I think I became aware of Coughtrie soon after buying a house in Glasgow in 1984 - as 2 of the SP10 units were fitted to the outside of the building.  I discovered happily that the firm was in Glasgow and went to buy another bigger SP10 (150W) to put over a garage after visiting the Hillington factory  (It cost £12.93 in August 1986!). I brought this one to my next house here in the South of England. I remember seeing these SP10 fittings everywhere and realised they must be the sort of good quality item specified by architects and other professionals. Pay more and get a quality item, that really lasts, and for which you can get spares years later. This suits me as someone who wants goods that do not break down within a few months, repairs things and keeps them going.  In the 1980s and 1990s this was NOT the zeitgeist at the retail level, but now I think it is becoming the proper thing to do, and rather "green"!

Paul M, South of England

IK Ratings For Impact Resistant Luminaires: Everything You Need To Know

IK Equivalence

The IK rating is a vital tool for specifying luminaires especially in challenging environments. The IK rating was developed out of the old IP code which had a third digit to indicate impact resistance. 

The IK rating test is simple in principle; a weight of known value is dropped from a known height, to deliver an impact of a fixed energy, measured in joules. To achieve the IK rating a luminaire must survive a minimum of three identical impacts from test rigs such as pendulum, spring or dropped hammers.

Why is IK so important?

A broken luminaire is a hazard especially in public areas, either from debris or lack of required illumination. Damage entails additional costs to repair or replace quite apart from the potential need to close busy areas to access.

What IK do you need?

It depends on your risk assessment. In a low traffic area where there is little chance of damage, a rating of IK7 or below is likely to suffice. In areas where there is high traffic or risk of vandalism the top-rating of IK10 is recommended.

Is IK10 the best there is?

IK10 rating is the top of the official scale measured (IEC/BS EN 60598-1). The meaning of IK10++ is straightforward, in that the manufacturer has tested to exceed the standard but IK11 or more do not exist in the current regulations.