The 2016 edition of NFPA 11 Standard for Low-, Medium-, and High-Expansion Foam is now available. Here are 8 important changes that are worth noting.
#1) Manufacturers are now required to publish acceptable ranges of density (or specific gravity), pH, refractive index, and viscosity for the foam concentrates that they produce. These values are intended to be used by laboratories to establish pass/fail criteria for annual quality testing. Because this information has not been consistently available in the past, laboratories have been required to make assumptions about the appropriate tolerances. To further support the measurement of foam quality, new definitions for “film formation” and “spreading coefficient” were also added.
#2) The suction inlet in an atmospheric concentrate storage tank must be located a minimum of 25.4 mm (1 in.) above the bottom of the tank. This creates a settling basin to reduce the risk of sediment entering the system. The volume of foam concentrate located below the inlet is not considered to be usable and cannot be counted as part of the minimum foam supply.
#3) The system piping section has been reorganized to clearly indicate separate requirements for foam concentrate and foam solution. The options for foam solution piping materials have been expanded to permit non-galvanized pipe, while ensuring compatibility of the pipe material with the foam solution.
#4) The allowance to provide seal-only protection for outdoor covered (internal) floating roof tanks has been extended to certain composite floating roofs that have been deemed to provide similar performance to metallic roofs. The specific roof features are considered adequate to resist burn through and/or submergence of the roof, in the event of a fire.
#5) Chapter 8 has been expanded to identify key components of system plans, including new details for hydraulic calculations and water supply graph sheets. The list of information to be included, as appropriate, has increased from 13 items to 33.
#6) Valves and hose connections must be installed to facilitate testing of proportioning equipment. Although certain acceptance and maintenance tests are required by Chapters 11 and 12, the standard did not previously include an installation requirement to provide a means of conducting these tests.
#7) The requirements for acceptance testing now include a water supply test and an operational test of control valves. A sample Material and Test Certificate was also added to Annex A to provide a means of documenting the acceptance test results.
#8) Descriptions of new foam proportioning test methods that do not require the discharge of foam concentrate were added to Annex D. Chapter 12 already supported alternative test methods, but specific test descriptions or procedures were not provided.
For a complete revision history of NFPA 11 or to read the 2016 edition for free, please visit the NFPA 11 Document Information Page at www.nfpa.org/11.