Polyurethane Foam Test Methods
Different countries use different test methods and some tests are specific to the application.
The following gives a comprehensive overview of the different tests.
DENSITY
is defined as the mass per unit volume in air. Density is measured by dividing the weight of a sample by its volume.
Normally recorded in Kg/M³ however the USA record their's in Lb/ft³ (to convert Lb/ft³ to Kg/M³, multiply the Lbs * 16)
Weight
Kg
Density
Kg/M³ = -------------
Volume
M³
Some test methods used: - ASTM D3574-91, BS4443, Din53420, ISO 845.
HARDNESS
CLD (compression
load deflection)
is defined as the force required to compress a 100*100*50mm piece
of foam with a 200mm dia compression plate. The foam is
compressed three times to 70% and then after the third compression
readings are taken at 60%, 40% and 25%.
Recorded in kPa
Some test methods are: - DIN 53577, ISO 3386/1
ILD (indentation
load deflection UK)
is defined as the force required to compress a 380*380*50mm piece
of foam by 40% with a 200mm dia compression plate.
Recorded in Newtons (N)
Some test methods are: - BS4443 pt 2 method 7, ISO 2439 B
ILD (indentation
load deflection USA)
is defined as the force required to compress a 18*18*4inch piece of
foam by 25% with a 8inch dia compression plate.
Recorded in lbs or psi
Some test methods are: - ASTM 3574-91
TENSILE STRENGTH & ELONGATION
Tensile Strength
is defined as the maximum force reached at the point of
rupture
Recorded in kPa
Elongation
is defined as the measurement of elongation at the rupture
point
Recorded in %
Some Test methods: - ISO 1798
PPI (reticulated foams)
PPI is defined as the number of pores per inch. Originally calculated by comparing the pressure drop of a 12 inch diameter 1" thick sample of foam against a perforated steel sheet of the same size. Since then more technical methods have been used but still do not compare to visual comparisons.
