"INTRODUCTION The code and commentary includes excerpts from ACI 318-02 that are pertinent to ACI 350. The commentary discusses some of the considerations of Committee ACI 350 in developing ""Code Requirements for Environmental Engineering Concrete Structures (ACI 350-06)@"" hereinafter called the code. Emphasis is given to the explanation of provisions that may be unfamiliar to users of the standard. Comments on specific provisions are made under the corresponding chapter and section numbers of the code and commentary. This commentary is not intended to provide a complete historical background concerning the development of the code@ nor is it intended to provide a detailed summary of the studies and research data reviewed by the committee in formulating the provisions of the code. However@ references to some of the research data are provided for those who wish to study the background material in depth. As the name implies@ ""Code Requirements for Environmental Engineering Concrete Structures"" may be used as part of a legally adopted code and@ as such@ must differ in form and substance from documents that provide detailed specifications@ recommended practice@ complete design procedures@ or design aids. The code is intended to cover environmental engineering concrete structures@ but is not intended to supersede ASTM standards for precast structures. Requirements more stringent than the code provisions may be desirable for unusual structures. This code and this commentary cannot replace sound engineering knowledge@ experience@ and judgment. A code for design and construction states the minimum requirements necessary to provide for public health and safety. ACI 350 is based on this principle. For any structure@ the owner or the structural designer may require the quality of materials and construction to be higher than the minimum requirements necessary to provide serviceability and to protect the public as stated in the code. Lower standards@ however@ are not permitted. ACI 350 has no legal status unless it is adopted by government bodies having the power to regulate building design and construction. Where the code has not been adopted@ it may serve as a reference to good practice. The code provides a means of establishing minimum standards for acceptance of design and construction by a legally appointed building official or his designated representatives. The code and commentary are not intended for use in settling disputes between the owner@ engineer@ architect@ contractor@ or their agents@ subcontractors@ material suppliers@ or testing agencies. Therefore@ the code cannot define the contract responsibility of each of the parties in usual construction. General references requiring compliance with ACI 350 in the job specifications should be avoided@ since the contractor is rarely in a position to accept responsibility for design details or construction requirements that depend on a detailed knowledge of the design. Generally@ the drawings@ specifications@ and contract documents should contain all of the necessary requirements to ensure compliance with the code. In part@ this can be accomplished by reference to specific code sections in the job specifications. Other ACI publications@ such as ACI 301@ ""Specifications for Structural Concrete@"" are written specifically for use as contract documents for construction. Committee 350 recognizes the desirability of standards of performance for individual parties involved in the contract documents. Available for this purpose are the certification programs of the American Concrete Institute@ the plant certification programs of the Precast/Prestressed Concrete Institute@ the National Ready Mixed Concrete Association@ and the qualification standards of the American Society of Concrete Constructors. Also available are ""Standard Specification for Agencies Engaged in Construction Inspection and/or Testing"" (ASTM E 329) and ""Standard Practice for Laboratories Testing Concrete and Concrete Aggregates for Use in Construction and Criteria for Laboratory Evaluation"" (ASTM C 1077)."