▁methods . ▁▁ 3 . ▁EP DM ▁refers ▁to ▁Eth yl ene ▁Pro py l ene ▁Mon omer , ▁a ▁firm , ▁yet ▁flexible , ▁rub ber ▁material . ▁▁ 4 . ▁ATP ▁refers ▁to ▁Ali ph atic ▁Th erm op last ic ▁Poly ure th ane , ▁a ▁firm , ▁yet ▁flexible , ▁pl astic ▁in ▁which ▁sphere - like ▁particles ▁are ▁chem ically ▁bond ed ▁to ▁a ▁color - fast ▁binding ▁material . ▁▁ 5 . ▁When ▁properly ▁installed ▁with ▁a ▁ 6 - in ▁depth . ▁▁ 6 . ▁Opt im isation ▁of ▁the ▁Sho ck ▁Att enu ation ▁Properties ▁of ▁Play ground ▁Sur faces ▁ ▁Saf ety ▁In ▁the ▁United ▁States , ▁play ground - related ▁inj uries ▁send ▁ 2 0 0 , 0 0 0 ▁children ▁to ▁an ▁emer gency ▁room ▁every ▁year . ▁If ▁vis its ▁to ▁do ctors ▁are ▁included , ▁the ▁figure ▁r ises ▁to ▁ 5 0 0 , 0 0 0 ▁inj uries , ▁according ▁to ▁the ▁American ▁Academy ▁of ▁Orth op edic ▁Sur ge ons . ▁More ▁than ▁half ▁of ▁these ▁inj uries ▁result ▁from ▁falls ▁to ▁a ▁play ground ▁surface ▁that ▁can ▁cause ▁f ract ures , ▁conc uss ions , ▁dis loc ations , ▁and ▁internal ▁inj uries . ▁Rec ogn izing ▁these ▁facts , ▁many ▁organizations , ▁including ▁the ▁Cons umer ▁Product ▁Saf ety ▁Commission , ▁have ▁issued ▁gu idel ines ▁and ▁standards ▁for ▁play ground ▁surfaces . ▁ ▁Test ing ▁methods ▁and ▁standards ▁A ST M ▁International