Corrosion resistant steels for cargo oil tanks
|Publication Date:||1 November 2016|
Scope and application
This programme is applicable for the approval of manufacturers of:
- corrosion resistant steels for cargo oil tanks (with designations RCU, RCB or RCW) as referred in the Society's rules and standards, e.g. DNVGL-RU-SHIP Pt.2 Ch.2 Sec.2 . It is supplementary the approval programme DNVGL-CP-0243. For a description of general requirements, conditions and procedures related to the approval, please refer to DNVGL-CP-0346. This programme shall be applied in combination with DNVGL-CP-0243 and DNVGL-CP-0346.
It is applicable for steel that will be used as alternative means of corrosion protection for cargo oil tanks as specified in the performance standard MSC.289(87) of Regulation 3-11, Part A-1, Chapter II-1 of the SOLAS Convention (Corrosion protection of cargo oil tanks of crude oil tankers). Corrosion resistant steels qualified by this approval document shall not be used for corrosion resistant applications in other areas of a vessel.
The approval is limited to the material grade for which approval tests are carried out, for each kind of product form (plates, strips/coil, sections etc.) and for each application areas of a cargo oil tank (RCU, RCB and RCW). Approval is limited to maximum tested thickness. Approval of one product form will not cover other product forms and vice-versa (e.g. plates will not cover sections). In addition to the above, the approval is limited to the manufacturing process specification including chemical composition specification, rolling parameters and heat treatment of the plate(s) subjected to approval testing, as well as to welding consumable type/brand and welding method.
Approval can be obtained for application in one of the following areas of a cargo oil tank:
a) lower surface of strength deck and surrounding structures (RCU)
b) upper surface of inner bottom plating and surrounding structures (RCB)
c) for both strength deck and inner bottom plating (RCW).
The approval is limited to the material grade for which approval tests are carried out, but certain grades may, subject to agreement with the Society, also cover other grades in the same steel type group provided these would be covered by the manufacturer specification.
Approval of manufacturer certificate in accordance with this programme is equivalent to the type approval certificate required by MSC.289(87) and IACS UI SC258.