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Test methods are under development to assess furniture designed for overweight people, for everyday and medical uses.
Several million people in the UK are considered to be clinically obese. With childhood obesity levels also rising, the needs of heavier people, as well as those who have to care for some of them, have to be addressed.
Generally, people weighing more than 114kg (250lbs), or with a Body Mass Index (BMI) of 38 or greater are defined as obese. BMI is the ratio between weight and height and is calculated by dividing the weight by the height squared.
A number of furniture suppliers, both in the UK, and particularly in the US, supply various types of seating for bariatric use (bariatrics is the field of medicine concerned with obesity). They can be manufactured in a variety of designs and styles, including electrical recliners (motion furniture), some of which are also designed to be slept on, riser chairs (or a combination of riser and recliner), fireside chairs, office pedestal chairs and specialist versions for medical care purposes.
Of course, all such designs need to be larger and more robust than standard items, with stronger and wider frames, including arms which can support the occupants raising or lowering themselves. In some cases chairs will provide individual seating widths of up to 76cm (30in) and accommodate weights of up to 341kg (750lbs). These factors alone can increase the price significantly above that charged for an average chair. It is therefore important to ensure that these designs are fit for purpose before committing to production or purchase. They need to be safe, durable, comfortable, easy to use and maintain, and suitable for the intended environment. They also need to comply with any relevant legislation and to be easily installable within the space available.
SATRA already provides a comprehensive chair testing service that can be applied to most seating designs. However, for bariatric or heavy-duty use, the current UK and European test standards have no provision for the extra loads and forces that may be required. So far, with office pedestal chairs, SATRA has developed a test method which incorporates the clauses of BS 5459-2, but with loads and cycles for persons weighing up to 225kg (see table 1).
|Table 1: Performance comparison example|
|Standard/Clause No||Test||Persons up to 150kg||Persons up to 225kg|
|BS 5459-2 A.5.1||Fore and aft safety|
|Seat load V1||1,400N||2,100N|
|Back load H1||400N||600N|
|Maximum number of cycles||500,000||500,000|
|BS 5459-2 A.5.5||Side to side safety|
|Downward vertical force||1,200N||1,800N|
|Maximum number of cycles||250,000||250,000|
|BS 5459-2 – Specification for performance requirements and tests for office furniture (office pedestal seating for use by persons weighing up to 150kg and for use up to 24 hours a day, including type-approval tests for individual components).|
For standard chairs, such as sofa style and dining, the test methods from EN 1728 are used but with a safety factor multiplication of x1.5. For example, where the requirement is 30 stone (190.5kg/ 420lbs), the safety factor increases the load to 45 stone (286kg/630lbs). Suppliers and purchasers can also provide their own test protocol, to ensure that specific products can perform to their own criteria.
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