Anyone involved with industrial systems will have heard or used the term ‘IP rating’, but what does the term signify – and how does the IP rating of a product affect what you’re looking for?
IP Ratings Explained
IP rating in an embedded context is associated with a products resistance or susceptibility to the ingress of liquids or particles – think of it as Ingress Protection (although IP actually stands for International Protection)
There are two digits involved within an IP rating. The first digit is associated with solid ingress, ranging from no protection through to protection from large objects, such as human finger intrusion through to total protection from fine dust – rated on a scale of zero to 6.
The second digit or the IP rating refers to liquid ingress, normally water or steam. Care needs to be exercised here in interpreting the rating. For example, a panel PC with a rating of IP65 suggests its dust and waterproof but it’s often qualified with “from the front”. This means that the rear of the unit isn’t sealed and must be fitted into an instrument panel to obtain protection for the rear.
Summary & Overview of IP Ratings
First digit – solid ingress, ranging from zero (no protection) to 6 (dust tight)
Second digit – liquid ingress, ranging from zero (no protection) to 9K (powerful high temperature water jets)
- IP65 – Dust tight, protected against water projected from a nozzle
- IP66 – Dust tight, protected against heavy seas or powerful jets of water
- IP67 – Dust tight, protected against immersion. for 30 minutes at depths 150mm – 1000mm
- IP68 – Dust tight, protected against complete, continuous submersion in water
- IP69K – Dust tight, protected against high-pressure, high-temperature jet sprays, wash-downs or steam-cleaning procedures
For a complete detailed breakdown of IP levels, see here.
Your own practical experiences – at home or work
If you ever have cause to remove the cover from a desktop PC that’s been in use in a benign environment e.g. an office or home, you will almost certainly have been greeted by bundles of fluff.
As long as air flow is maintained this may not present a problem, but consider an industrial environment where the dust and fluff may become conductive or corrosive. Add this to the fact that the system may be controlling heavy equipment – a fast moving conveyor belt or a robot and the potential for operational problems or even break-down becomes clear.
What those ratings mean – and what you may need
Many manufacturers happily quote IP6X considering the 6 to be simply achieved. This isn’t the case and you should always seek test results if your application is dependent on the IP rating. This was reinforced to us some years ago with a unit we submitted for test. The application needed a rating of IP50 or better. Following the test, our engineer was surprised to find the unit full of fine power dust. A simple gasket and filter solved the problem but the pre-assumption that anything less than IP60 wouldn’t be a problem caused the original issue.
For a truly sealed unit, a rating of ‘IP67’ would mean the unit can be immersed in water up to 1metre in depth. For protection from steam jets, a rating of IP67K is required. A give away to the robustness of protection these units provide is their connections which are secured via screw in connectors, usually M12 type.
Thermal Cooling and EMC Shielding Practicalities
Where an IP rating is needed with the additional requirement to keep the system cooled, there are a number of challenges in ensuring the system is properly thermally managed in dissipating heat whilst jointly maintaining the required level of IP.
On a similar note, system door access and inspection panels provide their own challenges. Gasket materials must not only screen to achieve EMC requirements, but simultaneously protect against water and dust ingress. Careful thought and consequent mechanical design needs to be applied as there are some contradictory requirements where practical access to a system is involved.
We like to make life easier……
Here at BVM, we’ve been designing & qualifying systems against customer s IP and CE requirements for many years. From direct experience, we know where the challenges come from – and what provides for a successful design.
If you have a definite need for our services – or are just looking for exploratory conversations to further understand our abilities, call our engineering team on 01489 780144 to discuss your project.