The space planning process for central office switching, transmission, and power systems begins once the equipment need is forecast and the particular type of system is decided. This process is concerned with determining the kinds and quantities of the system equipment to meet ultimate forecast circuit requirements, devising a layout and growth plan for the determined equipment, and planning and coordinating the cable distribution, lighting, and cooling schemes associated with the equipment layout. The entire procedure of establishing a space utilization plan requires many iterations because of the large number of engineering aspects that must be examined in the decision-making process. To simplify, optimize, and streamline space planning for large equipment systems, various planning aids have been developed. We describe the general approach and rationale in developing two of the more fundamental space planning aids: office plan algorithms and office planning guidelines. Office plan algorithms allow a space planning engineer to translate long-range circuit forecasts into specific equipment frame requirements and their associated building space, cooling, and power needs. Office planning guidelines help the engineer to devise an efficient layout of the equipment in the building space, and to help plan and coordinate the cabling, lighting, and cooling schemes for the equipment layout. The general developmental approach of the space planning aids, and their usage benefits, are clarified relative to T1 offices that conform to the New Equipment-Building System (NEBS) standards.