Characteristics of Downlights
- Downlights can be used to deliver a lot of light onto horizontal surfaces such as tables and work tops and adjustable types are available to highlight pictures and other items of interest.
- Downlights do not light the ceiling this can create a cosy effect and can save on building costs as the ceiling doesn’t require as much finishing.
- Downlights have to be placed close enough to the walls so as to light them, or use in conjunction with wall lights.
- Downlights depending on their design are subject to where they may be positioned in a ceiling. Not all ceiling cavities are appropriate for downlight installation due to physical constraints, fire safety and or lamp life issues. Also if building insulation is already present this may dictate what type of downlight is allowed to be installed.
For Uniform Lighting SHR can be used as a Guide
SHR = spacing to height ratio
Take SHR and x by your ceiling height
e.g.: SHR of 0.8 x 2.4m ceiling height = 1.9 metre spacing between downlights
This gives even illuminance, if higher illuminance is required space closer together.
SCB Side clearance to building
HCB Height clearance to building elements
SCI Side clearance to building insulation
MIC Minimum clearance above building insulation for ventilation
Insulation type Class markings and Manufacturers specifications dictate what type of insulation is safe for each class of downlight