PVC (Polyvinyl chloride) is extracted from the polymerization of vinyl chloride monomer. We can classify PVC into two large groups, rigid PVC and flexible PVC.

Rigid: used for the construction of tubes, pipes, containers, tool accessories, parts of parts, blinds, windows, etc.
Flexible: Corrugated tube, traffic signs as cones. irrigation hoses, curtains for refrigerators, footwear, medicine, etc.

This material begins to soften at 80 ° C and melt at 140 ° C. Thanks to these and other properties, PVC is a recyclable material.

Among the main characteristics of PVC we find:

• Different degree of hardness.
• Waterproof.
• It does not corrode.
• It is moldable if it is subjected to high temperatures.
• Good electrical insulator.
• It is a very resistant material.
• Stable and inert.
• Good mechanical and impact resistance.
• High resistance to abrasion.
• Strong and lightweight.
• Good thermal insulation.
• It is odorless, tasteless and harmless.

A rack is a metal support designed to house electronic, computer and communications equipment. The measures for the width are normalized to be compatible with most equipment manufacturers. They are also called racks, cabinets, cabinets or closets. Each column has holes at regular intervals called U rack units (Pictured: 4) grouped in threes. The height (Pictured:5) of the racks is standardized and external dimensions of 200 mm by 200 mm. Being normal that from 4U to 46/47U height width types (Pictured: 7). Standard 600 mm or 800 mm Types of background (Pictured: 6) The depth of the frame is not standardized, as this flexibility is granted (Pictured: 8) to the equipment. The most common are: - 450 mm - 600 mm - 800 mm - 900 mm - 1000 mm - 1200 mm Type 19-inch rack can find various types of 19-inch rack. Rack Mural (Pictured: 2): Used to accommodate electronic network. They are the smallest and are anchored to wall. Rack Pie (Pictured: 1): They are used primarily for servers, UPS and network electronics. Open Rack (Pictured: 3): Open Rack Racks are available only modelsstructure, eliminating doors and other accessories.

There are several cabinet heights according to the needs of the installation, this height can be measured in rack units (U).

Each rack unit or U is the distance between each horizontal separation to place the different accessories inside the rack. This distance is 1.75 inches that is equal to 4.4445 cm high.

For example, if we say that a rack is 8U we will understand that it has 8 units to install device orAccessories of 4.44 cm in height.

Normally these accessories, like trays, guides, strips, etc. Occupy a unit of U (1U), but we can find that other devices or accessories occupy more units, for example can be a rack box to install a PC, a UPS, etc. It can be said that there is also a half unit of U (0.5U), in this case, two units could be installed in a rack unit.

As far as I knowEndo the units of rack that occupy the devices that we are going to install we will know the height that we need for our rack.

The size of the rack unit (U) is based on the standard specification for racks defined in EIA-310.