ISO 7176-21:2003

Wheelchairs — Part 21: Requirements and test methods for electromagnetic compatibility of electrically powered wheelchairs and motorized scooters

ISO 7176-21:2003 specifies requirements and test methods for electromagnetic emissions and for electromagnetic immunity of electrically powered wheelchairs and motorized scooters with a maximum speed of not more than 15 km/h for indoor and outdoor use by people with disabilities. It is also applicable to manual wheelchairs with an add-on power kit. It is not applicable to vehicles designed to carry more than one person. ISO 7176-21:2003 also specifies additional requirements for electromagnetic emissions and for electromagnetic immunity of electrically powered wheelchairs and motorized scooters with a built-in battery charger. It is not applicable to battery chargers that are not built into a wheelchair. A reference configuration is specified for adjustable wheelchairs and scooters to enable test results to be used for comparison of performance.

Fauteuils roulants — Partie 21: Exigences et méthodes d'essai pour la compatibilité des fauteuils roulants électriques et scooters motorisés

General Information

• Status: Withdrawn
• Publication Date: 29-Apr-2003
• Withdrawal Date: 29-Apr-2003
• ICS: 11.180.10 - Aids and adaptation for moving
• ICS: 33.100.01 - Electromagnetic compatibility in general
• Technical Committee: ISO/TC 173/SC 1 - Wheelchairs
• Drafting Committee: ISO/TC 173/SC 1/WG 10 - Requirements and test methods for electro-technical systems for wheelchairs
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 16-Mar-2009

Relations

• Revised: ISO 7176-21:2009 - Wheelchairs — Part 21: Requirements and test methods for electromagnetic compatibility of electrically powered wheelchairs and scooters, and battery chargers
• Effective Date: 15-Apr-2008

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 7176-21
First edition
2003-04-15


Wheelchairs —
Part 21:
Requirements and test methods for
electromagnetic compatibility of
electrically powered wheelchairs and
motorized scooters
Fauteuils roulants —
Partie 21: Exigences et méthodes d'essai pour la compatibilité des
fauteuils roulants électriques et scooters motorisés




Reference number
ISO 7176-21:2003(E)
©
ISO 2003

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ISO 7176-21:2003(E)
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ii © ISO 2003 — All rights reserved

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ISO 7176-21:2003(E)
Contents Page
Foreword. iv
Introduction . vi
1 Scope. 1
2 Normative references . 1
3 Terms and definitions. 2
4 Classification of electrically powered wheelchairs . 4
5 Requirements . 4
5.1 General. 4
5.2 Driving. 4
5.3 Charging . 5
6 Test apparatus. 7
7 Preparation of test wheelchair. 8
7.1 Equipping the wheelchair. 8
7.2 Supporting the wheelchair. 8
7.3 Adjustments . 8
7.4 Settings for driving tests. 9
7.5 Settings for charging tests. 9
8 Sequence of tests . 9
9 Test methods for electromagnetic emissions . 9
9.1 Radiated emissions test. 9
9.2 Conducted emissions test . 9
10 Test methods for electromagnetic immunity . 9
10.1 Electrostatic discharge immunity test. 9
10.2 Charged-frame electrostatic discharge immunity test. 10
10.3 Radiated immunity test. 11
10.4 Fast transient/burst immunity test . 12
10.5 Surge immunity test. 12
10.6 Conducted radio-frequency immunity test. 12
10.7 Voltage dips test . 12
10.8 Short interruptions test . 14
11 Wheel speed change calculation. 14
12 Test report . 15
13 Disclosure. 15

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ISO 7176-21:2003(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 7176-21 was prepared by Technical Committee ISO/TC 173, Technical systems and aids for disabled or
handicapped persons, Subcommittee SC 1, Wheelchairs.
ISO 7176 consists of the following parts, under the general title Wheelchairs:
 Part 21: Requirements and test methods for electromagnetic compatibility of electrically powered
 Part 1: Determination of static stability
 Part 2: Determination of dynamic stability of electric wheelchairs
 Part 3: Determination of effectiveness of brakes
 Part 4: Energy consumption of electric wheelchairs and scooters for determination of theoretical distance
range
 Part 5: Determination of overall dimensions, mass and turning space
 Part 6: Determination of maximum speed, acceleration and deceleration of electric wheelchairs
 Part 7: Measurement of seating and wheel dimensions
 Part 8: Requirements and test methods for static, impact and fatigue strengths
 Part 9: Climatic tests for electric wheelchairs
 Part 10: Determination of obstacle-climbing ability of electric wheelchairs
 Part 11: Test dummies
 Part 13: Determination of coefficient of friction of test surfaces
 Part 14: Power and control systems for electric wheelchairs — Requirements and test methods
 Part 15: Requirements for information disclosure, documentation and labelling
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ISO 7176-21:2003(E)
 Part 16: Resistance to ignition of upholstered parts — Requirements and test methods
 Part 19: Wheeled mobility devices for use in motor vehicles
 Part 21: Requirements and test methods for electromagnetic compatibility of electrically powered
wheelchairs and motorized scooters
 Part 22: Set-up procedures
 Part 23: Requirements and test methods for attendant-operated stair-climbing devices
The following parts are also on the programme of work
 Part 20: Determination of the performance of stand-up type wheelchairs
 Part 24: User-operated stair-climbing devices — Requirements and test methods
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ISO 7176-21:2003(E)
Introduction
Electrically powered wheelchairs should operate without introducing significant electromagnetic disturbances
to the environment and without significant degradation of operational performance in the presence of
electromagnetic disturbances that can be expected in normal use. Wheelchairs can be expected to operate in
traffic areas and therefore should be immune to radio frequency fields from fixed and mobile communications
equipment, as well as from other sources of electromagnetic disturbance. Injury could occur in the event of
unintentional movement or change in direction of a wheelchair.
This part of ISO 7176 specifies requirements and test methods for wheelchairs to minimize the risks
connected with reasonably foreseeable electromagnetic interference and electrostatic discharge and to
minimize the risk of producing electromagnetic fields which could impair the operation of other devices or
equipment in the wheelchair's usual environment.
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INTERNATIONAL STANDARD ISO 7176-21:2003(E)

Wheelchairs —
Part 21:
Requirements and test methods for electromagnetic
compatibility of electrically powered wheelchairs and motorized
scooters
WARNING — This part of ISO 7176 calls for the use of procedures that may be injurious to health if
adequate precautions are not taken. It refers only to technical suitability and does not absolve the
manufacturer or test house from legal obligations relating to health and safety at any stage.
1 Scope
This part of ISO 7176 specifies requirements and test methods for electromagnetic emissions and for
electromagnetic immunity of electrically powered wheelchairs and motorized scooters with a maximum speed
of not more than 15 km/h for indoor and outdoor use by people with disabilities. It is also applicable to manual
wheelchairs with an add-on power kit. It is not applicable to vehicles designed to carry more than one person.
This part of ISO 7176 also specifies additional requirements for electromagnetic emissions and for
electromagnetic immunity of electrically powered wheelchairs and motorized scooters with a built-in battery
charger. It is not applicable to battery chargers that are not built into a wheelchair.
A reference configuration is specified for adjustable wheelchairs and scooters to enable test results to be used
for comparison of performance.
NOTE The term “wheelchair” is used in this part of ISO 7176 to cover electrically powered wheelchairs, motorized
scooters and manual wheelchairs with an add-on power kit.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 7176-5, Wheelchairs — Part 5: Determination of overall dimensions, mass and turning space
ISO 7176-9, Wheelchairs — Part 9: Climatic tests for electric wheelchairs
ISO 7176-15, Wheelchairs — Part 15: Requirements for information disclosure, documentation and labelling
ISO 7176-22, Wheelchairs — Part 22: Set-up procedures
IEC 61000-4-2, Electromagnetic compatibility (EMC) — Part 4: Testing and measurement techniques —
Section 2: Electrostatic discharge immunity test
IEC 61000-4-3, Electromagnetic compatibility (EMC) — Part 4: Testing and measurement techniques —
Section 3: Radiated, radio frequency, electromagnetic field immunity test
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ISO 7176-21:2003(E)
IEC 61000-4-4, Electromagnetic compatibility (EMC) — Part 4: Testing and measurement techniques —
Section 4: Electrical fast transient / burst immunity test
IEC 61000-4-5, Electromagnetic compatibility (EMC) — Part 4: Testing and measurement techniques —
Section 5: Surge immunity test
IEC 61000-4-6, Electromagnetic compatibility (EMC) — Part 4: Testing and measurement techniques —
Section 6: Immunity to conducted disturbances, induced by radio frequency fields
IEC 61000-4-11, Electromagnetic compatibility (EMC) — Part 4: Testing and measurement techniques —
Section 11: Voltage dips, short interruptions and voltage variations immunity tests
CISPR 11, Industrial, scientific and medical (ISM) radio frequency equipment — Electromagnetic disturbance
characteristics — Limits and methods of measurement
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
front vertical plane
vertical plane which is normal to the forward direction of travel and tangential to the front edge of the furthest
forward wheel
See Figure 1.
3.2
rear vertical plane
vertical plane which is normal to the forward direction of travel and tangential to the back edge of the rearmost
wheel
See Figure 1.
3.3
side vertical plane
vertical plane which is parallel to the forward direction of travel and tangential to the outer edge of the
outermost wheel on the side of the wheelchair
See Figure 1.
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ISO 7176-21:2003(E)

Key
1 rear vertical
2 front vertical
3 side vertical
Figure 1 — Reference planes
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ISO 7176-21:2003(E)
4 Classification of electrically powered wheelchairs
Electrically powered wheelchairs are classified as follows:
 category A: wheelchairs with electronic differential steering and electronic brake control;
 category B: wheelchairs with electronic speed control, electronic servo steering and electronic brake
control;
 category C: wheelchairs with electronic speed control, manual steering and electronic brake control;
 category D: wheelchairs with electronic differential steering and manual brake control;
 category E: wheelchairs with electronic speed control, electronic servo steering and manual brake control;
 category F: wheelchairs with electronic speed control, manual steering and manual brake control;
 category G: wheelchairs with a simple on-off motor, manual steering and manual brake control.
A wheelchair can fall into more than one category.
5 Requirements
5.1 General
All wheelchairs shall meet the requirements of 5.2.
Wheelchairs with a built-in battery charger shall also meet the requirements of 5.3.
5.2 Driving
NOTE An observation period of 2 s is specified in many of the requirements of 5.2 and 5.3. This is not intended to
imply that it is acceptable for the wheelchair to fail after the observation period has elapsed. An indefinite observation
period is impractical and it is assumed that, if the wheelchair does fail during a test, it will fail within 2 s of a test event.
5.2.1 Radiated emissions
When tested in accordance with 9.1, the wheelchair shall meet the requirements of the group 1, class B
radiated emissions limits specified in CISPR 11.
5.2.2 Electrostatic discharge (ESD) immunity (driving)
Prior to and at the conclusion of testing in accordance with 10.1 and 10.2, the wheelchair shall meet the
functional requirement specified in ISO 7176-9 (see also clause 8 in this part of ISO 7176).
When the wheelchair is tested in accordance with 10.1, using test levels of ± 2 kV, ± 4 kV and ± 6 kV for
contact discharges and test levels of ± 2 kV, ± 4 kV and ± 8 kV for air discharges, and when the wheelchair is
tested in accordance with 10.2 using a test level of ± 8 kV:
a) the drive system of the wheelchair shall meet the requirements of 5.2.4 during each discharge and for 2 s
following each discharge or set of discharges if a programmable ESD generator is used;
b) electrically powered devices which are not used for driving (such as servo-assisted leg supports and
seating systems with stand-up functions) shall not move during each discharge and for 2 s following each
discharge or set of discharges, if a programmable ESD generator is used.
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ISO 7176-21:2003(E)
5.2.3 Radiated immunity
Prior to and at the conclusion of testing in accordance with 10.3, the wheelchair shall meet the functional
requirement specified in ISO 7176-9 (see also clause 8 in this part of ISO 7176).
When the wheelchair is tested in accordance with 10.3, using a test level of 12 V/m, from 26 MHz to 1 GHz:
a) the drive system of the wheelchair shall meet the requirements of 5.2.4 in the presence of the applied
radio frequency (RF) field;
b) electrically powered devices which are not used for driving (such as servo-assisted leg supports and
seating systems with stand-up functions) shall not move in the presence of the applied RF field.
5.2.4 Stability of speed and direction
5.2.4.1 Speed
For category A, B, C, D, E and F wheelchairs, the average wheel speed change, ∆S , calculated as
avg
specified in clause 11, shall not exceed ± 20 %.
NOTE A positive number indicates a speed increase, while a negative number indicates a speed decrease.
For category G wheelchairs, the speed requirement does not apply.
5.2.4.2 Steering
For category A and D wheelchairs (wheelchairs with electronic differential steering), the differential wheel
speed change, ∆S , calculated as specified in clause 11, shall not exceed ± 25 %.
diff
NOTE A positive number corresponds to a right turn, while a negative number corresponds to a left turn.
For category B and E wheelchairs (wheelchairs with electronic servo steering), the maximum permissible
change in steering servo position or steered wheel angle is that corresponding to a turning radius of 4 m, as
specified in ISO 7176-5.
For category C, F and G wheelchairs (wheelchairs with manual steering), the steering requirement does not
apply.
5.3 Charging
5.3.1 Conducted emissions
When tested in accordance with 9.2, the wheelchair shall meet the requirements of the group 1, class B
conducted emissions limits of CISPR 11.
5.3.2 Radiated emissions
When tested in accordance with 9.1, the wheelchair shall meet the requirements of the group 1, class B
radiated emissions limits of CISPR 11.
5.3.3 Electrostatic discharge (ESD) immunity (charging)
Prior to and at the conclusion of testing in accordance with 10.1, the wheelchair shall meet the functional
requirement specified in ISO 7176-9 (see also clause 8 in this part of ISO 7176).
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ISO 7176-21:2003(E)
When the wheelchair is tested in accordance with 10.1, using test levels of ± 2 kV, ± 4 kV and ± 6 kV for
contact discharges and test levels of ± 2 kV, ± 4 kV and ± 8 kV for air discharges, during the discharge and for
2 s following each discharge or set of discharges if a programmable ESD generator is used:
 the driven wheels shall not move,
 the automatic brakes shall not release, and
 the electrically powered devices which are not used for driving (such as servo-assisted leg supports and
seating systems with stand-up functions) shall not move.
At the conclusion of testing in accordance with 10.1, the battery charger shall continue to function without
operator intervention.
5.3.4 Fast transient/burst immunity
Prior to and at the conclusion of testing in accordance with 10.4, the wheelchair shall meet the functional
requirement specified in ISO 7176-9 (see also clause 8 in this part of ISO 7176).
When the wheelchair is tested in accordance with 10.4, using a test level of 1 kV, during the test and for 2 s
following the test:
 the driven wheels shall not move,
 the automatic brakes shall not release, and
 the electrically powered devices which are not used for driving (such as servo-assisted leg supports and
seating systems with stand-up functio
...