NFPA 17AStandard for Wet Chemical Extinguishing Systems1998 EditionCopyright 1998 NFPA, All Rights ReservedThis edition of NFPA 17A, Standard for Wet Chemical Extinguishing Systems, was prepared by the Technical Committee on Dry and Wet Chemical Extinguishing Systems and acted on by the National Fire Protection Association, Inc., at its Fall Meeting held November 17-19, 1997, in Kansas City, MO. It was issued by the Standards Council on January 16, 1998, with an effective date of February 6, 1998, and supersedes all previous editions.Changes other than editorial are indicated by a vertical rule in the margin of the pages on which they appear. These lines are included as an aid to the user in identifying changes from the previous edition.This edition of NFPA 17A was approved as an American National Standard on March 31, 1998.Origin and Development of NFPA 17AThe Dry Chemical Extinguishing Systems Committee was activated in 1952. On April 6, 1983, the Standards Council received a request to assign the subject of wet chemical extinguishing systems to the appropriate committee. Listed systems had been available for some time. After the Foam Committee declined the request, the Dry Chemical Committee was asked to assume responsibility for the project. In May 1983, the Dry Chemical Extinguishing Systems Committee voted to accept the assignment and requested that the Standards Council expand the Committee Scope to include the new topic. The Committee also requested that the new document be identified as NFPA 17A, Standard for Wet Chemical Extinguishing Systems. A subcommittee met in June 1983 to develop the text. In November 1984, the Council approved a request to change the name of the Committee to the Committee on Dry and Wet Chemical Extinguishing Systems. The 1990 edition was a partial revision of the 1986 edition.The 1998 edition of this standard has been revised to clarify the requirements for protection of unclosable openings and equipment shutdown.Technical Committee on Dry and Wet Chemical Extinguishing SystemsEdward D. Leedy, ChairIndustrial Risk Insurers, IL IJohn H. Lawlor, SecretaryKeystone Fire Protection Co., PA IMRep. Natl Assn. of Fire Equipment DistributorsPaul E. Buchhofer, Building Inspection Underwriters, Inc., PA EWilliam M. Carey, Underwriters Laboratories Inc., IL RTJohn E. Cribben, Maryland Casualty Co., MD IRep. American Insurance Services Group, Inc.Samuel S. Dannaway, S. S. Dannaway Assoc. Inc., HI SEJack K. Dick, Heiser Inc., NY MAlan L. Hall, Loss Prevention Consultants, Inc., IL SEThomas J. Hard, T. J. Hard Cos., OH IMEdward J. Kaminski, Schirmer Engr Corp., IL SERobert Kasiski, Factory Mutual Research Corp., MA IJoseph N. Knapp, McDonalds Corp., IL URep. Natl Restaurant Assn.George A. Krabbe, Automatic Suppression Systems Inc., IL IMRep. Fire Suppression Systems Assn.Roland J. Land, Risk Control Consultants, LLC, NJ SEMichael P. McGreal, Firedyne Engr, PC, IL SEJ. R. Nerat, Fire Protection Specialist Inc., MI SEWilliam D. Shipley, Ansul Inc., WI MRichard A. Shiraishi, Kemper Natl Insurance Cos., CA IDesmond R. Todd, Levitt-Safety Ltd, Ontario, Canada MRep. Fire Equipment Mfrs. Inst. of CanadaWilliam Vegso, Wells Fargo/Pyro Technologies Inc., NJ MCraig Voelkert, Amerex Corp., AL MSteven E. Younis, Conceptual Engr Group, Inc., MD SEAlternatesSalvatore A. Chines, Industrial Risk Insurers, CT I(Alt. to E. D. Leedy)Anthony W. Flacco, Kemper Natl Insurance Cos., PA I(Alt. to R. A. Shiraishi)Stephen D. Healy, Kidde-Fenwal, MA M(Voting Alt.)William Klingenmaier, Ansul Inc., WI M(Alt to W. D. Shipley)Norbert W. Makowka, Natl Assn. of Fire Equipment Distributors, IL IM(Alt. to J. H. Lawlor)Dale Traub, AON Risk Services, Inc., NY I(Alt. to R. J. Land)Charles F. Willms, Fire Suppression Systems Assn., NC M(Alt. to G. A. Krabbe)Kenneth W. Zastrow, Underwriters Laboratories Inc., IL RT(Alt. to W. M. Carey)NonvotingWalter M. Haessler, Desert Hot Springs, CA(Member Emeritus)David R. Hague, NFPA Staff LiaisonThis list represents the membership at the time the Committee was balloted on the text of this edition. Since that time, changes in the membership may have occurred. A key to classifications is found at the back of this document.NOTE: Membership on a committee shall not in and of itself constitute an endorsement of the Association or any document developed by the committee on which the member serves.Committee Scope: This Committee shall have primary responsibility for documents on the design, installation, operation, testing, maintenance, and use of dry and wet chemical extinguishing systems for fire protection.NFPA 17Standard forWet Chemical Extinguishing Systems1998 EditionNOTICE: An asterisk (*) following the number or letter designating a paragraph indicates that explanatory material o