توضیحات :
NFPA 11 – Standard for Low-, Medium-, and High-Expansion Foam
۲۰۲۱ Edition
This edition of NFPA 11, Standard for Low, Medium, and High-Expansion Foam, was prepared by the Technical Committee on Foam. It was issued by the Standards Council on November 2, 2020, with an effective date of November 22, 2020, and supersedes all previous editions.
This document has been amended by one or more Tentative Interim Amendments (TIAS) and٫or Errata. See “Codes & Standards” at www.nfpa.org for more information.
This edition of NFPA 11 was approved as an American National Standard on November 22, 2020.
Origin and Development of NFPA 11
NFPA committee activity in this field dates from 1921, when the Committee on Manufacturing Risks and Special Hazards prepared standards on foam as a section of the general Standard on Protection of Fire Hazards, Incident to the Use of Volatiles in Manufacturing Processes. Subsequently the standards were successively under the jurisdiction of the Committee on Manufacturing Hazards and the Committee on Special Extinguishing Systems, prior to the present committee organization. The present text supersedes the prior editions adopted in 1922, 1926, 1931, 1936, 1942, 1950, 1954, 1959, 1960, 1963, 1969, 1970, 1972, 1973, 1974, 1975, 1976, and 1978. It also supersedes the 1977 edition of NFPA 11 B.
The 1983 edition was completely rewritten to include all the material formerly contained in NFPA 11B, Standard on Synthetic and Combined Agent Systems. The standard was revised in 1988 and again in 1994 to state the requirements more clearly and to separate mandatory requirements from advisory text.
The standard was revised for the 1998 edition to include requirements for foam systems for marine applications and to provide guidance relating to the environmental impact of foam system discharges.
The 2002 edition was revised to address mixing of foam concentrates and to clarify requirements related to foam concentrate pumps. Requirements for medium- and high-expansion foam systems were included.
The 2005 edition was reorganized to provide the requirements for low-, medium-, and high- expansion foam. to better incorporate the requirements of NFPA 11A.
The 2010 edition added a new chapter to address compressed air foam systems. Unenforceable terms were removed to comply with the Manual of Style for NFPA Technical Committee Documents.
For the 2016 edition, the committee addressed several areas of concern. The piping requirements were reorganized and clarified, issues regarding acceptance criteria for annual foam concentrate testing were addressed, environmentally friendly methods of testing foam proportioners were recognized, and seal-only protection was permitted for composite roofs that meet specific criteria.
The 2021 edition contains multiple revisions to address the use of synthetic fluorine free foam (SFFF), including a new definition for SFFF. New definitions and explanatory annex material have been provided for cone roofs and external floating roofs. In Chapter 4, requirements that listed the types of foams permitted to be used on hydrocarbon fuels have been deleted, as the standard already requires foams to be listed for the flammable or combustible liquid they are protecting. Metric conversions throughout the standard have been updated as necessary to provide more usable numbers for metric users.
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