Test by ASTM
Test Consumer Product Safety Commission's Test 16 CFR 1615/1616 and
ASTM Test D4723
Title Flammability of Children's Polyester Sleepwear
Procedure: Test fabrics submitted by Carter Manufacturing © were washed with various detergents, dried and exposed to open flame for 50 cycles. Results were measured by char length at each cycle.
Results: Charlie's Soap continued to improve the flame retardant properties after each washing to the point where the fabric would not catch fire at all. No other detergent tested improved the flame retardant properties of children's sleepwear at all.