IEC Dimensions of Mechanical Structures of the mm (19 in) Series Part 1: Panels and Racks. IEC Mechanical structures for electronic equipment – Dimensions of mechanical structures of the ,6 mm (19 in) series – Part Basic. IEC Dimensions of Mechanical Structures of the mm (19 Inch) Series Part 2: Cabinets and Pitches of Rack Structures.
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A inch rack is a standardized frame or enclosure for mounting multiple electronic equipment modules. Each module has a front panel that is 19 inches The inch dimension includes the edges, or “ears”, that protrude on each side which allow the module to be fastened to the rack frame with screws.
Common uses include server, telecom, broadcast video, lighting, audio, and scientific lab equipment. Equipment designed to be placed in a rack is typically described as rack-mountrack-mount instrumenta rack mounted systema rack mount chassissubrackrack mountableor occasionally simply shelf.
The height of the electronic modules is also standardized as multiples of 1. The term relay rack appeared first in the world of telephony. The inch rack format with ie of 1. The earliest repeaters from were installed in ad-hoc fashion on shelves, in wooden boxes and cabinets.
Ifc serial production started, they were built into custom-made racks, one per repeater. The height of the different panels will vary, 6027it was an established standard with holes tapped for screws with alternating spacings of 1.
The inch ieec format has remained constant while the technology that is mounted within it has changed considerably and the set of fields to which racks are applied has 602297 expanded. Nineteen-inch racks in two-post or four-post form hold most equipment in modern data centersISP facilities, and professionally designed corporate server rooms.
They allow for dense hardware configurations without occupying excessive floorspace or requiring shelving. Nineteen-inch racks are also often used to house professional audio and video equipment, including amplifierseffects unitsinterfaces, headphone amplifiers, and even small scale audio mixers. A third common use for rack-mounted equipment is industrial power, control, and automation hardware. Thus, a 1U rackmount computer is not 1.
This gap allows a bit of room above and below an installed piece of equipment so it may be removed without binding on the adjacent equipment. Originally, the mounting holes were tapped with a particular screw thread.
When rack rails are too thin to tap, rivnuts or other threaded inserts can be used, and when the particular class of equipment to be mounted is known in advance, some of the holes can be omitted from the mounting rails. Threaded mounting holes in racks eic the equipment is frequently changed are problematic isc the threads can be damaged or the mounting screws can break off; both problems render the mounting hole unusable.
Tapping large numbers of holes that may never be used is 6097 nonetheless tapped-hole racks are still in use, generally for hardware that rarely changes. Examples include telephone exchanges, network cabling panels, broadcast studios and 6027 government and military applications.
The holes are large enough isc permit a bolt to be freely inserted through without binding, and bolts are fastened in place using cage nuts.
In the event of a nut being stripped out or a bolt breaking, the nut can be easily removed and replaced ieec a new one. Production of clearance-hole racks is less expensive because tapping the holes is eliminated and replaced with fewer, less expensive, cage nuts. The next innovation in rack design has been the square-hole rack. Square-hole racks allow boltless mounting, such that the rack-mount equipment only needs to insert through and hook down into the lip of the square hole. 60927 and removal of hardware in a square hole rack is very easy and boltless, where the weight of the equipment and small retention clips are all that is necessary to hold the equipment in ie.
Older equipment meant for round-hole or tapped-hole racks can still be used, with the use of cage nuts made for square-hole racks. Rack-mountable equipment ifc traditionally mounted by bolting or clipping its front panel to the rack. With the prevalence of inch racks in the Telecoms industry, the same practice is also common, but with equipment having inch and inch brackets available, enabling them to be mounted in existing racks.
A key structural weakness of front-mounted support is the shear stress placed on the mounting rails and the leading edge of the equipment. As a result, 4-post racks have become common, with such racks featuring a mirrored pair of rear mounting posts. APC SX-range racksit is common for equipment that features 4-post mounting brackets to have an adjustable rear bracket.
Servers and deep pieces of equipment are often mounted using rails that are bolted to the front and rear posts as above, it is common for such rails to have an adjustable depthallowing the equipment to be supported by four posts, while also enabling it to be easily installed and removed. This of course varies by manufacturer, the design of the rack and its purpose, but through common constraining factors such as raised floor tile dimensionsthese dimensions have become quite common.
The extra width and depth enables cabling to be routed with ease also helping to maintain bend-radius for fibre and copper cables and deeper equipment to be utilised. The strength required of the mounting posts means they are invariably not merely flat strips but actually a wider folded strip arranged around the corner of the rack.
Racks, especially two-post racks, are often secured to the floor or adjacent building structure so as not to fall over.
This is usually required by local building codes in seismic zones. According to Telcordia Technologies Generic Requirements document GRCORE, during an earthquake, telecommunications equipment is subjected to motions that can over-stress equipment framework, circuit boards, and connectors.
The amount of motion and resulting stress depends on the structural characteristics of the building and framework in which the equipment is contained, and the severity of the earthquake. Physical Protection, are available,  with Zone 4 representing the most demanding environment. Heavy equipment or equipment which is commonly accessed for servicing, for which attaching or detaching at all four corners simultaneously would pose a problem, is often not mounted directly onto the rack but instead is mounted via rails or slides.
A pair of rails is mounted directly onto the rack, and the equipment then slides into the rack along the rails, which support it. When in place, the equipment may also then be bolted to the rack. The rails may also be able to fully support the equipment in a position where it has been slid clear of the rack; this is useful for inspection or maintenance of equipment which will then be slid back into the rack. Slides or rails for computers and other data processing equipment such as disk arrays or routers often need to be purchased directly from the equipment manufacturer, as there is no standardization on such equipment’s thickness measurement from the side of the rack to the equipment or means for mounting to the rail.
A rails kit may include a cable management arm or CMAwhich folds the cables attached to the server and allows them to expand neatly when the server is slid out, without being disconnected. Computer servers designed for rack-mounting can include a number of extra features to make the server easy to use in the rack:.
When there is a large number of computers in a single rack, it is impractical for each one to have its own separate keyboard, mouse, and monitor. Since the mounting hole arrangement is vertically symmetric, it is possible to mount rack-mountable equipment upside-down. However, not all equipment is suitable for this type of mounting. For instance, most optical disc players will not work upside-down because the driving motor mechanism does not grip the disc.
A standard inch server rack cabinet is typically 42u in height, 19 inches Newer server rack cabinets come with adjustable mounting rails allowing the user to place the rails at a shorter depth if needed. There are a multitude of specialty server racks including soundproof server racks, air conditioned server racks, NEMA rated, seismic rated, open frame, narrow, and even miniature inch racks for smaller applications.
Racks carrying telecom equipment like routers and switches often have extra width to accommodate the many cables on the sides.
Four-post racks allow for mounting rails to support the equipment at the front and rear. Two-post racks provide two vertical posts. These posts are typically heavy gauge metal or extruded aluminum. Equipment can be mounted either close to its center of gravity to minimize load oec its front panelor via the equipment’s front panel holes.
Two-post racks are most often used for telecommunication installations. Road cases are typically made from polyvinyl chloride PVC laminated plywood sides, joined by extruded aluminum edging, steel corners, handles and latches. Larger cases typically have wheels for easy transport. Road case racks come in different heights based on the 1U standard and different depths.
Non-isolated cases simply mount inch mounting rails inside the case. To protect equipment from shock and vibration road rack cases use an inner and outer case. These cases can be isolated by thick layers of foam or may use spring-loaded shock mounting. Touring musicians, theatrical productions and sound and light companies use road case racks. Ina durable fiber reinforced plastic inch rackmount case was patented by ECS Composites and became widely used in military and commercial applications for electronic deployment and operation.
Portable rack cases using a rotary-molded polyethylene outer shell are a lower-cost alternative to the more durable ATA-approved case. These cases are marketed to musicians and entertainers for equipment 60279 subject to frequent transportation and rough handling. The polyethylene shell is not fiberglass reinforced and is not rigid.
The shape of small cases is maintained by the rack rails and the cover seal extrusions alone. Larger cases are further reinforced with additional plywood or sheet metal. The outer 602977 is frequently embossed in a self-mating pattern to combat the tendency for stacked cases to deform slightly creating a slope that encourages the upper case to slide off.
The cases typically use extruded aluminum bands at the ends of the body with tongue-and-groove mating to like bands for the covers. End covers are typically secured with either a simple draw latch or a rotary cam “butterfly” latch, named for the shape of the twist handle.
There is no standard for iecc and cooling of rack mounted equipment. A variety of airflow patterns can be found, including front intakes and rear exhausts, as well as side intakes and exhausts. Low-wattage devices may not employ active cooling, but use only passive thermal radiation and convection to dissipate heat. For rack mounted computer servers, devices generally intake air on the front and exhaust on the rear.
This prevents circular airflows where hot exhaust air is recirculated through an adjacent device and causes overheating. Although open-frame racks are the least expensive, they also idc air-cooled equipment to dust, lint, and other environmental contamination. An enclosed sealed cabinet with forced air fans permits air filtration to protect equipment from dust. Ied server rooms 6097 often group rack cabinets together so that racks on both sides of an aisle are either front-facing or rear-facing, which simplifies cooling by supplying cool air to the front of the racks and collecting hot air from the rear of the racks.
These aisles may themselves be enclosed into a cold air containment tunnel so that cooling air does not travel to other parts of the building where it is not needed or mixes with hot air, making it less efficient.
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Raised or false floor cooling in server rooms can serve a similar purpose; they permit cooling airflow to equipment through the underfloor space to the underside of enclosed rack cabinets. A difficulty with forced air fan cooling in rack equipment is that fans can fail due to age or dust. The fans themselves can be difficult to replace. In the case of network equipment, it may be necessary to unplug 50 or more cables from the device, remove the device from the rack, and then disassemble the device chassis to replace the fans.
However, some rack equipment has been designed to make fan replacement easy, using quick-change fan trays that can be accessed without removing ifc cabling or the device from the rack, and in some cases without turning off the device so that operation is uninterrupted during replacement.
A rack’s mounting fixture consists of two parallel metal strips also referred to as “posts” or “panel mounts” standing vertically. The posts are each 0. The posts have holes in them at regular intervals, with both posts matching, so that each hole is part of a horizontal pair with a center-to-center distance of The holes in the posts are arranged vertically in repeating sets of three, with center-to-center 602297 of 0.