NFPA 11 is a widely recognized US Standard for Low-, Medium-, and High-Expansion Fire Fighting Foam. It was introduced by the National Fire Protection Agency (NFPA). The most recent revision is NFPA 11: 2021. Let's delve into the key differences between this current version and the previous ones: 1. Scope and Coverage: - NFPA 11: 2021 continues to cover the design, installation, operation, testing, and maintenance of low-, medium-, and high-expansion foam systems for fire protection. - The criteria apply to fixed, semi-fixed, or portable systems for both interior and exterior hazards. 2. Annual Testing Requirements: - The current standard stipulates that both foam concentrates and foam proportioning systems should be tested at least annually. - Specifically, the foam concentrate induction rate of a proportioner must be within the specified range. 3. Inspection and Maintenance: - NFPA 11: 2021 mandates that all foam systems undergo thorough annual inspection and testing to ensure correct operation and full operating condition until the next inspection. 4. Foam Concentrate Inspection: - At least annually, an inspection must be conducted on foam concentrates and their storage containers to check for signs of excessive sludging or deterioration. - Samples of concentrates should be sent to the manufacturer or a qualified laboratory for quality condition testing. In summary, NFPA 11: 2021 emphasizes regular testing, inspection, and maintenance to ensure effective fire protection using foam systems.