"Traditionally@ cellular foam products have been checked for load deflection by determining the load required to cause a 25% deflection. In automotive seating@ on the other hand@ the load deflection is checked by determining the thickness under constant force conditions to (a) indicate the initial softness of the seat cushion@ (b) measure how thick the seat cushion is under the average passenger load (a measurement of padding left for ""ride"" and seated height)@ and (c) determine a value to indicate resiliency. In this method these measurements are made by determining the thickness of the seat cushion under fixed loads of 4.5 N@ 110 N@ and 220 N with a 323 cm2 circular indentor foot."
SAE J815-2012 history
2012SAE J815-2012 Load Deflection Testing of Urethane Foams for Automotive Seating
2007SAE J815-2007 Load Deflection Testing of Urethane Foams for Automotive Seating
2002SAE J815-2002 Load Deflection Testing of Urethane Foams for Automotive Seating
2001SAE J815-2001 Load Deflection Testing of Urethane Foams for Automotive Seating
1998SAE J815-1998 Load Deflection Testing of Urethane Foams for Automotive Seating
1994SAE J815-1994 LOAD DEFLECTION TESTING OF URETHANE FOAMS FOR AUTOMOTIVE SEATING
1962SAE J815-1962 Load Deflection Testing of Urethane Foams for Automotive Seating