your thighs. This means that the amount of weight on your bony prominences will be decreased, thus decreasing the risk of pressure sores. If the seat is too long, however, the front edge will catch the back of your knees. The effective seat depth of a chair with a fabric backrest will measure longer than one with a rigid back support surface. If you will be adding a rigid back support to a wheelchair with sling upholstery, the seat depth of your chair may change. It is a good idea to install the back support on a wheelchair similar to the one you will be ordering to determine how much the seat depth will change. The seat depth is increased even more when a chair is equipped with legrests that have calf supports. Calf supports hold the legs forward of the front edge of the seat. If this is not taken into consideration when ordering the wheelchair, this may prevent you from positioning your buttocks against the backrest and would then cause you to sit in a slumped sitting posture. Calf Supports Seat Depth Seat Width 12 A Guide to Wheelchair Selection 13 Incorporating Personal Body Characteristics Seat Surface Height The wheelchair seat must be high enough to accommodate the length of your legs and yet low enough so that your legs will fit under tables. Some users prefer to sit up higher so they are more eye- to- eye with people sitting or standing next to them. If the chair has a fabric seat, the seat surface height will measure a bit lower than one with a rigid seating surface. The distance disclosed by the manufacturer will not include the height of a seat cushion. If you will be using a seat cushion, determine your appropriate wheelchair seat height while sitting on that seat cushion. Sit in a similar wheelchair and then measure to the bottom of your seat cushion. If the seat height is too low and you use footrests, the footrests may not have enough ground clearance and may scrape the ground at curb cuts. A seat that is too high may make transferring into and out of your chair more difficult. Manual wheelchair users should keep in mind that changing the seat height will also change your body's relationship to the drive wheels and may affect your ability to push your chair. Ahigher seat will make it harder to reach the pushrims, while a lower seat will allow you to reach more of the pushrims. The seat height is very important for people with hemiplegia or others who propel their chairs using their feet. If you propel the chair with your feet, you might need a lower seat. Backrest Height The height of the backrest depends on the rider. Some wheelchair riders want a low backrest for enhanced upper body movement or because they like the way it looks. Higher backrests help support riders who have less upper body balance. Regardless of the backrest height, be sure that the back posts or push handles do not interfere with your arm movements while you are wheeling. The backrest height disclosed by the manufacturer will not include the thickness of the seat cushion. The backrest height is measured from the seat surface of the wheelchair. When determining your backrest height, make sure you are seated on the seat cushion that you intend to use. Measure from the surface on which the seat cushion is resting. Since this measurement is made from the wheelchair upholstery surface, the backrest height measurement will be slightly higher for a wheelchair with sling upholstery than for a chair with a rigid seat. Backrest Height Seat Surface Height at Front Edge 14 A Guide to Wheelchair Selection Footrest- to- Seat Distance The manufacturer will measure and report the footrest- to- seat distance without a seat cushion on a loaded wheelchair. To determine if the wheelchair will accommodate your leg length, sit on your cushion in a wheelchair with a similar seating surface. Measure from the bottom of the shoes that you normally wear to the front edge of the seating surface just beneath your cushion. If the footrest length is adjustable, the manufacturer will indicate the range available for a particular chair and footrest. If the range does not meet your needs, remember that footrests are usually available in a variety of styles; a different footrest may provide the range of adjustment necessary to accommodate your leg length. Sometimes changing the footrests is not enough. If you have very long or very short legs, you may need to look for a different frame style. Tall or short frames, for proportionately taller or shorter people, are available in some models. To accommodate long legs, you might also need a higher seat or a greater seat- to- leg angle. Once the footrest is adjusted for you, you should have at least two inches of clearance under your foot pedals to save you from hitting the bottom of curb cuts with your foot pedals. Footrest clearance and leg length must be considered before selecting a seat height. Footrests are available in a wide variety of styles and variations. The type of footrest that is appropriate for you will depend on your size, needs, and preferences. The following features may be available from the manufacturer. FOOTRESTS DESCRIPTION Adjustable length Usually a standard feature Accommodates a range of leg lengths Swing away, detachable Necessary for some riders to be able to transfer or to put the chair in the car Flip- up -Required for folding wheelchairs -Facilitates some types of transfers Folding footplate Non- flip- up -Folds for storage Impact guard -Hard plastic, wheel- shaped bumper on the outer front edge of the footrest Useful for pushing open doors -Prevents the footrest from catching on obstacles, such as curb cuts and doors, and from digging into floor surfaces Required for indoor basketball wheelchairs Elevating -Usually an optional feature -Usually enables elevation of one leg at a time 90�- 90� platforms -Accommodates shorter leg lengths -Usually used for children Rigid single unit -Usually found on rigid- frame wheelchairs -Generally much stronger Calf support strap -Prevents the feet from falling back underneath the chair Calf support -Usually provided with elevating leg rests -Prevents the legs from slipping back underneath the wheelchair ARMREST AND HEADREST If you use armrests, several measurements in the test procedures may be of interest to you: armrest height, front of armrest to backrest distance, and the armrest length. Armrest Height The armrest height is an important dimension to consider. The manufacturer reports the distance from the top of the armrest to the top of the loaded seating surface of the wheelchair. The measurement for a wheelchair with sling upholstery will be different than for one with a rigid seating surface. To determine the armrest height you need, sit on your seat cushion in a chair with a seating surface like the one you will be purchasing. Hang your arm down at your Footrest- to- Seat Distance 15 Incorporating Personal Body Characteristics side, bend your elbow 90 degrees, and measure the distance from the bottom of your elbow down to the seating surface of the wheelchair beneath the cushion. The armrest height of a wheelchair with a fixed- height armrest is given as a single value. For wheelchairs with adjustable- height armrests, a range of heights is given. Some adjustable armrests have infinite adjustments within the range, while others have a limited number of preset height adjustments. Armrests that are too high can cause your shoulders to be elevated; armrests that are too low can contribute to a slumped posture or even shoulder subluxation in riders without good shoulder muscles. Make sure your armrest height is appropriate to prevent shoulder problems and further complications caused by poor posture. If you use armrests, you may find the following additional measurements helpful. Front of Armrest- to- Backrest Distance The distance from the backrest to the front of the armrest is important if you use the armrests to transfer into or out of your chair. If the armrests do not extend far enough forward, they may not provide the support you need. If the armrests are too far forward, they may prevent you from getting close to a desk or table. This measurement will be slightly longer for a wheelchair with sling upholstery. Armrest Length The length of the padded part of the armrest is the armrest length. When you sit back in the chair, the armrest pad should reach far enough forward from the backrest to support your arm in a comfortable position. If you use a lap tray, the length of the armrests should provide enough support for the tray. Armrest Length Front of Armrest- to- Backrest Armrest Height Front Location of Armrest Structure The front location of the armrest structure is the distance from the backrest to the most forward part of the armrest. This distance is measured at a height of about 27 inches from the ground and thus indicates how close you will be able to pull up to a desk or table. The distance from the backrest to the front location of desk- style armrests is shorter because they are specifically designed to enable you to pull up closer to a desk, writing surface, or table. Distance Between Armrests The distance between the innermost edges of the armrests is only measured on wheelchairs with fixed armrests. Armrests welded directly to the frame of the chair tend to limit the maximum available seat width at the height of the armrest pads because of the width of the support pads. Armrests are available in many styles and sizes. Armrest measurements may vary if you change the type of armrest on the wheelchair. The type of armrest that is best suited for you depends on your size, your needs, and your preferences. The following armrest features may be available from the manufacturer. ARMRESTS DESCRIPTION Adjustable -height -Desirable for setting the armrests at the height you need -The height can vary to facilitate transfers Clothing guard -Prevents your clothing and your body from touching the wheel -Available in either a fabric or rigid style Desk- style -Shorter armrests that enable you to pull up close to a desk, writing surface, or table Fixed -Cannot be removed from the wheelchair Full- length -Extend at the same height from the backrest forward Pivoting -Can be pivoted into another position (usually behind the back posts) -Can be pivoted out of the way for transfers Removable -Can be removed to facilitate transfers Sloping -Slope downward toward the front of the wheelchair -Reduced profile for approaching a desk, writing surface, or table Wraparound -Often create a narrower overall wheelchair width without significantly decreasing the width between the armrest panels The rear lock on the armrest may be farther back on the chair and more difficult to reach Headrest Height If a chair comes with a headrest, the standards require that the manufacturer disclose how high the center of the headrest is above the seat upholstery. If the headrest is adjustable, the test results will indicate the range of heights at which it can be positioned. To determine your headrest height, sit on your seat cushion in a chair with a seating surface like the one you will be purchasing. Measure from the back of your head down to the seating surface beneath your cushion. Distance Between Armrests Front Location of Armrest Structure 16 A Guide to Wheelchair Selection 17 Incorporating Personal Body Characteristics Another measurement that may be of interest to you is the distance the headrest is in front of the backrest. Manufacturers are not required to disclose this measurement in the pre- sale technical product literature, but you can request it. This measurement will indicate if the headrest is directly in line with the backrest or if it can be positioned in front of or behind the backrest. It may be a single value or, if the headrest position is adjustable, a range of values. JOINT FLEXIBILITY In addition to your size, the flexibility of your joints (how far your arms and legs bend and straighten) will influence the fit of your chair. Your ability to maintain your sitting balance will also affect your choice. The flexibility of your hips affects the seat- to- backrest angle you need. In the standards, the seat- plane angle refers to the slope of the seat. Some riders have found that wedged or squeeze frames (chairs with a rearward slope to the seat) help with balance and stability. If you keep your backrest upright (not reclined) and increase the rearward slope of your seat, you will need to bend your hips more to fit into the chair. If you do not have good hip flexion, too much squeeze can cause pressure problems because your body cannot bend enough to fit into the chair. If you are not very flexible, you may want to look for a chair with an adjustable backrest angle. If you recline the backrest just a little, the angle between the seat and the backrest will more closely match the angle between your thigh and your trunk. Some powered wheelchairs are available with a power recline feature. This option may be necessary if you must perform independent weight shifts and repositioning for increased sitting tolerance and cannot shift weight by yourself. A power recline feature can also eliminate the need for transfers to bed for rest or catheterization. Quick position changes can help reduce spasticity, your body's response to low blood pressure, and dysreflexia. It is also important to know the flexibility of your knee and ankle joints. Many wheelchair manufacturers offer chairs with the foot pedals closer to the front edge of the seat. These "tighter" footrests reduce the overall length of the chair and make it easier to get closer to things in your environment. To fit into these tighter wheelchairs, you need good knee flexion. Leg- to- Seat Surface Angle The smaller the leg- to- seat surface angle, the more flexion or bend you will need at your knees. If you have limited knee movement, look for the angle that most closely matches the angle between your thigh and lower leg. Note: Many wheelchair manufacturers used to measure this angle using a different method. They were not measuring the leg- to- seat surface angle as illustrated here. When this angle is measured correctly, it will almost always be greater than 90 degrees. Headrest Height Seat- Plane Angle The seat- plane angle can be positive, negative, or zero. A zero seat- plane angle means that the seat is level. A positive seat plane angle means that the seat slopes downward to the rear and that the front edge of the seat is higher than the back edge. Seats with a positive seat- plane angle require good hip flexion. A negative seat- plane angle means that the seat slopes forward and the front edge of the seat is lower than the back edge. Seats with a negative seatplane angle require good trunk balance. Some wheelchair users like sitting with their knees up high on a wedge to increase their trunk stability. However, while doing this increases trunk stability in the short term, it tends to round your spine and, in the long term, can lead to back pain. Backrest Angle A zero backrest angle means that the backrest is upright or vertical. A positive backrest angle means that the backrest is reclined. Backrests that can be reclined quite far have large positive angles. The larger the angle, the more you will lean back in your wheelchair. A reclined position accommodates less flexible hips. Backrests that can be adjusted into a forward- leaning position have negative backrest angles. A forward- leaning backrest requires greater hip flexion. The more vertical the backrest angle, the more you will sit up straight in your wheelchair. Some wheelchair users like sitting in a chair with a negative backrest angle. If the backrest angle is adjustable, the manufacturer will give a range of angles. Backrest Angle Seat- Plane Angle Leg to Seat Surface Angle 18 A Guide to Wheelchair Selection + Horizontal Reference + Vertical Reference 21 PERFORMANCE There are hundreds of manual wheelchairs on the market today. As you begin the process of comparison shopping, you will want to know exactly how your wheelchair will perform. The ANSI/ RESNA Wheelchair Standards address four aspects of the wheelchair that affect its performance: Weight Stability Durability- Fatigue Strength Maneuverability For these performance tests, the manufacturer gives the results as specific values. There are no minimum performance values; therefore, no wheelchair fails these tests. If the chair tips over backward on a slope of only one degree, that is what is reported. It will be up to you to determine if the wheelchair's performance is compatible with your abilities, lifestyle, and environment. Until you understand exactly what these performance values mean, your experience with using a particular wheelchair will help you understand how other wheelchairs will perform. By comparing test results, you will learn how other wheelchairs perform compared with the wheelchair you currently use. The information provided by these tests will enable you to make true comparisons among wheelchairs, because each chair will be tested the same way. WEIGHT How heavy is the chair? Whether you prefer a tank- style chair or a super lightweight chair, you will want to know and compare the weights of several different chairs. The weight of the chair may also be important if you need to stow it in the back of your car when you drive, or if the person assisting you needs to lift the chair into and out of the trunk. Weight Test Procedure ANSI/ RESNA Wheelchair Standard Part 05: Determination of OverallDimensions, Mass, and Turning Space The total weight of the wheelchair equipped with standard armrests, legrests, wheels, and casters is measured. The weight of your wheelchair is not just an issue for you as the rider Manual Wheelchairs 22 A Guide to Wheelchair Selection Disclosure Format (as reported by manufacturers) Name of Test Test Result Total mass of wheelchair with accessories ___ lb (___ kg) Additional information not required for disclosure in the product literature: Mass of each removable component of the wheelchair ___ lb (___ kg) Interpretation of Results- Weight The results of this test procedure help you to compare wheelchairs manufactured by different companies. Using these results, you will be able to identify the lightweights and the heavyweights. Most important, you will be able to find the chairs that fall within the weight range you desire. This information indicates how the wheelchair will perform and whether you or the person assisting you will be able to load it into a car. Knowing the weight of each removable component of the wheelchair may also help in your selection process. If fully equipped wheelchairs (with standard armrests, legrests, wheels, and casters) are too heavy to lift, you may choose a wheelchair based on the weight of the heaviest component, which is usually the frame. This information is not required for disclosure in the product literature, but it is available upon request from the manufacturer. Using the weights of the wheelchair and each of the components, you can calculate the weight of the chair equipped the way you like it. One component that significantly changes the weight of the wheelchair is the main drive wheels. Depending on the chair, either spoke or mag wheels are standard. In general, spoke wheels are lighter, but they require more maintenance, since the spokes can become loose or break. Mag wheels are heavier but are virtually maintenance free. The tire you choose also can make a difference in the weight. A lightweight, Kevlar- reinforced tire with a thin tube can be significantly lighter than a heavy rubber tire with a thick- walled tube. Your own body weight represents a large percentage of the combined weight of the wheelchair and rider. Therefore, shaving off a pound here and there on the wheelchair may not result in a significant difference in wheelchair performance, but it may be necessary if you need to load it into your car. STABILITY How tippy is the chair? Let's face it, the world is not flat. Hills, ramps, curb cuts, and sidewalks with side slopes are just a few of the reasons you might want to know how tippy your wheelchair will be. The stability of the wheelchair standing still not only indicates how tippy the chair is when at rest; it also indicates how stable the chair will be when it is moving. If you have a lot of rider experience or are very active, you may prefer a chair that tips back into a wheelie position with just a slight shift of your weight. If you do not have much experience or upper body mobility, you may want a more stable, less tippy chair. Stability Test ProcedureANSI/ RESNA Wheelchair Standard Part 01: Determination ofStatic Stability The wheelchair is placed on a standardized test surface with a weighted test dummy positioned in the chair. The test surface is tilted with the wheelchair facing uphill, downhill, and sideways. The angle at which the wheels of the wheelchair lift off the test surface is recorded in degrees. Disclosure Format (as reported by manufacturers) Name of Test Test Result Facing downhill / brakes on tips at ___ degrees of slope Facing uphill / brakes on tips at ___ degrees of slope Facing sideways / brakes on tips at ___ degrees of slope Other critical direction / brakes on tips at ___ degrees of slope Having the ability to lean forward in your wheelchair allows you to negotiate steeper ramps 23 Manual Wheelchair Interpretation of Results- Stability During the test, the wheel locks are engaged, simulating you, the wheelchair rider, holding onto the handrims on an incline. The best way to create the same effect during testing is to apply the wheel locks. The smaller the uphill tip angle, the tippier the wheelchair. This means that the chair started to tip when the platform was tilted a small amount. A wheelchair that tips more easily will be easier to maneuver and will have less tendency to turn downhill on side slopes. Because a larger percentage of your weight is on the rear wheels, the wheelchair will have greater traction. However, the wheelchair will be less stable and more likely to tip over backward when you go uphill unless you can adjust your body weight by leaning forward. When your body weight is over the main drive wheels of your wheelchair, the chair is tippy. When you shift your weight forward- either by leaning forward or by moving the main drive wheels back- you make the wheelchair less tippy. Conversely, a greater uphill tip angle means that the platform was tilted more before the chair's wheels lifted off the platform. Chairs with larger tip angles are less tippy, harder to maneuver, and have a greater tendency to turn downhill on side slopes. Less weight is distributed over the rear wheels, which may result in rear wheel slippage when you go down an incline. A chair with a smaller downhill tip angle is less stable going forward. During testing the platform is tilted, raising the back end of the wheelchair. This simulates a wheelchair facing downhill. When you travel down ramps and curb cuts, you may need to lean back in the chair to prevent it from tipping forward. Unless you have good balance and a low- back chair, you may not be able to lean back in the wheelchair. If you cannot lean back in the chair, you should probably consider a chair that is more stable in the forward direction: one with a greater downhill tip angle. If the manufacturer reports a range of tip angles, this indicates that the position of the rear wheel, front caster, and/ or other features is adjustable. Some wheelchairs have only distinct vertical and/ or horizontal positions in which the main drive wheels can be located. Other chairs offer an infinite number of horizontal axle positions. Adjusting the rear wheel forward will decrease the wheelbase and will decrease the stability of the chair in the rearward direction. Moving the rear wheel backward will increase the wheelbase and consequently increase the rearward stability of the chair. Changing the vertical position of the rear wheel changes the seat height and angle and may either increase or decrease stability, depending on the location of the center of mass of the system. The fore- aft adjustment of the caster, if available, changes the length of the wheelbase. The smaller the wheelbase, the tippier the chair in either the forward or rearward direction. Many users increase the tippiness of their wheelchairs as they gain more rider experience. Achair with a smaller sideways tip angle is less stable side to side. A chair with a smaller sideways tip angle is more likely to tip over sideways when you travel across surfaces with steep cross slopes or lean over the side of the chair. A range of sideways tip angles usually indicates that the amount of camber is adjustable. Camber is the angling of the main drive wheels out at the bottom of the chair. Some manufacturers allow users to customize their chair by changing the camber. Increasing the camber will make a wheelchair more stable from side to side but will also increase the overall width of the chair and make it difficult to get through narrow doorways. Camber also moves the pushrims in closer at the top of the main drive wheels, which will enable you to reach your pushrims easier and may actually prevent you from hitting your fingers as you pass through doorways. Note: Remember that the tip angle is not an indication of the quality of the wheelchair, but a matter of personal preference. To give you an indication of the angles of the slopes you may encounter in public places, accessible environments that comply with the Americans with Disabilities Act Accessibility Guidelines (ADAAG) will not have slopes Extra camber on your wheelchair makes your chair a little more stable on cross slopes and moves the handrims a little closer in on the sides 24 A Guide to Wheelchair Selection greater than 1: 12 (4.8 degrees). Therefore, a wheelchair with an uphill tip angle of greater than 5 degrees will probably not tip backward when you climb a public ramp, especially if you can lean forward in the wheelchair. If, however, the downhill tip angle is close to 5 degrees, you may end up performing somersaults while trying to wheel down the ramp, unless you can shift your body weight by leaning backward. The disclosed test results apply only to the wheelchair as tested by the manufacturer. If you want different main drive wheels or casters, the stability of the chair may change. For example, smaller diameter rear wheels or larger front casters will tilt the wheelchair to the rear and possibly decrease its stability going uphill. Anti- tippers are extra little wheels designed to prevent a wheelchair from tipping over backward. They will affect the stability of the chair when going uphill. Although anti- tippers prevent the wheelchair from tipping, many riders do not like using them. They restrict the chair's ability to go over obstacles, because they can get caught on the obstacle. In addition, it is almost impossible for the wheelchair rider to adjust anti- tippers from the down/ engaged position to the up position or vice versa while sitting in the wheelchair because they are difficult to reach. DURABILITY- FATIGUE STRENGTH How long will the wheelchair last? A wheelchair is a major purchase; the last thing you want is a chair that falls apart after a week of taking it over bumps, up and down curbs, in and out of the car, and through all the other activities you do in your chair every day. How long will a wheelchair last? The durability of the chair is important, whether you are a very active rider or not. If a wheelchair component breaks, you could be hurt or stranded somewhere. Fatigue tests are intended to determine the durability of the wheelchair and its components by subjecting them to a large number of low- level stresses, similar to the forces the chair is subjected to in daily use. Durability- Fatigue Strength Test Procedure ANSI/ RESNA Wheelchair Standard Part 08: Static, Impact, and Fatigue Strength Tests The wheelchair, loaded with the test dummy, is positioned on a double drum fatigue test machine. This machine consists of two cylindrical drums that are rotated by an electric motor. The wheelchair is placed on these cylindrical drums and it rolls as the drums turn. Slats attached to the drums cause the chair to bump as it rolls. One cylinder turns more quickly than the other, making the bumping uneven. This bumping simulates a user riding over rough ground. The chair rolls on the cylinder for a set number of cycles. A second fatigue test is the curb drop test. In the curb drop test, the loaded wheelchair is dropped in a free fall manner from a height of approximately two inches. One curb drop fatigue test is performed for every 30 cycles on the double drum fatigue test machine. The manufacturer is asked to disclose the number of double drum and curb drop cycles that the wheelchair makes it through without failure. Disclosure Format (as reported by manufacturers) Name of Test Test Result Double drum test ___ cycles Curb drop test ___ cycles Interpretation of Results- Durability If the manufacturer discloses that its chair has been tested with a large number of double drum and curb drop cycles, it means that the chair is more durable than one that only passed a smaller number of test cycles. However, if the man Anti- tippers can literally leave you spinning on your wheels 25 Manual Wheelchair ufacturer discloses that its chair has been tested to a smaller number of double drum and curb drop cycles, it may only mean that they stopped testing after that many cycles. Unfortunately, the test procedures do not require the manufacturers to test their wheelchairs until they fail. The manufacturers are only required to disclose how many cycles the wheelchair completed without failure. During fatigue testing the entire wheelchair (frame, seat upholstery, wheels, and all other components) is subjected to a large number of stresses. The composition and construction of each of these components affects the durability of the wheelchair. When a major component of the chair fails, the testing is terminated. If a bolt comes loose or an adjustment needs to be tightened, the testing is continued until a major component failure occurs. Frame Material While many components can be replaced for a small fraction of the cost of the wheelchair, the frame cannot, because of the cost of frame construction. Wheelchair frames are usually made from mild steel, stainless steel, chromoly steel, aluminum, titanium, or a composite. A wheelchair constructed from one type of material is not necessarily more durable than one constructed from another. Although each material has a specific amount of strength per weight of material (strength- to- weight ratio), wheelchair designs vary so much that you cannot determine the durability of the product solely by the material used. The frame tubing thickness, tubing shape, welding technique, and how the components are assembled together are just a few of the factors affecting the fatigue strength of the chair. While the type of frame material may not indicate how long the chair will last, it does provide some other helpful information. FRAME MATERIAL ADVANTAGES DISADVANTAGES Mild steel -Easily repaired and welded -Relatively heavy in places where hightechnology welding equipment is not available Moderate strength- to- weight ratio Stainless steel -Highly resistant to corrosion -Lower strength- to- weight ratio than other steels Chromoly steel -High strength- to- weight ratio -More expensive than mild steels -Essentially a high- technology steel Aluminum -High strength- to- weight ratio -More expensive than mild steels Titanium -Very high strength- to- weight ratio -Very expensive -Highly corrosion resistant Composite -High strength- to- weight ratio -Surface finish chips easily -Ability to form nonconventional shapes Frame Finish The way the frame of the chair is chemically prepared, primed, and painted will affect the durability of the finish. Getting paint to adhere to stainless steel is difficult, and it is almost impossible for titanium. Composite materials are covered with colored gel coat or painted, but these finishes can chip. Steel and aluminum can be finished with various standard processes. One of the best processes is powder coating. This finishing process minimizes paint waste and results in a durable finish. Casters Both the size and the type of caster affect the durability of the wheelchair. During the double drum test, the slats on the cylindrical drum constantly hit the casters, and the forces generated are transferred to the rest of the chair. This is similar to what occurs when you ride over obstacles or uneven terrain (e. g., door thresholds, sidewalk cracks). Because the casters are the first part of the wheelchair that contacts the obstacles and because of their small diameter, they take a substantial beating. Large pneumatic casters can absorb these forces better than small solid casters and can cushion the wheelchair, causing less wear and tear on other wheelchair components. You want to know that your chair will hold up to the sort of use it sees from day to day 26 A Guide to Wheelchair Selection MANEUVERABILITY How much space does the wheelchair need to turn around? You have probably created a home or office environment that allows you as much access as possible in your current wheelchair. Try to make sure your new wheelchair does not create new architectural barriers because its turning radius is larger than that of your current chair. On the other hand, you may want to improve your access so you can maneuver more easily in hotel rooms, small apartments, tight office spaces, narrow dormitory hallways, bathrooms, or those ridiculously small public toilet stalls. Maneuverability Test Procedure ANSI/ RESNA Wheelchair Standard Part 05: Determination of OverallDimensions, Mass, and Turning Space In order to measure turning space, an adjustable corridor is created and a three- point turn maneuver is performed. The corridor is narrowed until the wheelchair is unable to perform the maneuver. The minimum corridor width in which the chair can turn is disclosed. Disclosure Format (as reported by manufacturers) Name of Test Test Result Minimum turnaround width ___ inches (___ mm) Additional information not required for disclosure in the product literature: Minimum turning radius ___ inches (___ mm) Interpretation of Results- Maneuverability The results of this test are essential if you live or work in an environment with tight spaces. If there is a particularly narrow hall or space at home, work, or school, measure its width and search for chairs that can perform a threepoint turn in spaces that size or smaller. Remember that footrest assemblies can be removed, if necessary, to improve the chair's ability to turn around in tight places. The size of the caster can also increase or decrease the wheelchair's maneuverability. Smaller caster wheels swivel more easily without hitting your feet. Once you have limited your choice to a few chairs, you may want to check the turnaround space for each of the chairs to make sure they will be able to get you through or into and out of any tight spots in your home. An extra inch can mean a lot in a small bathroom NOTE: (c) 1994 by the Paralyzed Veterans of America. All rights reserved.