This chapter describes the methodology used in EPA’s Waste Reduction Model (WARM) to estimate streamlined life‐cycle greenhouse gas (GHG) emission factors for asphalt shingles beginning at the waste generation reference point.1 The WARM GHG emission factors are used to compare the net emissions associated with asphalt shingles in the following four waste management alternatives: source reduction, recycling, combustion and landfilling. Exhibit 1 shows the general outline of materials management pathways for asphalt shingles in WARM. For background information on the general purpose and function of WARM emission factors, see the Introduction & Overview chapter. For more information on Source Reduction, Recycling, Combustion and Landfilling, see the chapters devoted to those processes.