This handbook shall be used for the engineering design of new chemically-hardened military facilities. It provides information for the designer of the facility in the area of chemical/biological and mixed-munitions attack hardening of buildings. At the present this handbook is based upon design criteria developed and/or used by the U.S. military services and the private sector. The design criteria in this handbook will be revised or expanded as new information becomes available through experience and research or products and procedures. The contents include chemical threat considerations, and architectural, mechanical, and electrical design criteria unique to chemical warfare protection.