Hydrogen Induced Cracking (HIC) is a form of wet H2S (Hydrogen Sulfide) cracking caused by the blistering of a metal due to a high concentration of hydrogen. The blistering damage tends to form parallel to the surface and to the direction of hoop stress. 

ST conducts HIC as per and SOHIC as per NACE TM 0284


                                                                           ∑ (a x b)  

                          Crack Sensitivity Ratio, CSR= ------------- x 100%                 

                                                                             (W x T)


                                                                          ∑ a   

                          Crack Length Ratio,    CLR= -------- x 100%                 



                                                                            ∑ b   

                          Crack Thickness Ratio, CTR = ------ x 100%                 


                        Where; a= crack length

                                     b= crack thickness

                                     W= section width

                                     T = test specimen thickness.