PRODUCT DESIGN SPECIFICATION

Product Design Specification

Product Design Specification

Introduction

This paper is based on the topic of product design specification. The product selected for this particular paper is an evacuation device for wheelchair users, who at the time of emergency are in need of urgent help from others, especially from their family members and/or nurses.

Ascending or descending stairs remains the most difficult part of escape travel for people with mobility impairments (Nisbet, 2006). As mentioned elsewhere, the use of passenger lifts for emergency evacuation is not advised due to the potential for people to be trapped if the power supply is interrupted and the dangers of the lift being opened inadvertently on the fire floor with the potential to expose occupants to danger (Kensing 2007). In buildings not equipped with evacuation lifts, the normal approach is for those requiring assistance with mobility to move or be moved to safe areas, where they are protected from the fire, to await the assistance of trained staff (Jaffe, 2005). Where wheelchair users need to be evacuated up or down stairs, it is not considered safe to evacuate them in their own chairs as this poses unacceptable risks to those providing assistance as well as the person in the chair (Espinosa, 2006).

Commercially available evacuation chairs can be used to evacuate people downwards in a controlled manner (Cooper, 2006). The chairs are designed to fold into a compact size for storage within protected escape stairs. Suppliers of the chairs provide training on their operation, which needs to be given to a sufficient number of people to ensure adequate levels of trained personnel are available at all material times. The person requiring assisted escape must first transfer to the evacuation chair and may require assistance (Beynon, 2008). The descent of the chair is under the force of gravity and chairs are fitted with a braking system that allows the rate of descent to be controlled by a single person. Evacuation chairs are not designed for upwards escape, such as would be the case for basements (Nisbet, 2006).

Other devices are available that can ascend or descend stairs using a battery powered motor. These can be divided into devices which require no attachments to be fitted to wheelchairs in advance and those which do (Kensing 2007). The former devices involve a tracked platform or support frame onto which a user's wheelchair is strapped. A battery powered motor enables the platform to ascend or descend stairs with minimal effort on the part of the assistant. Other stair climbing devices require a bracket to be fitted to the wheelchair to be evacuated, onto which the device is attached when needed (Jaffe, 2005). This means that stair climbing devices are generally only suitable for evacuation of staff members or others whose presence in the building can be anticipated, and to whose chairs the necessary brackets have been pre-fitted. It might be possible to make stair climbers of more general use by fitting brackets to a spare conventional wheelchair which is stored at the vertical escape ...