Level 3 Carbon Footprints require both a bill of materials, process model and may require a run of GreenInsight to determine organisational overheads. Then all of the inputs have level 2 carbon footprints calculated up to a value of 98% of the expected total carbon footprint.
A Level 3 Carbon Footprint is for high volume products where accurate measurement of the inputs is the first step towards a targeted carbon reduction program.