Environmental

Equipment operating in rugged operations environments such as military deployments must meet stringent environmental requirements. Equipment deployed outdoors or on vehicles is subjected to many environmental factors, such as vibration, shock, rainfall, water immersion, corrosion, temperature, altitude, and humidity. The equipment must operate normally despite the variations in environmental factors. Both industrial and defense organizations have developed standards, which ensure that products conform to the environmental range that is required for a particular application. The MIL-STD-810 standard was developed by the Department of Defense (DoD) and defines a test series, which may be tailored for any defense or commercial application. The International Electrotechnical Commission (IEC) maintains international standards for electrical and electronics equipment. The IEC 60529 standard defines International Protection (IP) ratings for products based on their ability to withstand various environmental factors. The National Electrical Manufacturers Association (NEMA) specifies and maintains manufacturing standards for electrical enclosures. Although IP ratings based on IEC 60529 and NEMA Type ratings are quite similar, they cannot be directly mapped. The IP ratings are based upon protection against ingress of solid objects and ingress of water, whereas NEMA Type ratings include all of that and in addition consider product features not addressed by IP ratings, such as corrosion, rust, icing, and construction details. Either one of more of the three standards (MIL-STD-810, IEC 60529, NEMA) are tailored based on the environmental needs of a procurer’s application. The resulting specification must be met by a vendor in order to pass the environmental criteria for procurement.

International Protection Rating (IP Rating)

The IEC 60529 standard that defines the IP rating focuses on protection against solid objects and liquids. The IP rating is specified as IP followed by two numbers. The first number is for protection against solid objects or the extent to which a person is protected against enclosed hazards (range 0-6), and the second number is for the extent of protection against water (range 0-8). These are further illustrated in the two tables.

NEMA Ratings

The NEMA standard defines ratings for electrical enclosures. A product’s enclosure is rated to protect against designated environmental conditions, such as water damage, dust, oil, or coolant. It also includes protection against corrosive agents such as acetylene or gasoline. Based on the extent of protection, an enclosure is qualified for a NEMA Type rating. The common NEMA Type enclosure ratings are listed in the following table. A complete list of enclosure types is available at the NEMA website.

A NEMA rating can be mapped to an IP rating because IP ratings are a subset of NEMA ratings, but the reverse is not possible because none of the IP ratings can fully meet any of the NEMA enclosure type requirements. The following table shows an approximate mapping from NEMA to IP rating.

MIL-STD-810G

The military standard MIL-STD-810, "Department of Defense Test Method Standard for Environmental Engineering Considerations and Laboratory Tests" specifies environmental design and test limits for the conditions that equipment will withstand throughout its service life. The test methods defined in the MIL-STD-810 test series replicate the effects of the environment on the equipment. Although the standard was specifically prepared for DoD applications, the standard also is used as the basis for commercial applications.

The military standard MIL-STD-810 series of test methods is issued by the US Army's Developmental Test Command, which is chartered under the Defense Standardization Program (DSP) with maintaining the functional expertise and serving as the DoD-wide technical focal point for the standard. The current document revision (2009) is Revision G (that is MIL-STD-810G) which was issued on October 31, 2008. The military standard MIL-STD-810 tests address a wide range of environmental conditions. The environmental management and engineering processes described within MIL-STD-810 can be of enormous value in generating confidence in the environmental worthiness and overall durability of a system design. The MIL-STD-810 test series contains environmental laboratory test methods that are applied using specific test tailoring guidelines described within the standard. The test methods defined in the MIL-STD-810 test series are tailored to generate the most relevant test data possible that can be incorporated into a system's final design specification. The procurement agencies specify the environmental conditions that could be encountered over the life of the system.

The Fortress Advantage

Fortress products have been proven to operate under the widest range of environmental parameters. All Fortress products are MIL-STD-810G certified and outperform competing products by a significant margin. Fortress offers the highest IP rating of IP67 in most of its products. IP67 is the highest rating possible for wireless network equipment as it is not required to deploy any equipment under water. Unlike some vendors who use off-the-shelf enclosures, Fortress’s expertise with designing high quality enclosures has enabled Fortress to build products that meet the special needs of the harsh outdoor environment. Fortress uses high-grade components that operate under a wide temperature range. An in-house heat chamber is used to validate the operating range of all products. All Fortress products undergo environmental tests for humidity, rain, sand and dust, and salt and fog, in addition to drop tests. MTBF (mean-time-between-failure) of Fortress products is in the range of 100,000 hours (~11 years of continuous operation). Latent failures uncovered by Electronic/Environmental Stress Screening (ESS) are also taken into account.

Fortress’s ES-series of products has been thoroughly evaluated and extensively deployed by the US Army's Combat Service Support Automated Information System Interface (CAISI), US Marine Corps, US Coast Guard and other military divisions. Fortress has established itself to be the leader in outdoor wireless networking solutions.