MIL-HDBK-411B VOL I

Abstract

This three-volume handbook is a reference for the planning and engineering of power and environmental control systems for fixed Department of Defense (DoD) communications, data processing, and information systems facilities. The engineering concepts contained herein should be selectively applied to the power and environmental elements of DoD fixed facilities. DoD communications and data processing installations include equipment rooms and spaces needing. more precisely controlled environments than comfort spaces. The more limiting parameters within these rooms and spaces are established specifically for the equipment being used. Outside these specially designed areas, where PCs and other electronic office equipment are used, the environment is the responsibility of the user. Power protection or conditioning for this equipment should follow the guidance provided in volume II. Environmental control of this space should follow the guidance contained in volume III. Volume I addresses these subjects in general terms for the planner, manager, or executive. Volume II addresses power system engineering considerations. Volume III addresses environmental control system engineering considerations. <br>This handbook applies to and discusses the following topics: <br>a. Mission requirements. <br>b. Power requirements and characteristics. <br>c. Power disturbances and distribution. <br>d. Power conversion, conditioning, and regulation. <br>e. Power system monitoring and control. <br>f. Construction design considerations. <br>g. Environmental considerations. <br>h. Auxiliary and alternate power systems. <br>i. Electromagnetic interference/electromagnetic compatibility (EMI/EMC). <br>j. Special considerations for computer-based equipment. <br>This handbook is intended to assist in selecting and planning power and environmental control systems to be installed or upgraded at DoD communications-electronics facilities and computer-based facilities. It is applicable to the engineering effort during initial establishment of a facility or during upgrade of an existing facility. This handbook introduces practices and procedures that should be considered during the engineering design effort. This guidance does not direct that any of these control systems be employed at any given facility. Further, this guidance is not to be used solely as 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 lists (QPLs). OSHA regulations state that employees shall not be required to work in surroundings or under working conditions which are unsanitary, hazardous, or dangerous to their health and safety. Employers are required to initiate and maintain programs which 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. Investigation of confined-space injuries and fatalities indicate that workers generally do not realize they are working in a confined space with unforeseen hazards. The studies show that testing and monitoring of the atmosphere are often not performed, and rescue procedures are seldom planned. <br>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." <br>Safety procedures should be established for electronic equipment employing high voltages or radiating high-energy fields. Safety requirements have been established in individual military department documents that should be reviewed prior to designing systems in accordance with guidance contained herein. <br>Remember the four rules: <br>a. Ground everything that can accidentally become energized. <br>b. Keep electricity separate from equipment not to be electrified. <br>c. Keep heat and sparks from electrical conductors and equipment, thereby preventing a fire or triggering an explosion. <br>d. Do not assume safety - Electrical equipment is dangerous until proven safe. <br>Personnel safety concerns are expressed throughout this handbook in paragraphs that are risk-specific, such as: hazardous gas control, electromagnetic radiation safety, and equipment grounding. <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 and environmental control systems at DoD fixed communications and related automatic data processing facilities. <br>