There are further variations, which include measurements of resistance of an object to impact.
There are also various versions of this type of standard across the world, but the main one we are concerned with, when it comes to lighting sales in the UK, is presided over by the IEC *.
Generally, lighting manufacturers use the letters 'IP' followed by two numbers to classify how resistant their products are.
The first digit of the number indicates how well protected the item is from solid objects, such as dust, or, to look at it another way, how well protected the user is from accidentally inserting a finger into contact with something hazardous. The second digit of the same number refers to water ingress.
For consumers, this scheme is particularly designed to indicate which type of fittings are suitable for environments such as bathrooms, or for outdoor use. The table below shows some of the most commonly used IP ratings, and what they refer to.
First Digit of the IP Code
Digit | Size of ingress object | Effective against |
---|---|---|
0 | ... | No protection |
1 | more than 5cm (c.2 in.)in width | Protection against accidental insertion of a hand, leg etc. (not normally applicable to lighting). |
2 | more than 12.5mm (about half an inch) | Protection for fingers, or similarly sized objects. |
3 | more than 2.5mm | This protects against insertion of a small screwdriver or piece of wire. |
4 | more than 1 mm | Protects down to the level of narrow gauge wire and nails etc. |
5 | Dust-particle size | Provides good protection against dust, but not 100%. |
6 | Dust-tight | Complete protection from entry of even fine dust. |
Second Digit of the IP Code
Digit | Water Protection Level | Test that needs to be Passed |
---|---|---|
0 | No protection | ... |
1 | Dripping Water | Vertical water drops have no effect, for a duration of 10 minutes; equivalent to 1mm rainfall per minute. |
2 | Dripping Water @ 15° | Vertically dripping water does not harm the fitting when the casing is tilted up to 15° from its normal position, during 10 minutes of testing; equivalent to 3mm of rain per minute. |
3 | Water Spray | Water spraying at any angle up to 60° has no harmful effect, during a 5-minute test; three-quarters of a litre of water per minute sprayed, at a pressure of 80-100 kilo-Newtons per square metre. |
4 | Splashing Water | Water splashing against the fitting's casing has no deleterious effect from any direction, during a 5-minute test with 10 litres of water splashed at a pressure of 80-100 kilo-Newtons per square metre. |
5 | Water Jet | Water hosed in a 6mm jet from any direction does not damage, for at least 3 minutes, with 12.5 litres of water projected at 30 kilo-Newtons per square metre pressure. |
6 | Strong Water Jet | Water sent from 12.5mm jets, at any angle, has no harmul consequence; tested for 3 minutes, with a water volume of 100 litres per minutes at 100-160 kilo-Newtons per square metre pressure. |
7 | Total Immersion @ 1m | Device not affected if immersed in water up to 1m in depth for 30 minutes. |
8 | Immersion beyond 1m | Device suitable for continuous water immersion for a time and pressure specified by the manufacturer. |
* IEC (International Electrotechnical Commission) is the body which should be consulted for definitive information (http://www.iec.ch/).