Rugged Rating Organizations and Standards
Ratings are set by various government agencies, industry groups and/or independent laboratories and are cited by manufacturers in order to establish a more exact degree of environmental protection and reliability. Some of the more common standards include:
IP Ratings (Ingress Protection) Rating for Equipment and Enclosures
A three-digit number established by the International Electrotechnical Commission, is used to provide an IP Rating to a piece of electronic equipment or to an enclosure for electronic equipment. The IP code indicates the level, or amount of the protection.
The three digits represent three different forms of environmental influence:
The first digit represents protection against ingress of solid objects.
The second digit represents protection against ingress of liquids.
The third digit represents protection against mechanical impact damage.
(*The third digit is often omitted, resulting in a 2-digit IP Rating covering ingress against solid objects and liquids only).
The larger the value of each digit, the greater the protection from that influence. As an example, a product rated as IP573 would be better protected against environmental factors than another similar product that was only rated as IP432.
|First Number (Solids)||Second Number (Liquids)||Third Number (Mechanical Impact)|
|0||No protection||No protection||No protection|
|1||Protected against solid objects over 50mm e.g. hands, large tools.||Protected against vertically falling drops of water or condensation.||Protected against 0.225 joule impact (150g @ 15cm).|
|2||Protected against solid objects over 12mm e.g. hands, large tools.||Protected against direct sprays of water up to 15° from vertical.||Protected against 0.375 joule impact (250g @ 15cm).|
|3||Protected against solid objects over 2.5mm e.g. wire, small tools.||Protected against direct sprays of water up to 60° from vertical.||Protected against 0.5 joule impact (250g @ 20cm).|
|4||Protected against solid objects over 1.0mm e.g. wires.||Protected against water sprayed from any direction. Limited ingress permitted.|
|5||Limited protection against dust ingress (no harmful deposit)||Protected against low pressure water jets from any direction. Limited ingress permitted.||Protected against 2.0 joule impact (500g @ 40cm).|
|6||Totally protected against dust ingress.||Protected against high pressure water jets from any direction. Limited ingress permitted. (Shipdeck)|
|7||N/A||Protected against the effects of immersion between 15cm and 1M.||Protected against 6.0 joule impact (1.5Kg @ 40cm).|
|8||N/A||Protected against long periods of immersion under pressure.|
Protected against 20 joule impact (5Kg @ 40Protected against 0.225 joule impact (150g @ 15cm).cm).
NEMA stands for the National Electrical Manufacturers Association. They provide a forum for the standardization of electrical equipment, enabling consumers to select from a range of safe, effective, and compatible electrical products. The organization has also made numerous contributions to the electrical industry by shaping public policy development and operating as a central confidential agency for gathering, compiling, and analyzing market statistics and economics data.
Environmental ratings for enclosures based on "NEMA" Type designations
|Enclosure Type Designation||Intended Use and Description|
|1||Indoor use primarily to provide a degree of protection against limited amounts of falling dirt.|
|2||Indoor use primarily to provide a degree of protection against limited amounts of falling water and dirt.|
|3||Outdoor use primarily to provide a degree of protection against rain, sleet, wind blown dust and damage from external ice formation.|
|3R||Outdoor use primarily to provide a degree of protection against rain, sleet, and damage from external ice formation.|
|3S||Outdoor use primarily to provide a degree of protection against rain, sleet, windblown dust and to provide for operation of external mechanisms when ice laden.|
|4||Indoor or outdoor use primarily to provide a degree of protection against windblown dust and rain, splashing water, hose-directed water and damage from external ice formation.|
|4X||Indoor or outdoor use primarily to provide a degree of protection against corrosion, windblown dust and rain, splashing water, hose-directed water, and damage from external ice formation.|
|5||Indoor use primarily to provide a degree of protection against settling airborne dust, falling dirt, and dripping noncorrosive liquids.|
|6||Indoor or outdoor use primarily to provide a degree of protection again hose-directed water, and the entry of water during occasional temporary submersion at a limited depth and damage from external ice formation.|
|6P||Indoor or outdoor use primarily to provide a degree of protection against hose-directed water, the entry of water during prolonged submersion at a limited depth and damage from external ice formation.|
|7||Indoor use in locations classified as Class I, Division 1, Groups A, B, C or D hazardous locations as defined in the National Electric Code (NFPA 70) (Commonly referred to as explosion-proof).|
|8||Indoor or outdoor use in locations classified as Class I, Division 2, Groups A, B, C or D hazardous locations as defined in the National Electric Code (NFPA 70) (commonly referred to as oil immersed).|
|9||Indoor use in locations classified as Class II, Division 1, Groups E, F and G hazardous locations as defined in the National Electric Code (NFPA 70) (commonly referred to as dust-ignition proof).|
|10||Intended to meet the applicable requirements of the Mine Safety and Health Administration (MSHA).|
|12 and 12K||Indoor use primarily to provide a degree of protection against circulating dust, falling dirt, and dripping noncorrosive liquids.|
|13||Indoor use primarily to provide a degree of protection against dust, spraying of water, oil, and noncorrosive coolant.|
Conversion of "NEMA" Type to "IP" Code designations*
|Type Number||IP Designation|
|4 and 4X||IP56|
|6 and 6P||IP67|
|12 and 12K||IP52|
* Table cannot be used to convert "IP" Codes to "NEMA" Types. See NEMA 250 for additional details.
MIL-STD (Military Standard) or MIL SPEC (Military Specification)
Is a series of performance and manufacturing guidelines set by the US Department of Defense for military and commercial equipment and applications. These guidelines specify allowable parts and environmental condition ranges that a tool or other device must be able to operate in to meet compliance.
MIL-STD 810 E and F are generally accepted as the highest standard for ruggedized testing by mobile computer manufacturers.
MIL-STD-810G testing is for a range of extreme conditions including 72" drops, shocks, vibration, humidity, altitude, rain-, dust- and sand-resistance, temperature extremes and thermal shock. MIL-STD-810G, which was created in October 2008, supersedes MIL-STD-810F.
MIL-STD 810 test method is used to generate confidence in the environmental worthiness and overall durability of material system design. The testing process follows guidelines which include program documentation, program roles, test standards and laboratory test method guidelines for all categories. The laboratory test methods are broken down into 24 categories. The required compliance test categories include:
|Low Pressure (Altitude)||Method 500.4|
|High Temperature||Method 501.4|
|Low Temperature||Method 502.4|
|Temperature Shock||Method 503.4|
|Contamination by Fluids||Method 504|
|Solar Radiation (Sunshine)||Method 505.4|
|Salt Fog||Method 509.4|
|Sand and Dust||Method 510.4|
|Explosive Atmosphere||Method 511.4|
|Acoustic Noise||Method 515.5|
|Acidic Atmosphere||Method 518|
|Gunfire Vibration||Method 519.5|
|Temperature, Humidity, Vibration, and Altitude||Method 520.2|
|Icing/Freezing Rain||Method 521.2|
|Ballistic Shock||Method 522|
Before testing can begin, the item has to have environmental exposure, which means that the test item is run under standard ambient conditions to ensure the item is operating properly and to ensure pretest baseline performance data is collected.
The actual tests are carried out according to pre-defined test plans and criteria. The tests can be laboratory or natural environment field tests, or a combination, which ever applies. The test procedure is dependent on the environment tested. The procedure(s) and its execution provide the basis for collecting the necessary information.
After completion of each environmental test, the post-test data is examined and recorded in accordance with material specifications and program guidelines. The results are compared with the pre-test data. The post test record includes: test sequence used, deviations from planned test program, performance data, test conditions and a signature of the test team, to name a few. A final test report will be created for each test which includes an analysis of the test results.
You may notice some products will carry a MIL-STD 810E rating and some may state they are MIL-STD 810F compliant. MIL-STD 810F is a revision of MIL-STD 810E. The tests and methods are basically the same but much of the standard has been rewritten to provide clearer direction. Many of the changes that can be found with the MIL-STD 810F are minor or administrative in nature, but technical changes and improvements can be found throughout (i.e. additional technical testing guidelines).
IS (Intrinsic Safety)
IS is a term representing the Hazardous Location classifications as described in the National Fire Protection Association's (NFPA) National Electrical Code (Article 500). The National Electrical Code (NEC) defines Hazardous Locations as those areas "where fire or explosion hazards may exist due to flammable gases or vapors, flammable liquids, combustible dust, or ignitable fibers or flyings."
An intrinsic safety rating details the specific Hazardous Location in which an electrical device can be used without fear of electrostatic discharge that may cause an explosion.
SUMMARY OF CLASS I, II, III HAZARDOUS LOCATIONS
|CLASSES||GROUPS||DIVISION I||DIVISION 2|
|I. Gases, vapors and liquids||A: Acetylene
B: Hydrogen, etc
C: Ether, etc
D: Hydrocarbons, fuels, solvents, etc
|Normally explosive and hazardous||Not normally present in explosive concentrations (but may accidentally exist)|
|II. Dusts||E: Metal dusts
F: Carbon dusts
G: Flour, starch, grain, plastic, chemical dust
|Ignitable quantities normally or possibly in suspension||Dust not normally suspended in an ignitable concentration (but may exist)|
|III. Fibers and flyings||Textiles, wood-working etc.||Handled or used in manufacturing||Stored or handled in storage|