NFPA 11 is an internationally recognized US Standard for Low-, Medium-, and High-Expansion Fire Fighting Foam. The standard, introduced by the National Fire Protection Agency (NFPA), provides guidelines for the design, installation, operation, testing, and maintenance of foam systems used in fire protection. The current revision is NFPA 11: 2021. Here are some key points differentiating the current version from the previous one: 1. Scope and Coverage: - NFPA 11: 2021 covers low-, medium-, and high-expansion foam systems, addressing both interior and exterior hazards. - The previous version may have had different scope limitations or requirements. 2. Testing Requirements: - NFPA 11: 2021 stipulates that both foam concentrates and foam proportioning systems should be tested at least annually. - The previous version likely had different testing criteria. 3. Inspection and Maintenance: - NFPA 11: 2021 mandates thorough annual inspections and tests to ensure correct system operation. - The goal is to maintain the system in full operating condition until the next inspection. - The previous version might have had different inspection and maintenance guidelines. 4. Foam Concentrate Inspection: - NFPA 11: 2021 requires annual inspections of foam concentrates and their storage containers for signs of excessive sludging or deterioration. - Samples of concentrates must be sent for quality condition testing. - The previous version may not have had such specific requirements.