BS MA 49:1986 download free.Summary and appllcation of car bon steel tubes for marine pipework systems.
1 Scope
BS MA 49 summarizes a series of carbon steel tubes suitable for marine pipework systems in terms of materials, size and thicknesses of tube together with limiting working conditions. Where necessary to meet regulatory bodies’ or classification societies’ rules, requirements additional to those in relevant British Standards are specified. Zinc coating and repair of defects are also covered.
BS MA 49 does not apply to tubes intended for use in the following applications.
a) Chemical cargo installations, which are subject to special material requirements to resist liquid or gaseous attack.
b) Low temperature installations where the minimum temperature is below — 50 °C.
c) High temperature installations where the maximum temperature is above 400 °C.
NOTE I For the purposes of this standard, the term “tube” has been used in accordance with international agreement. No difference is intended in meaning between “tube” and “pipe’, although idiomatic use prefers sometimes one and sometimes the other.
NOTE 2 The titles of the publications referred to in this standard arc listed on the inside back cover.
2 Definition
For the purposes of BS MA 49, the following definition applies.
surveyor
the representative of the marine regulatory body and/or classification society concerned
3 Classification
The design pressure/temperature ratings, which vary according to the type of system on which a tube is to be used, shall be grouped for the purposes of this standard as follows:
class 1: high pressure/temperature applications and low temperature
applications (down to — 50 °C);
class II: intermediate pressure/temperature; class III: low pressure/temperature (above 0 °C).
4 Materials
Materials for tubes shall be in accordance with BS 1387, BS 3601, BS 3602 or BS 3603, as appropriate.
A summary of the steel tube materials covered by BS MA 49 appropriate to the piping classes is given in Table 1. The code letters defining the method of manufacture (see Appendix B). and the available size ranges are also given.
NOTE Comparable American and German specifications arc given in Appendix A.
5 Tube dimensions
5.1 Tube dimensions shall be specified by the details shown in Table 2 and Table 3 (which are extracted from BS 3600). Tubes in Table 3 shall be specified by their outside diameter and thickness.
NOTE It is common practice in standards for various types of joints, fittings and flanges, to designate the tube by the nominal size. The nominal size is a numerical designation of size which is common to all components in a piping system other than components designated by outside diameter. It is a convenient round number for reference purposes and is normally only loosely related to manufacturing dimensions.
5.2 The required design thickness of the pipe shall be calculated in accordance with the relevant regulatory body rules for pressure pipes and a standard thickness equal to or greater than the calculated thickness selected from Table 2 or Table 3. The heavy line in Table 2 and the lower limit heavy line in Table 3 represent the minimum acceptable pipe thicknesses specified in regulatory bodies’ rules for pressure pipes in general.
6 Application
The application ofcarbon steel tubes in ships’ piping systems shall be in accordance with Table 4 appropriate to the class of pipe, material specification and piping system.
7 Product approval
7.1 General
Carbon steel tubes intended for applications in accordance with clause 6. for use in the construction or repair of ships’ pipelines, shall comply with 7.2.
7.2 Classes I, II and III
Tubes for class I and class II applications shall be manufactured at approved works, shall comply with BS 3602 (class I), BS 3603 (class I) and BS 3601 (class TI), but shall be surveyed and tested in accordance with regulatory body rule requirements. Tubes for class III applications shall be manufactured and tested in accordance with the requirements of BS 3601 or BS 1387, and a manufacturer’s certificate shall be provided for each consignment of material.
8 Additional protection
8.1 Hot dip galvanized tubes are available to the
13S 1387 specification and reference shall be made to
that standard for details.
8.2 Where steel tubes are required to be hot-dip galvanized internally and externally after all fabrication is completed. this shall be in accordance with BS 729 except that for sea-water services the minimum mass of coating shall be 610 g/m2 for all pipe thicknesses (see BS MA 18).
NOTE 1 Attention is drawn to the rules of regulatory bodies’ concerning the use of hot dip galvanized tubes where water speeds exceed 3 mIs and also to the restrictions placed on hot dip galvanized tubes in refrigeration installations.
NOTE 2 Non-metallic methods of tube protection arc available, but service experience to date is inadequate. See, however, CP 3003.
8.3 The renovation of damaged areas of hot dip galvanized coatings shall be carried out in accordance with Appendix D of BS 729: 1971.