IP index in explosion-proof standards
The first digit indicates the level of protection that the enclosure provides against access to hazardous parts (e.g., electrical conductors, moving parts) and the ingress of solid foreign objects
1. Solid Ingress Protection
Level | Object size protected against | Effective against |
0 | — | No protection against contact and ingress of objects |
1 | >50 mm | Any large surface of the body, such as the back of a hand, but no protection against deliberate contact with a body part |
2 | >12.5 mm | Fingers or similar objects |
3 | >2.5 mm | Tools, thick wires, etc. |
4 | >1 mm | Most wires, screws, etc. |
5 | Dust protected | Ingress of dust is not entirely prevented, but it must not enter in sufficient quantity to interfere with the satisfactory operation of the equipment. |
6 | Dust tight | No ingress of dust; complete protection against contact (dust tight) |
2. Liquid ingress protection
The second digit indicates the level of protection that the enclosure provides against harmful ingress of water
Level | Protected against | Effective against | Details |
0 | Not Protected | — | — |
1 | Dripping water | Dripping water (vertically falling drops) shall have no harmful effect. | Test duration: 10 minutes Water equivalent to 1 mm of rainfall per minute |
2 | Dripping water when tilted up to 15° | Vertically dripping water shall have no harmful effect when the enclosure is tilted at an angle up to 15° from its normal position. | Test duration: 10 minutes Water equivalent to 3 mm rainfall per minute |
3 | Spraying water | Water falling as a spray at any angle up to 60° from the vertical shall have no harmful effect. | Test duration: 5 minutes Water volume: 0.7 liters per minute Pressure: 80–100 kPa |
4 | Splashing of water | Water splashing against the enclosure from any direction shall have no harmful effect. | Test duration: 5 minutes Water volume: 10 liters per minute Pressure: 80–100 kPa |
5 | Water jets | Water projected by a nozzle (6.3 mm) against the enclosure from any direction shall have no harmful effects. | Test duration: at least 3 minutes Water volume: 12.5 liters per minute Pressure: 30 kPa at distance of 3 m |
6 | Powerful water jets | Water projected in powerful jets (12.5 mm nozzle) against the enclosure from any direction shall have no harmful effects. | Test duration: at least 3 minutes Water volume: 100 liters per minute Pressure: 100 kPa at a distance of 3 m |
6K | Powerful water jets with increased pressure | Water projected in powerful jets (6.3 mm nozzle) against the enclosure from any direction, under elevated pressure, shall have no harmful effects. | Test duration: at least 3 minutes Water volume: 75 liters per minute Pressure: 1000 kPa at a distance of 3 m |
7 | Immersion up to 1 m | Ingress of water in harmful quantity shall not be possible when the enclosure is immersed in water under defined conditions of pressure and time (up to 1 m of submersion). | Test duration: 30 minutes Tested with the lowest point of the enclosure 1000 mm below the surface of the water, or the highest point 150 mm below the surface, whichever is deeper. |
8 | Immersion beyond 1 m | The equipment is suitable for continuous immersion in water under conditions which shall be specified by the manufacturer. However, with certain types of equipment, it can mean that water can enter but only in such a manner that it produces no harmful effects. | Test duration: continuous immersion in water Depth specified by the manufacturer, generally up to 3 m |
9K | Powerful high-temperature water jets | Protected against close-range high-pressure, high-temperature spray downs. | Test duration: – Water volume: 14–16 liters per minute Pressure: [8000–10000 kPa / 80–100 Bar] at distance of 0.1–0.15 cm Water temperature: 80 °C |