Its no fun when your flashlight decides to stop working in the middle of a job or out camping miles from any other light source but there is an information code that will at least tell us what sort of environment a flashlight can be used in and still keep going.
The IPX rating or to give its proper title the “Ingress Protection Rating” system is there for manufactures to inform customers of the general area of use a flashlight is suitable for and can also be a great selling point for those looking for a durable product.
Even though the IP code itself deals with other factors like equipments ability to resist solid objects from finding their way inside the main purpose of this article is to highlight the level of waterproofing when considering a new flashlight.
General Guide to the IPX Code for Flashlights
IPX0 : No promised additional protection other than what is coincidentally provided by the models design.
IPX1 : Will withstand short durations of light rainfall, this test is carried out with the flashlight in its default operating position.
IPX2 : Tested under the same level of rainfall as IPX1 but exposed to water in 4 different positions each 15 degrees from default operating position.
IPX3 : Flashlight will survive short durations of water sprayed at a maximum of 60 degrees from the vertical.
IPX4 : All round protection against the same levels of spraying water as IPX3 but thrown at the flashlight from all angles.
IPX5 : Tested against brief focused water jets while flashlight is rotated through all angles.
IPX6 : Heavier protection from spraying water with flashlight turned through all possible positions.
IPX7 : Able to survive total immersion in water for 30 minutes at a maximum depth of 1 meters.
IPX8 : Flashlight can be used reliably when under water but the details of depth and duration are laid out by the producer. This highest rating does give more flexibility than the others and this is where attention must be paid to the manufactures usage guidelines to avoid any mishaps with the product.
Cost vs Design
Producing a flashlight with a higher IPX rating means more money spent in the design phase and even more spent on each one unit produced to pass that rating onto the customer. From an engineering point of view smaller, less complicated designs are much easier to waterproof especially if they have to function under water for extended periods or contend with high water pressures.
A few specialized types of flashlights will allow water into certain parts of the casing but because of the way they are constructed this doesn’t effect the functionality at all.
Paying the extra cost for a fully immersible flashlight to use as a power outage backup for the home is a bit wasteful when a budget handy will do. Even here the IPX rating code has its purpose by telling you why a certain product is so expensive and ultimately saving money by guiding your buying choice based on how/where the flashlight is going to be used.
For further reading Wikipedia have a very detailed explanation on their IP rating page.