A clearer vision on Part M for electrical services

Legrand
A significant difference in reflectance between electrical accessories and the adjacent wall helps the visually impaired locate them in unfamiliar surroundings.
Stephen Willmore explores the implications of Part M of the Building Regulations on electrical installations and how to meet their requirements.Nearly four years have passed since the 2004 edition of Approved Document M (access to and use of buildings) of the Building Regulations (2000) was published. However, because of the time lag between its introduction and impact on the industry there is still some confusion over what exactly it entails. As with most new regulations, Part M was unveiled with the usual fanfare and greeted with the expected industry-changing reverence. Although the building-services industry was well aware it would not have an immediate impact because it would only be relevant to applications for Building Regulation approval submitted on, or after, 1 May 2004. As we all know, the time between submitting an application and starting construction work can often be measured in years, rather than months. Time lag The result of this time lag was twofold. From a manufacturer’s point of view, it provided the time to digest the regulations and draw their own conclusions as to what they meant to their product development strategy. Whereas, those who were not immediately affected could simply be forget about it until it became relevant. What this has led to is today’s situation where, despite four years having passed and Part M being part and parcel of virtually every new project coming on line, there is still some confusion surrounding it. As a great deal of Part M is open to interpretation, it is easy to see why this is the case. Take for example Section 4.28. Controls that contrast visually with their surroundings are more convenient for visually impaired people, as are light switches that are activated by a large push pad. The colours red and green should not be used in combination as indicators of ‘on’ and ‘off’ for switches and controls. It may be useful to use text or a pictogram to clarify the purpose and status of multiple switches and controls. Let us consider only the section referring to the contrast of controls with their surroundings, which is aimed at assisting the visually impaired locate controls in unfamiliar environments. The contrast is considered acceptable when there is a difference of 30 points in light reflectance value between the controls and their surroundings. What this means is that there are many combinations of colour and finish that will satisfy this recommendation. However, it should be recognised that very different colours do not necessarily provide contrast. Let us imagine a mid-range red switch plate sits on a mid-range blue wall. To a person with normal vision the switch plate would be easily seen. However, to some visually impaired people this combination of switch and wall colours may look like a monochrome photograph, with a mid-range grey switch plate sitting on a mid range grey wall, and they would struggle to see it despite the distinctly different colours. It also needs to be noted that for a wall light switch, Part M is not looking for a contrast of the switch with its plate, but a contrast between the switch plate and the surrounding wall. The spacing of switches when more than one is used is on the same panel is another subject referred to within the guidelines, but without the provision of a definitive solution. Specifiers, architects and contractors are being forced to set their own, potentially differing, standards to which the manufacturer needs to try to adhere in order to be considered for specification. Emphasis This uncertainty means that the emphasis is very much on the manufacturer to provide products that enable specifiers to meet the requirements. Manufacturers also need to offer a standard of design and functionality that makes them stand out in a competitive market place. Take for example, wall-mounted socket-outlets and switches. They now have to be installed 450 to 1200 mm above the floor in dwellings, and 400 to 1400 mm in buildings other than dwellings. As such, they are far more visible than ever before, meaning aesthetic appeal now plays an even bigger role in a product’s success — which has led to everything from switches and socket-outlets to trunking systems and consumer units undergoing a Part M makeover. On a positive note, the non-prescriptive nature of Part M has given manufacturers significant freedom in product design — a position that will enable the market to evolve naturally as different manufacturers continue to research and develop products in the way they see fit rather than being heavily constrained by prescriptive regulatory requirements. Such natural evolution is likely to lead to a convergence of views on what is and is not appropriate, eventually leading to optimum solutions. In the meantime, the best way to aim for compliance is to refer to a Part M guide. We recently published such a document, which features a brief overview of the regulation’s key points, a Part M contrast guide, 4-point explanation on how to comply using Legrand products and a rundown of all of our Part M compliant products. Legrand designs and makes a broad spectrum of products suitable for use in Part M installations. Stephen Willmore is regulations and standards manager with Legrand.
EXTRA PICTURE

Helpful guidance on complying with Part M is available from manufacturers such as Legrand. For more information, use the link below.

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