as well as implementation of fire prevention programmes in operations. Smoke detectors are usually installed to provide early warning of a developing fire by detecting particles generated by smouldering components prior to the development of flame. This allows investigation, interruption of power, and manual fire suppression using hand held fire extinguishers before the fire grows to a large size. A fire sprinkler system is often provided to control a full scale fire if it develops. Clean agent fire suppression gaseous systems are sometimes installed to suppress a fire earlier than the fire sprinkler system. Passive fire protection elements include the installation of fire walls around the space, so a fire can be restricted to a portion of the facility for a limited time in the event of the failure of the active fire protection systems, or if they are not installed. 19-inch racks for data equipment and servers, 23-inch racks for telecommunications equipment Cabinets and cages for physical access control over tenants' equipment. Depending on one's needs a cabinet can house individual or multiple racks. Overhead or underfloor cable rack (tray) and fibreguide, power cables usually on separate rack from data Air conditioning is used to control the temperature and humidity in the space. ASHRAE recommends a temperature range and humidity range for optimal electronic equipment conditions versus environmental issues. The electrical power used by the electronic equipment is converted to heat, which is rejected to the ambient air in the data centre space. Unless the heat is removed, the ambient temperature will rise, resulting in electronic equipment malfunction. By controlling the space air temperature, the server components at the board level are kept within the manufacturer's specified temperature and humidity range. Air conditioning systems help keep equipment space humidity within acceptable parameters by cooling the return space air below the dew point. Too much humidity and water may begin to condense on internal components. In case of a dry atmosphere, ancillary humidification systems may add water vapour to the space if the humidity is too low, to avoid static electricity discharge problems which may damage components. Low-impedance electrical ground Few, if any, windows Colocation data centres are often audited to prove that they attain certain standards and levels of reliability; the most commonly seen systems are SSAE 16 SOC 1 Type I and Type II (formerly SAS 70 Type I and Type II) and the tier system by the