IP … NEMA … What Does It All Mean and What’s Best for My Wash-Down Application!?
In my last post I talked about UL Listed versus Recognized. This time we are going to take a look at the IP and NEMA ratings and what they mean. With this information you should be able to decide what minimum level of protection you need for your application.
Let’s start with the basics. What does IP and NEMA stand for? IP stands for ingress protection and NEMA stands for National Electrical Manufacturers Association. Both IP and NEMA are rating systems for equipment that might be exposed to liquids, rain, ice, corrosion and contaminates such as dust.
An IP number contains two numbers (i.e. IP65) in most instances which relate to the level of protection provided by an enclosure or housing. The first number relates to protection from solids as follows:
0: No Special Protection
1: Protected against solid objects up to 50 mm in diameter
2: Protected against solid objects up to 12 mm in diameter
3: Protected against solid objects up to 2.5 mm in diameter
4: Protected against solid objects up to 1 mm in diameter
5: Dust protected
6: Dust tight
The second number relates to protection from liquids as follows:
0: No special protection
1: Protected against dripping water
2: Protected against dripping water when tilted up to 15o from normal position
3: Protected against spraying water
4: Protected against splashing water
5: Protected against water jet spray
6: Protected against heavy jet spray
7: Protected against the effects of immersion
8: Protected against submersion
Example: IP66 = Dust tight and protected against heavy water jet spray
As you can see the IP rating system is pretty straight forward. Now let’s look at the NEMA rating system. The list below shows the different NEMA ratings and how they compare to each other.
NEMA 1: General purpose. Protects against dust, light, and indirect splashing, but is not dust-tight; primarily prevents contat with live parts; used indoor and under normal atmospheric conditions.
NEMA 2: Drip-tight. Similar to type 1 but with addition of drip shields; used where condensation may be severe (as in cooling rooms and laundries)
NEMA 3 and 3S: Weather-resistant. Protects against weather hazards such as rain and sleet; used outdoors on ship docks, in construction and in tunnels and subways.
NEMA 3R: Intended for outdoor use. Provides a degree of protection against falling rain and ice formation. Meets rod entry, rain, external icing and rust-resistance design tests.
NEMA 4 and 4x: Weather tight (weatherproof). Must exclude at least 65 GPM of water from 1 inch nozzle delivered from a distance of not less than 10 feet for 5 minutes. Used outdoors on ship docks, in dairies and breweries.
NEMA 5: Dust-tight. Provided with gaskets or equivalent to exclude dust; used in steel mills and cement plants.
NEMA 6 and 6P: Submersible. Design depends on specific conditions of pressure and time; submersible in water; used in quarries, mines and manholes.
NEMA 7: Hazardous. For indoor use in Class I Groups A, B, C and D environments as defined in the National Electric Code (NEC).
NEMA 8: Hazardous. For indoor and outdoor use in locations classified as Class I Groups A, B, C and D as defined in the NEC.
NEMA 9: Hazardous. For indoor and outdoor use in locations classified as Class II Groups E, F or G as defined in the NEC.
NEMA 10: MSHA. Meets the requirements of the Mine Safety and health Administration, 30 CFR part 18 (1978).
NEMA 11: General-purpose. Protects against the corrosive effects of liquids and gasses. Meets drip and corrosion resistance tests.
NEMA 12 and 12 K: General-purpose. Intended for indoor use, provides some protection against dust, falling dirt and dripping non-corrosive liquids. Meets drip, dust and rust resistance tests.
NEMA 13: General-purpose. Primarily used to provide protection against dust, spraying of water, oil and noncorrosive coolants. Meets oil exclusion and rust resistance design tests.
NEMA ratings can be approximately compared to those of the IP system as shown below. Other factors such as corrosion protection are involved in the NEMA system, please refer to official documentation for details.
NEMA 1 = IP10
NEMA 2 = IP11
NEMA 3 = IP54
NEMA 4 = IP56
NEMA 4X = IP66
NEMA 6 = IP67
NEMA 12 = IP52
NEMA 13 = IP54
In the world of mass flow products the most common classifications are NEMA 4 / 4x, IP65, IP66 and IP67. The chart below shows how these compare as far as testing requirements for water resistance.
|Rating||Nozzle Size||Flow Rate||Distance||Direction||Time|
|NEMA4 / 4x||25.4 mm||240 lpm||3-3.5 m||All||5 min|
|IP65||6.3 mm||12.5 lpm||2.5-3 m||All||3 min|
|IP66||12.5 mm||100 lpm||2.5-3 m||All||3 min|
|IP67||Immersion tank||NA||15 cm - 1 m||NA||Temporary|
The Brooks SLAMf and Mf Series products conform to IP66 and NEMA 4/4x. Many Life Science customers use what is referred to as open frame systems. These systems and the devices in them are often exposed to a hose down wash process. For this reason the SLAMf and Mf Series products are used in this application. In my opinion, IP66 is the best rating for this application. Some mass flow controller suppliers sell devices with IP67 ratings into this application, but, as you can see from the above chart, this rating does not test the device for the impact of a jet spray at all.
I hope this gives you a better understanding of the IP and NEMA rating systems and what might be important for your application.
I think it is going to be Canadian Registration Numbers (CRNs) in my next post. We are neck deep in getting CRNs for several of our products so it is definitely top of mind for me. Till next time.