The purpose of this standard is to describe four methods for determining the hardness of elastomers, expressed in international degrees of elastomer hardness (IRHD), measured on specimens or articles with flat surfaces, namely, Method N - Normal test Method H - Test for high hardness Method L - Test for low hardness Method M - Micro-test, and four methods for determining apparent hardness, measured on specimens or articles with curved surfaces, using methods N, H, L and M respectively , viz. CN,CH,CL and CM Methods The methods differ mainly by the diameter of the indenter sphere and by the value of the penetration force, which are chosen depending on the particular application. The field of application of each method is indicated in Figure 1. Method N The normal hardness test is the appropriate method for specimens with a thickness greater than 4 mm and is preferably used for elastomers whose hardness is between 35 and 85 IRHD. but it can be used for those with a hardness between 30 and 95 IRHD.