MIL-HDBK-411B VOL II

Abstract

Volume II of this three-volume handbook provides power system guidance for fixed Department of Defense (DoD) communications, data processing, and information system facilities. The engineering concepts contained in this volume should be selectively applied to the power elements at DoD fixed facilities. <br>This volume also presents power considerations to use in the engineering of power systems where equipment has been added that is external to a space specifically designed for communications or automatic data processing equipment. Power protection or conditioning for this equipment should follow the guidance provided in this volume. To ensure that environmental control systems for this equipment meet the required parameters, Volume III of this handbook should be consulted. <br>Volume I addresses these subjects in general terms for the manager or executive. Volume II addresses power system engineering considerations. Volume III addresses environmental control system engineering considerations. <br>Volume II of this handbook applies to and discusses the following topics: <br>a. Power requirements and characteristics. <br>b. Power disturbances, protection, and distribution. <br>c. Power conversion, conditioning, and regulation. <br>d. Power system monitoring and control. <br>e. Auxiliary and alternative power systems. <br>f. Electromagnetic interference/electromagnetic compatibility (EMI/EMC). <br>g. Special considerations for computer-based equipment. <br>This handbook can assist in selecting or planning power systems to be installed or upgraded at DoD communications-electronics facilities and related information processing facilities. It applies to engineering during the initial establishment of a facility, or during the upgrade of an existing facility. In addition, this guidance can assist in the engineering of power systems when automation requires using information processing equipment (computers and computer-controlled equipment). This handbook introduces practices and procedures that should be considered during the engineering design phase. This guidance is not to be interpreted as directing that any or all of these control systems should be used at any given facility. Further, it is not to be used solely as a justification for retrofit of existing DoD communications, data processing, and information systems facilities. <br>Occupational Safety and Health Administration (OSHA) regulations require a safe work place at all times. Although OSHA does not approve specific tools or products, there are Federal specifications for safety tools and they are listed in the appropriate qualified products list (QPL). <br>OSHA regulations state that no employee shall be required to work in surroundings or under working conditions that are unsanitary, hazardous, or dangerous to health or safety. Employers are required to initiate and maintain programs that comply with this requirement. These programs include inspections of job sites, materials, and equipment. They also ascertain that the use and operation of equipment or machinery is by qualified employees. <br>The National Institute for Occupational Safety and Health (NIOSH) estimates that millions of workers may be exposed to hazards in confined spaces each year. NIOSH's definition of a confined space is: "a space which by design has limited openings for entry and exit, unfavorable natural ventilation which could contain or produce dangerous air contaminants, and which is not intended for continuous employee occupancy." Investigations of confined-space injuries and fatalities indicate that workers usually do not recognize that they are working in a confined space and may encounter unforseen hazards. <br>Electrical and electronic equipment normally utilize high voltages and, in some installations, high-energy radiation fields. Safety requirements have been established in individual service documentation that should be reviewed prior to engineering systems in accordance with guidance contained in this volume. <br>Remember four safety rules: <br>a. Ground everything that might accidentally become energized. <br>b. Keep electricity separated from anything that is not to be electrified. <br>c. Keep heat and sparks (from electrical conductors and equipment) from starting a fire or triggering an explosion. <br>d. Do not assume electronic equipment is safe. Electrical equipment is dangerous until made or proven safe. <b><u>Intended Use:</u></b> The purpose of this handbook is to provide basic guidance to managers and engineers of the military departments and agencies in the design and installation of power systems at DoD fixed communications and related automatic data processing facilities. <br>