This three-volume handbook is a reference for the planning andengineering 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 DoB fixed f acilities .Communications and data proceasing instal1 ations ine1 ude equipment rooms and s aces needing more precisely controlled environments than comfort s aces.Tie more limiting parameters within these rooms and spaces are estab cished 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.