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Medical Diagnostic Equipment Accessibility Standards

Sub-Committee Recommendations

Weight Scales - Final Report

May 31, 2013

The Subcommittee’s technical recommendations for the weight scales have taken into 

consideration the following technical criteria proposed in Chapter 3, part 1195 to Title 36 of the 

Code of Federal Regulations. Specifically, section M303, patient positions equipment designed 

to support seated in a wheelchair.

Abbreviated Chart from Proposed Accessibility Standards for Medical Diagnostics Equipment 

Appendix to part 1195, Section M303.

Patient Positions 

Equipment Designed to 

Support 

Equipment Features 

Addressed in 

Technical Criteria

Types Of Equipment To Which Technical 

Criteria Applies

Seated in a wheelchair 

(M303) 

Wheelchair space, 

including orientation, 

width, depth, knee and 

toe clearance, and 

surface slope

Changes in level at 

entry to wheelchair 

space, including ramps

Components capable of 

examining body parts of 

patients seated in a 

wheelchair, including 

height of breast 

platforms 

Imaging equipment designed for wheelchair 

use

Weight scales designed for wheelchair use 

Both seated in a 

wheelchair (M303) and in 

a standing position 

(M304)

Standing supports Weight scales designed for both patients 

using wheelchairs and those standing

Equipment Evaluated: Wheelchair weight scales with single ramps, dual ramps, stand-on 

scales and stow-a-weigh scales.
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Types of Scales

Single Ramp Scale

(Diagram provided by US Access Board)

Dual Ramp Scale

(Picture provided by Scale –Tronix)

Portable Scales

(Picture provided by Scale -Tronix)

Wall Mounted or “Stow-A-Weigh”

(Picture provided by Scale – Tronix)
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Sub-Committee Summary of Scope for Recommendations

Though sometimes avoided, all patients should have their weight taken as it is a basic 

screening measurement. It is sometimes difficult to take the weight of patients who have 

mobility or stability issues or for those who use wheeled mobility devices. However, without an 

accurate and current weight measurement, chances of missing diagnosis or incorrectly 

prescribing medications increase.

The goal of the sub-committee is to encompass the broadest range of individuals with mobility 

disabilities including wheeled mobility device users in the following recommendations. All 

standard size manual wheelchairs, powered wheelchairs, small to mid-range scooters and most 

bariatric size, extra wide manual chairs can be accommodated as it relates to the platform size

recommendations; however, some of the larger roadside scooter models, typically a 4-wheeled 

base scooter, may not be accommodate by this platform size.

Rationale for including scooters in equipment evaluation: Scooter use is increasing as 

aging ‘Baby Boomers’ acquire mobility disabilities, etc. In 1994-95, 0.21% of elderly (65+) 

adults used scooters (64,000 people), according to our analysis of the NHIS-D published in 

2000 in "Mobility Device Use in the United States." In 2011, 2.3% of elderly population 

65+adults use scooters (about 800,000 people), according to data from the National Health and 

Aging Trends Study. Trend is more than 10 times as many people in 16 years use scooters.

Compare that to wheelchair usage among the 65+ elderly: 2.9% (900,000 people) in 1994-95, 

and 6.1% (2.1 million) in 2011. Double the usage.

Percentage of Scooter Users:

(Chart from NHIS-D published in 2000 in “Mobility devices Use in the United Sates”)

Users 65+ Scooter Wheelchair

Year % / People % / People

1994-95 1 0.21% (64,000) 2.90% (900,000)

2011 2 2.30% (800,000) 6.10% (2.1 million) 

16 year growth 10 times Doubled

1 NHIS-D published in 2000 in "Mobility 

Device Use in the United States" 

2 National Health and Aging Trends Study

It is also acknowledged that not all scooter users can easily transfer from their scooters; 

transfers for scooter users may be just as difficult as those who are wheelchair users. Having 

an accessible weigh scale that can accommodate a wide range of patient populations and 

mobility devices is optimal as it saves the patient from having to transfer just to have their 

weight taken. 
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Rationale for including alternative equipment for taking weight: The Sub-committee 

acknowledges alternative types of equipment that have integrated scales to be an effective 

means of taking a patients weight. Alternative equipment with integrated scales can eliminate

the need for unnecessary patient transfers to a weight scale just to capture a patient’s weight. 

For example, if a patient transfers onto an examination table that has an integrated scale, the 

healthcare provider can also capture the patient’s weight once the patient has made this single 

transfer. Such types of equipment with integrated scales may include; examination tables, 

stretchers, portable lifts and overhead ceiling lifts. The medical diagnostic equipment 

accessibility standards also apply to the alternative equipment for taking weight for each 

function if they include an integrated scale for the patient position it supports; prone, sitting, 

standing, seated in a wheelchair.

Proposed Recommendations and Sub-Committee Recommendations

M303.2.3 Wheelchair Spaces / Depth of Wheelchair Spaces for front or Rear Entry

 Sub-Committee Recommendation: The Sub-committee and Full Committee have

decided not to act on the proposed recommendation by the Notice of Proposed 

Rulemaking (NPRM) and retain the proposed provision as is. Based on recent 

anthropometric data, NPRM proposes to increase minimum depth dimension from 48 to 

58 inches – majority of members have no opinion or anticipation of a situation where 

requirement is needed.

Exceptions Considered for Wheelchair Spaces on Raised Platforms

M303.2.2 Proposed Exception: The exception to the minimum width in M303.2.2 would 

apply where ramped surfaces are provided on the opposite sides of the raised platform so that 

patients using wheelchairs can enter and exit the platform facing the same direction. The 

exception would permit the width of the wheelchair space between the edge protection to be 

reduced to 32 inches wide minimum at the platform level. This dimension is based on 

provisions in the 2004 ADA and ABA Accessibility Guidelines that allow accessible routes, 

which normally must be 36 inches wide minimum, to be 32 inches wide minimum for short 

distances such as at door openings. The exception would require a space 36 inches wide 

minimum to be provided outside the perimeter of the raised platform and above any edge 

protection so that patients using a manual wheelchair can extend their arms and elbows when 

they push on the wheel rims to maneuver onto and off of the platforms.

M303.2.3 Proposed Exception: The exception to the minimum depth in M303.2.3 for 

wheelchair spaces entered from the front or rear would permit a portion of the 48 inch

minimum depth of the wheelchair space that accommodates the wheelchair footrests to extend 

beyond the raised platform and over any edge protection. For example, the wheelchair 

footrests would be allowed to extend beyond the depth of the raised platform and over any edge 

protection on wheelchair weight scales used by patients seated in a wheelchair.
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 Sub-Committee Recommendation: Platform size shall be clear width of 32 inches

minimum and clear length of 40 inches minimum.

(Figure 1 –Clear Platform showing the measurements of 32” wide x 40” inches length

Rationale: Clear platform size of 32 inches minimum width x 40 inches minimum length

accommodates non-powered and powered wheeled mobility devices including scooters; small 

and mid-size scooters. May not accommodate some larger roadside scooters with 4-wheeled 

based. This platform dimension is consistent with the recommendations of the IDeA Center 

Study recommendations for a minimum flat surface of 40 inches length for platforms 

accommodating wheeled mobility devices including scooters. This size platform allows for 

maneuverability on the platform for positioning and takes into consideration the operations of 

the wheelchair / scooter user to not always have the ability to stop precisely in the middle of the 

platform.

To have an accurate weight the wheelbase* 4 wheels and 3 wheels for some scooters must be 

on the platform (and make contact). The foot pedals, footrests, scooter deck and tip wheels 

can overhang or extend beyond the platform and still get an accurate weight. 

*The IDeA Center Study defines wheelchair wheelbase as the distance from the center 

of the primary drive wheel to the center of the caster measured parallel to the floor.

*The IDeA Center Study defines scooter wheelbase as the distance from the center of 

the primary drive wheels to the center of the back or front wheels measured parallel to 

the floor. 

*The IDeA Center Study findings indicate that a 36 inch length accommodates standard 

manual and motorized wheelchairs and most, if not all, bariatric size- extra wide manual 

chairs 

IDeA Center Study at the University of Buffalo, New York): Summary analysis of 

wheelbase measurements on wheeled mobility devices
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IDeA Center (Buffalo Study) Recommendations for Platform Length:

 a minimum flat surface of 40 in. length for platforms accommodating wheeled mobility 

devices including scooters

 a minimum flat surface of 33 in. length for platforms accommodating wheeled mobility 

devices excluding scooters
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Ramps M303:3.3, 3.3.1, 3.3.2

M303.3 Proposed Provision: Changes in Level at Entry to Wheelchair Spaces 

includes technical criteria for changes in level at the entry to a wheelchair space as may occur 

at wheelchair weight scales with raised platforms. The technical criteria are consistent with the 

2004 ADA and ABA Accessibility Guidelines. Level changes up to 1⁄4 inch high are permitted to 

be vertical. Level changes between 1⁄4 inch high and 1⁄2 inch high would be required to be 

beveled with a slope not steeper than 1:2. Level changes greater than 1⁄2 inch high would be 

required to be ramped. Ramp runs would be required to have a running slope not steeper than 

1:12 and a cross slope not steeper than 1:48. The clear width of ramp runs would be required 

to be 36 inches minimum. Ramps with drop offs 1⁄2 inch or greater would be required to provide 

edge protection 2 inches high minimum on each side to prevent users from inadvertently 

travelling off the sides of the ramped surface. 

 Sub-Committee Recommendation: Steepest Slope permitted to be: 

 Rise 0 to 1 1⁄2 inches – 1:2 Slope

 Rise >1 1⁄2 to 2 1⁄2 inches – 1:8* Slope 

 Rise >2 1⁄2 inches – 1:12 Slope

Rationale: Based on Weight Scales Subcommittee recommendation with full Committee’s 

input and partly the 2004 ADA and ABA Accessibility Guidelines. *The rise of >1 1⁄2 to 2 1⁄2 

inches - 1:8 slope is from section 405.2 Maximum Ramp Slope and Rise for Existing Sites, 

Buildings, and Facilities - [A steeper ramp for a limited rise is allowable]. 

A ramp, using a 1:2 slope, will allow for short rise ramps found on stow-a-weigh scales. Space 

constraints are of consideration in this recommendation, as medical equipment and adequate 

space in the acute care or in the medical office setting are often competing. Scales that can be 

wall mounted or that are portable would facilitate where there are space constraints. Patients 

are always supervised and assisted by a healthcare provider when taking weight. 

Current weight cell load technology that exists, allows for a low platform profile between 3⁄4” to 

11⁄2”. As the height of the platform decreases, the length of the ramp can also decrease. The 

trend for the industry is towards lower weight cell technology development; however, this 

existing low weight cell profile may represent the limits of technology.

 Sub-Committee Recommendation: Edge Protection

o Single ramp scales: 2 inch edge protection absolute is required opposite the 

entry ramp on the platform as a safety feature to prevent wheeled mobility device 

drivers from over-shooting the platform as not all devices stop immediately when 

braking. 

o A 2 inch maximum height is recommended so the edge protection does not 

obstruct the footrest from hanging over.

o Edge protection is required for either side of the platform (front edge and rear 

edge) and ramp. This is an additional safety recommendation.

 Single and dual ramp scales: 2 inches minimum required on both sides

(front edge and rear edge) of platform
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 Single and dual ramp scales: 2 inches minimum required on both sides 

of entry ramps

 Not required where platform is ≤ 11⁄2 inches 

Rationale: Edge protection provides additional safety features so user of wheeled mobility 

devices do not inadvertently drivel off ramp and/or platform.
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Single Ramp Scale with 2” Edge Protection

Opposite the ramp entry and on both sides of the platform and ramp

Figure 2: Picture of single ramp scale showing the 2” edge protection at the opposite side of 

the platform and showing the 2” minimum edge protection on both sides of the ramp and 

platform

Dual Ramp Scale with 2” Edge Protection

On both sides of the platform and ramp

Figure 3: Picture of a dual ramp scale showing the edge protection on both sides of the 

platform and ramp
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Standing Supports (M304.3 and M305.3)

M304.3 Proposed Provision: Would require standing supports to be provided on each side of 

the standing surface on diagnostic equipment used by patients in a standing position. M305.3 

would require the standing supports to provide continuous support throughout the use of the 

diagnostic equipment and to not rotate within their fittings. 

M305.3 Proposed Provision: Also provides technical criteria for standing supports in 

horizontal and vertical positions. Standing supports can be provided in a horizontal position, 

vertical position, or a combination of horizontal and vertical positions, as long as the minimum 

length of gripping surface is provided for the support position used on each side of the standing 

surface. Standing supports that adjust from horizontal to vertical positions and at angles in 

between, such as a bar that folds up and locks into multiple positions, can be used. These 

kinds of adjustable supports are not required but would accommodate a broad range of patients 

with disabilities, particularly where a patient needs to assume multiple body positions for a 

diagnostic procedure or needs to step up onto a surface and then maintain balance afterwards. 

 Sub-Committee Recommendation: Standing Supports – Location

 (scales serving both wheelchair and standing users).

o 1 side of platform for dual ramp entry of platform

o 2 sides of platform for single ramp entry with 34” minimum width between 

standing supports 

o The standing supports need to be tied in to the weighing platform for weight 

accuracy. 

Rationale: Standing supports required on one side of dual ramp has relevance for users 

being able to access either side for entry – user may only have one usable side due to condition 

such as a stroke, or right or left side paralysis or weakness etc. 

Standing supports required on both sides for single ramp entry to assist user to gain access to 

weight platform. 

A 34” minimum width between the supports allows for adequate elbow space to push wheels 

onto platform and does not infringe on the 32” platform. 

Standing Supports (scales serving both wheelchair and standing users)

 Sub-Committee Recommendation: Standing Supports - Length

The length of the standing supports to be 32” minimum for single ramp scale and 40” 

minimum for dual ramp scale.

o Single Entry Ramp - On both sides of single entry platform for a length of 32 

inches minimum starting at platform entry edge. 

o Dual Entry Ramp – On one side of dual entry platform for a length of 40 

inches minimum.
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Rationale: Having standing supports for 80%, or 32 inches minimum length at the platform

entry edge on the single entry ramp allows for enough coverage in length to assist the patient 

for stability to grab on both sides, to gain access to the platform for this one way entry and exit. 

Standing supports on the dual entry ramp, allows for the full length of the platform to have a

standing support available on one side for the patient to provide stability when entering onto the 

platform and exiting off the platform - a user may select which side of the platform to enter 

given the limitation of having one strong side due to conditions such as stroke or right or left 

side paralysis or weakness etc. 

Standing Supports - Single Ramp Scale

Figure 4: picture of standing supports on both sides of a single entry ramp scale showing the 

80% coverage (or 32” length) starting at the platform edge and the 34” minimum space between 

supports

Standing supports – Dual Ramp Scale

Figure 5: picture of standing supports on one side of a dual ramp scale of the platform length 

of 40” minimum

References: 

NHIS-D published in 2000 in "Mobility Device Use in the United States."

IDeA Center (Buffalo Study) wheelbase measurements on wheeled mobility devices