External Roof Top

Data centres often have extensive exterior roof areas with large plant items such as diesel-powered generators, fuel storage and air conditioners. Linking these items may involve additional pipework, ducts, and cable trays. As a result, navigation can be difficult.

These areas require lighting for staff to find their way safely. It provides security, prevents theft or vandalism, and enables maintenance and fault rectification. Bulky items cast shadows, making a general floodlighting scheme impractical and challenging the designer. The best approach is to use strategically placed localised lighting, which can be wall-mounted or installed on the support structure.

Illumination Levels

There is no specific guidance for external plant areas in the CIBSE: SLL Lighting Guides, but there are correlating applications.

Extract from CIBSE: SLL Lighting Guide 1 - Industrial Environment 2018

Application	Maintained illuminance (lux)
Section 4.5 Security Lighting
Medium Risk Areas	20 lux minimum maintained illuminance, uniformity 0.4 (min/average)
High Risk Areas	50 lux minimum maintained illuminance, uniformity 0.4 (min/average)

In areas where close work is needed, an illumination level as high as 200 lux may be needed. This is often achieved using local task lighting.

Choice of Luminaire

The Mercian is ideal because it offers excellent vertical illumination for locations with lower mounting heights.

The A-Line and Thoroproof can be mounted on the support infrastructure to provide higher illumination levels where needed. Both have external fixing options, so can be installed easily without compromising the IP rating.