IP67 is always better than IP66 – right? Not necessarily!
IP ratings are defined in accordance with IEC 60529:
- the 1st digit denotes the protection against solids
- the 2nd digit denotes the protection against liquids
Many people wrongfully believe the higher the IP rating, the better. This is certainly not the case regarding protection against water ingress, as denoted by the 2nd digit.
- IPX1 – IPX6 are appropriate for luminaires intended to be installed above ground and classify the resistance to moisture ingress due to dripping, spraying, splashing or jets of water.
- IPX7 & IPX8 are appropriate for luminaires intended to be installed in-ground or underwater and classify resistance to moisture ingress due to temporary or permanent immersion/submersion in water.
The testing procedures for IPX1 – IPX6 are quite different to the procedures for IPX7 and IPX8.
We too often see luminaire manufacturers rate their above-ground exterior luminaires (including wall, ceiling, or post mounted) IP67, which many people infer as being even better than IP66. This may not actually be the case.
Whilst these luminaires may withstand temporary immersion in water in accordance with the IP67 testing, this ‘immersion in water’ rating is not relevant for these above-ground styles of luminaires and does not guarantee any level of protection against moisture ingress due to splashing or jets of water, which is far more relevant.
This is one of the reasons why we recommend WE-EF in-ground luminaires.
All WE-EF IP67 or IP68 rated in-ground luminaires are also specifically tested and rated IP66 to ensure a very high level of resistance to powerful water jets, which could well be encountered during routine cleaning over the life of the installation.
The longevity of exterior luminaires will depend on many attributes, including IP ratings. IP66 is generally considered the ‘gold standard’ for municipal grade above-ground luminaires providing the highest level of protection against water jets.
The quality of the seals is also important to ensure the IP rating is maintained over the life of the luminaire, which for most municipal applications is expected to be a min of 20 years. Many seals may provide high IP ratings when the luminaires are new (and tested) but will compress &/or harden over time resulting in a gradual degradation of resistance to moisture ingress.
That is why high-quality luminaires like those from WE-EF utilise non-ageing, silicone rubber, and CCG (Controlled Compression Gasket) seals to ensure IP ratings are maintained over the life of the luminaire.
Learn more about WE-EF luminaires
Download the technical extract of the General Catalogue from WE-EF to learn more about why WE-EF are our supplier of choice for in-ground exterior luminaires. Download here.