NFPA®557 Standard for Determination of Fire Loads for Use in Structural Fire Protection Design, 2020 Edition Chapter 1 Administration 1.1 Scope. 1.2 Purpose. 1.3 Application. 1.4 Equivalency. 1.5 Units and Formulas. 1.6 Approved Qualifications. Chapter 2 Referenced Publications 2.1 General. 2.2 NFPA Publications. 2.3 Other Publications. 2.4 References for Extracts in Mandatory Sections. Chapter 3 Definitions 3.1 General. 3.2 NFPA Official Definitions. 3.3 General Definitions. Chapter 4 Design Fundamentals 4.1 Methodology. 4.2 Fire Load. 4.3 Statistical Distribution of Fire Load. 4.4 Frequency of Fire Initiations. 4.5 Effectiveness of Fire Protection Features. 4.6 Combustibility of Materials. Chapter 5 Development of Fire Loads 5.1 Types of Fire Loads. 5.2 Defining the Compartment. 5.3 Distributed Fire Loads. 5.4 Localized Fire Loads.5.5 Frequency of Structurally Significant Fires. 5.6 Approvals and Limitations. 5.7 Application of the Frequencies of Structurally Significant Fires to Occupancies. Chapter 6 Occupancy-Based Fire Load Density 6.1 Fire Load Density. 6.2 Design Fire Load Density. Chapter 7 Survey Method-Based Fire Load Density 7.1 Fire Load Density 7.2 Fire Load. 7.3 Heats of Combustion. 7.4 Methodology and Limitations. Chapter 8 Documentation, Inspection, and Maintenance 8.1 Documented Fire Load. 8.2 Change in Occupancy. 8.3 Repairs. 8.4 Formal Review. Annex A Explanatory Material Annex B Summary of Occupancy Based Fuel and Fire Load Survey Data Annex C Guidance for Fuel or Fire Load Surveys (Special Facility and Occupancy Based) Annex D Analyses of Structurally Significant Fires in Buildings with Selected Characteristics Annex E Informational References