The operation of electronic apparatus such as televisions, radios, computers, medical instruments, business machines, and communications equipment is attended by the generation of electromagnetic radiation within the electronic circuitry of the apparatus. Such radiation often develops as a field or as transients within the radio frequency band of the electromagnetic spectrum and is termed electromagnetic interference (EMI), which is known to interfere with the operation of other proximate electronic devices. Sensitive electronics are often prone to radio frequency interference (RFI) as well as electromagnetic interference (EMI) at frequencies ranging up to several megahertz. The electrical performance of an analog or digital circuit can be impaired significantly by such types of interference. Sources of the RFI, EMI, and vibrational energy are assumed to be external to the enclosure and may include other high frequency electronics, electrical motors, transformers, AC power lines, electrical switches, electrical lighting, loudspeaker output, etc. To attenuate EMI effects, shielding having the capability of absorbing and/or reflecting EMI energy may be employed both to confine the EMI energy within a source device, and to insulate that device or other "target" devices from other source devices. Such shielding is provided as a barrier which is interposed between the source and the other devices, and typically is configured as an electrically conductive and grounded housing which encloses the device. An EMI shield allows operation in an electromagnetic environment at an optimal level of efficiency, and allows static charges to be drained to a frame ground.

As electronic components have become faster and more powerful, thermal management has become a critical issue. Electronic cabinets, enclosures, housings, compartments, and cells often house heat producing equipment. Internal energy in the form of heat from the equipment can build up over time, resulting is excessively high internal enclosure temperatures, causing equipment reliability problems or equipment failure. The control of the internal temperatures in enclosures is referred to as thermal management. A thermal control system is required to maintain the operability of electronic components disposed within an enclosure located in a hostile environment. The most common way to remove heat from an electronic component is through a metallic heat sink attached to the component. Heat travels by conduction from the component to the heat sink's fins which then radiate the heat into the surrounding air within the enclosure. The heat sink is a relatively large mass of thermally conductive material, such as metal, which conducts heat away from the electrical component and the interior of the enclosure to a location where the heat may be dissipated into the air. A fan installed on an enclosure wall forces hot air away from the heat sink fins and out of the enclosure. As a result, the temperature of the electrical component is maintained within a predetermined operating range so as to prevent damage thereto. To effectively perform this heat transferring function, the electrical component must be maintained in direct physical contact with a surface of the heat sink. Modular ventilation fan assemblies, sometimes called fan tray assemblies are used for mounting ventilation fans to electronics enclosures, such as computer enclosures. Fan trays are often mounted to the electronics enclosures using a pair of opposing side rails that engage corresponding rails in the electronics enclosure. The fan tray may be secured to the enclosure using a screw or like fastener after being slid into place along the rails.

Passive cooling methods for cooling electronics enclosures are also known. Passive cooling relies on conduction and radiation to passively cool the electronics equipment inside an enclosure without fans, air conditioners, or heat exchangers. It is known to provide openings in the enclosure, called vents, for this purpose. Ventilated enclosures are sometimes used to cool electronics equipment inside an enclosure or cabinet. Ventilated enclosures use natural or forced convection to draw ambient air through the cabinet to cool the equipment inside the enclosures. The particular size and arrangements of the vents is determined by the airflow requirements for adequate cooling, and may also be affected by aesthetic considerations. Passive cooling of electronics enclosures is less expensive than active cooling systems, reduces energy consumption, and minimizes noise. Additionally, because there are fewer components to fail, passive cooling systems are generally more reliable and robust than active cooling systems. However, the electronics inside passive cooling enclosures such as the ventilated cabinet are exposed to the air flow, which may contain environmental contaminants, such as moisture, nitrates, hydrocarbons, sulfur dioxide, nitrogen oxides, hydrogen sulfides, chlorine, ozone, and salt. Thermal management strategies may often conflict with the requirement that an enclosure protect the equipment from the external environment. The application and performance of thermal management systems significantly affect an enclosure. Adverse effects of thermal management systems include costs, performance, power consumption, restrictions to equipment configuration, and limitations to the overall use of the cabinet.

Various enclosures are known for housing electronic equipment. Enclosures are usually formed of rigid materials such as metals or polymeric materials to protect the internal electronic circuitry. Electronics are often housed within an enclosure formed of either aluminum, steel, or plastic. Plastic enclosures offer no protection from RFI or EMI unless they are sprayed with a highly conductive coating and properly grounded. Steel enclosures offer some protection from magnetically generated interference, but sacrifice a significant degree of RFI protection due to the fairly poor electrical conductivity of steel at very high frequencies. This can be remedied somewhat by plating the steel with a very conductive metal such as copper. However, steel is still not entirely effective in preventing low frequency magnetic interference. An aluminum enclosure offers good protection from RFI and very high frequency EMI due to its high degree of electrical conductivity, but provides very little protection from EMI at frequencies below 100 kHz since they are not magnetically permeable. An integrated EMI shielding solution for electronics enclosures involves the over-molding of the housing or cover with an conductive elastomer. The elastomer is integrally molded in a relatively thin layer across the inside surface of the housing. The housing may be provided with a conductive coating generally applied across the interior surfaces of the housing. The coating may be an electrically-conductive paint, a conductively-filled, molded elastomeric layer, a metal foil laminate or transfer, or a flame-sprayed or other deposited metal layer. A conductive gasket may be used to provide electrical continuity between the coating layers applied to the various mating housing parts.

Generally, the electronic enclosures have an upstanding frame provided with mounting holes for the attachment of shelf members that support the electronic equipment. The frame typically defines a central shelf receiving cavity into which the shelves are disposed, and panels or doors are often supported on the frame to provide an enclosure cabinet. Enclosures for housing electrical and mechanical equipment are typically constructed of either steel or aluminum alloys which require an extensive internal frame or utilize exterior skin material as the support structure for the enclosure. Plastic enclosures have been utilized to house primarily small non-energy producing thermal dissipating equipment. Miniature electronic enclosures are increasingly used to support and protect electronic crystals, transistors, and other devices. These enclosures consist of bases or headers and matching cans or covers. These enclosures provide protection from atmosphere, moisture, and other factors that can degrade their performance of electronic devices. One of the most reliable and cost-effective methods of constructing bases or headers employs the use of certain glass and metal alloys that can be bonded to each other through the use of various processes. Most enclosure has one or more openings or ports. The openings can be used to gain access to internal components for installation and maintenance. The openings can also be used to connect accessory devices or add expansion modules, for example. The openings are covered to prevent the release of energy that might disrupt neighboring devices. Enclosures for electronic modules are known which include hinged front covers. Enclosures which have large cutout portions in their bottom wall which are supported by a frame structure sag because of the lack of structural integrity and provide for excessive flexing when subjected to shock and vibration testing.

Computer systems such as general purpose computers typically include housings for enclosing various components and circuitry associated with operating the general purpose computers. A typical computer enclosure includes a chassis, an expansion card seat, a front bezel and a plurality of components connectable to external apparatus and systems. In computing systems, computer peripheral electronic devices, such as disk drives and tape drives, are mounted in shelf frames containing a plurality of the devices. Each peripheral device is mounted in an enclosure, and the enclosure is then mounted in the shelf frame. A plurality of frames may be mounted in a cabinet. The cabinets generally serve to shield and protect the components and circuitry from adverse conditions such as impact and dust. The cabinets also generally serve to define the shape or form of the general purpose computers. In most cases, the cabinets take the form of a box, as for example, the housings associated with tower style computers. The enclosure typically comprises a plurality of panels connected to each other with screws or similar fasteners. Some computer enclosures adopt hooks to reduce or even eliminate the need for screws. Hooks formed on panels of the enclosure engage in recesses defined in other panels of the enclosure. Several key requirements are specified when the enclosure is utilized for notebook computers. The enclosure should be rigid, but light in weight, so that it can be hand-carried. The enclosure should be resistant to cracking or breaking. Further, the enclosure should be thermally conductive to dissipate heat, so that heat generated by internal components, such as power supplies, can be adequately transferred to the outer surface.

When telecommunications equipment is deployed in outdoor locations, a cabinet or enclosure protects the electronics from weather and environmental contaminants. Since such enclosures are located outdoors, they must be substantially weather tight in order to protect the electronic connections from adverse environmental conditions such as wind, rain, snow and flooding. These enclosures also have to be relatively secure in order to guard against entry by unauthorized personnel and durable in order to withstand the wear-and-tear associated with being located in an outdoor environment. To accomplish this objective, these enclosures may be formed in a variety of shapes and may be made from a variety of materials such as, for example, metal, polymer, plastic, ceramic, glass, crystal, and/or combinations thereof. Typically, the protection is achieved in part by positively pressurizing the enclosures to prevent potentially damaging and undesirable moisture and dust from infiltrating and reaching the electronic equipment. Pedestal style electronics enclosures are used in telecommunications systems to house splices or terminal connections between service wires or distribution wires and buried telephone cables. Pedestal enclosures are also used to house connections to other types of buried utility cables such as for cable television or power distribution.