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.