Purchasing Guide for Wellhead & Christmas Tree ... - Stream Flo

Material ClassesMaterial ClassBody, Bonnet, End &Outlet ConnectionsMinimum Material RequirementsPressure-Controlling Parts,Stems & Mandrel HangersAA - General Service Carbon or Low-alloy Steel Carbon or Low-alloy SteelBB - General Service Carbon or Low-alloy Steel Stainless SteelCC - General Service Stainless Steel Stainless SteelDD - Sour Service a Carbon or Low-alloy Steel b Carbon or Low-alloy Steel bEE - Sour Service a Carbon or Low alloy Steel b Stainless Steel bFF - Sour Service a Stainless Steel Stainless Steel bHH - Sour Service a CRAs bcd CRAs bcdZZ - Sour Service User Defined User DefinedaAs defined by NACE MR0175/ISO 15156 in compliance with NACE MR0175/ISO 15156.bIn compliance with NACE MR0175/ISO 15156.cCRA required on retained fluid wetted surfaces only. CRA cladding of low alloy or stainless steel ispermitted.dCRA as defined in Clause 3 of this International Standard. NACE MR0175/ISO 15156 definition of CRAdoes not apply.API 6A Annex O: Material Class ZZNACE MR0175/ISO 15156 includes provisions for the qualification of materials for a specific sour serviceapplication which is outside the parameters defined in that standard by means of testing or documentedfield history. This can include MR0175/ISO 15156 or the use of materials not addressed in MR0175/ISO15156. For such sour service applications, equipment may be described and marked as Material Class ZZ.It is the responsibility of the purchaser to evaluate and determine the applicability of the documenteddata for the intended application. For material Class ZZ, the manufacturer shall meet materialspecifications supplied or approved by the purchaser and shall maintain traceable records to documentthe materials of construction, regardless of PSL.More NACE InformationMaterial Classes DD, EE, FF and HH require compliance to NACE MR0175 (ISO 15156) and responsibilityfor the choice rests with the purchaser.Examples of DesignationsClass FF-1.5 means:a) material class FFb) rated at 1.5 psia H 2S maximum allowable partial pressureClass NL means:a) where no H 2S limit is defined by NACE, NL shall be used for marking (i.e. DD-NL).8