International protection rating or ingress protection rating?

Friday, 14 December, 2007

What's in a name? For some, IP is intellectual property, but if you are rating your equipment or enclosures IP gives a quantifiable measure of protection against intrusion by either solids or liquids.

Interestingly, IP stands for International Protection Code and Ingress Protection Code. Both seem to be interchangeable but Ingress Protection is the most common definition.

The IP Code, specified in Australian Standards AS60529 and also EN60529 and IEC 60529, consists of two numbers and an optional letter, for example IP67. The larger each digit the greater the protection.

The first digit represents the level of protection against solid objects. It ranges from 0 which means no protection, through protection against large objects such as hands (1) to total protection against dust ingress (6).

The second digit in the IP Code represents protection against liquid ingress. Once again, 0 implies no protection. Numbers 1 to 6 give increasing protection from falling drops of water through sprays up to high pressure water jets.

A rating of 6 will cover you for ratings 1 to 5 for both solid and liquid protection.

Liquid protection ratings of 7 and 8, however, are separate. These digits give a measure of protection against immersion but do not imply spray protection as well.

There may be additional letters after the two digits. These letters can be appended to classify the level of protection against access to hazardous parts by humans. For example:

A - back of the hand, B - finger etc.

Further information can be appended that relates to the protection of the device: H - high-voltage device, M - device moving during water test etc.

The standard does not specify standards of protection against risks of explosions or conditions such as moisture (produced, for example, by condensation), corrosive vapours, fungus or vermin.

IP69K and the food processing industry

The IP Code does not cover enclosures that are subjected to high temperature and high pressure washdowns such as those found in the food industry. The Germans issued standard DIN 40050-9 which extends the IEC 60529 rating system with the IP69K rating. Initially developed for road vehicles, especially those like cement mixers that need intensive cleaning, IP69K is particularly useful in the food industry.

The IP69K test involves close range, low volume and very high pressure - similar to that experienced in the food and beverage industry.

Products rated to IP69K must be able to withstand high-pressure and steam cleaning. The test specifies a spray nozzle that is fed with 80°C water at 80-100 bar and a flow rate of 14-16 L/min. The nozzle is held 10-15 cm from the tested device at angles of 0°, 30°, 60° and 90° for 30 seconds each while the test device sits on a turntable that rotates once every 12 seconds.

Possibly the best advice is to buy a copy of the standard, decide what level of protection you, your equipment and enclosures need and then purchase equipment with the appropriate IP rating.

IP (1st digit) Protection of equipment against solid objects Tested by Meaning for protection of persons
0 No protection None No protection
1 Solid objects 50 mm 50 mm dia. sphere applied with 50 N force. Accidental touch by back of hand
2 Solid objects 12.5 mm 12.5 mm dia. sphere applied with 30 N force. Accidental touch by fingers
3 Solid objects 2.5 mm 2.5 mm dia. steel rod applied with 3 N force. Accidental touch by tool
4 Solid objects 1 mm 1 mm dia. steel wire applied with 1 N force. Accidental touch by small wire
5 Dust-protected (limited ingress, no harmful deposit) Dust chamber with or without under-pressure. Accidental touch by small wire
6 Dust-tight (totally protected against dust) Dust chamber with under-pressure. Accidental touch by small wire

IP test summary (1st digit)

IP (2nd digit) Protection against water with harmful effects Tested by Meaning for protection from water
0 No protection None None
1 Vertically dripping Drip box for 10 min. Falling drops of water, condensation
2 Dripping - 15° tilted Drip box, 2.5 min. per side Direct light streams of water, up to 15° from the vertical
3 Spraying Oscillating tube ±60°, 10 min., 10 L/min. Direct sprays of water, up to 60° from the vertical
4 Splashing Oscillating tube ±180°, 10 min., 10 L/min. Water sprayed from all directions, limited ingress
5 Jetting 6.3mm dia. nozzle from 2.5 to 3 m distance,12.5 L/min. for 3 min. Low pressure water jets from all directions, limited ingress

IP test summary (2nd digit)

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