We have made an update to our guide on Lighting regulations and guidelines, please see our new article on this subject here 


There are a number of regulations for new and existing buildings to achieve high energy efficiency projects. With our wide range of high efficiency luminaires energy and maintenance costs can be reduced. It is essential that designers and clients are aware of the regulation requirements in order to maximise efficiency.

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The LG7 is issued by the Society of Light & Lighting and is intended to be a guide for designers of lighting for offices. The aim of the guidance is to achieve a fully compliant lighting design, requiring a good luminance balance between the task area, walls and ceiling. Illuminance ratio should be at least 50% for the task area, 30% for the ceiling and 20% for the floor.

Different luminaires, be it direct or indirect, natural or artificial can affect the different lighting values of each surface. Different types of surfaces can have various reflectivity values, such as an matt emulsion painted wall or a gloss painted wall.

Colours also have an effect on this and can be accessed using a surface reflectance and colour sample chart from CIBSE. We are able to work this out as part of our free lighting design service here at 299.


LENI stands for Lighting Energy Numeric Indicator, it promotes efficient use of lighting, not just efficiency of individual lighting components. It consists of three complex control factors, Occupancy Factor (automatically controlling the system by detecting the presence of people in a room), Factor for daylight (lighting dims in response to daylight being available), Constant Illuminance Factor (where constant illuminance system is implemented).

BS EN 12464

EN-12464-1 refers to ‘The Lighting of Workplaces’, a standard about the quality aspects of lighting workstations and their direct environment. Workstations are defined as a work area, with task lighting then there will be basic lighting in the rest of the area. Luminance control is also specified so there are no reflections on computer screens.

Part L

Part L is a new method for measuring lighting efficiency, taking into account the efficiency of the whole lighting installation, not just the components. As of 2013, the new minimum performance required is 60 Luminaire lumens per circuit watt (total lumen output divided by wattage consumption).

If the luminaire has controls then the regulations permit the efficacy to be a minimum of 42 LL/cct watt.
Other design requirements include adequate illumination of each work task area, unified glare rating, contrasts between task zones and brightness between walls and ceilings.

These recommendations are referenced in the EN12464-1 guidance for a safe and healthy working environment.


Our team of project engineers at 299 Lighting have the ability to calculate if your project is compliant with relevant regulations. Get in contact with us today if you need any help achieving an energy efficient building on 0203 7737530



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