Committees responsible for this British Standard

The preparation of this British Standard was entrusted by the General Mechanical Engineering Standards Committee (GME/-) to Technical Committee GME/4 upon which the following bodies were represented:

Amalgamated Union of Engineering Workers (Technical and Supervisory Section)

British Paper and Board Industry Federation (PIF)

British Railways Board

British Standards Society

Drawing Office Material Manufacturers’ and Dealers’ Association

Electricity Supply Industry in England and Wales

Electronic Engineering Association

Engineering Equipment and Materials Users’ Association Gauge and Tool Makers’ Association

Institution of Electrical Engineers

Institution of Electronic and Radio Engineers

Institution of Engineering Designers

Institution of Mechanical Engineers

Institution of Production Engineers

Ministry of Defence

Society of British Aerospace Companies Ltd

Society of Motor Manufacturers and Traders Limited

Telecommunication Engineering and Manufacturing Association

United Kingdom Atomic Energy Authority

This British Standard, having been prepared under the direction of the General Mechanical Engineering Standards Committee, was published under the authority of the Board of BSI and comes into effect on 29 April 1988

The following BSI references relate to the work on this standard:

Committee reference GME/4 Draft for comment 85/79731 DC

Foreword

This part of BS 5070 has been prepared under the direction of the General Mechanical Engineering Standards Committee and, together with Part 1 and Part 2 ^*, supersedes BS 5070:1974 which is now withdrawn. The 1974 edition set out recommendations for drawing practice to be followed in preparing engineering diagrams in all fields of engineering with a view to securing uniformity between one drawing office and another in the same industry. It also aimed to increase uniformity between one field of engineering and another in the basic principles involved and in the designations for different types of diagram.

Attention is drawn to BS 5070 being a companion standard to BS 308; the latter covers engineering drawing practice used in a wide range of engineering disciplines. Commonly, as a diagram can be called a “drawing” and a drawing can be called a “diagram”, it is useful to summarize the difference in the scopes of these standards. BS 308 covers what are commonly accepted to be drawings that define shape, size and form. BS 5070 covers the drawing of diagrams that are normally associated with flow of one sort or another and which relate components (usually indicated by symbols) functionally one to another by the use of lines, but do not depict their shape, size or form; neither do they in general indicate physical connections or locations.

From experience with the 1974 edition it was decided that for this first revision, whilst bearing in mind the long term aim of uniformity of conventions, there was a need for more comprehensive treatment of the varying requirements of differing industries and for more careful attention to their presentation. BS 5070 is therefore now revised in parts by which the practice and conventions of several disciplines and industries are collected into three groups. Part 1 covers general principles common to all subsequent parts, which in turn deal particularly with electrotechnology; mechanical and fluid flow and systems; and logic.

This standard gives recommendations for the drawing of engineering diagrams using the symbols given in relevant British Standards. It does not itself originate symbols. The diagrams in this standard contain symbols as they appear in the particular standards current at the time this publication was prepared. However, although every effort has been made to ensure that correct and current symbols have been used, it has to be recognized that the particular symbols standards are themselves subject to periodic review. It is therefore stressed that the relevant symbols standards, and not this standard, have to be consulted to obtain definitive symbols.

The recommendations of this standard have been established having regard to the requirements of microfilming. Diagrams prepared in accordance with this standard should be suitable for microfilming and reduced-size reproduction techniques.

During the course of this revision particular attention has been paid to developments in computer aided machine draughting and it has been established that such machines are currently capable of complying with this standard. Any minor exceptions due to the limitations of a particular system would not be expected to prejudice the understanding of a diagram otherwise claimed to comply with this standard.

It is recognized that though this standard is published in a number of parts, there may be instances when certain recommendations and descriptions are repeated. This has been kept to a minimum and it is hoped that all the needs of any specialized engineering discipline are contained in the part of this standard that deals with those specific needs.

This part of this standard deals with a variety of non-electrical diagrams including control and flow; transfer of materials (both fluids, i.e. liquids, vapours and gases, and solids); and energy transfer (hydraulic, pneumatic and mechanical).

Part 1 of this standard deals with general principles of diagram drawing and is the base document. Part 2 of this standard deals with all forms of diagrams in electrical, electronics and telecommunications engineering. Part 4 of this standard deals with logic diagrams.

Engineering diagrams are a major factor in the development of a project. They are used either to build complex engineering plants or the smallest item of equipment.

It is important that the information contained should be complete, easily understood and maintained in an up-to-date condition. In the case of certified “as-built” diagrams a design change procedure is recommended for record and historic purposes. Such a procedure is the key to ensuring control of cost, time and technical accuracy for the project.

Sequencing or progression of diagrams can be variable. It is, however, recommended that guide lines be introduced at the commencement of a project to present the assembly of information, proceeding from one diagram to the other.

Compliance with a British Standard does not of itself confer immunity from legal obligations.

Notes on the presentation of this standard

NOTE 1 The figures illustrating the text in this standard are independent and each is selected solely for its simplicity and clarity to illustrate only the text to which it relates. They are not the only possible examples and they are not intended as design examples or to be fully working diagrams, but otherwise are drawn according to the basic recommendations of this standard.

NOTE 2 Numerical values of components given in the figures throughout are arbitrarily chosen to assist in illustrating the point under consideration; they are typical and are not given as recommendations.

NOTE 3 In the figures in this standard, a convention is adopted of using capital letters for notes that would appear as part of the drawing and lower case letters are used for notes explaining the point under consideration in relation to the text. An exception to this may be found in some diagrams where unit symbols are customarily written in lower case.

Summary of Pages

This document comprises a front cover, inside front cover, pages i to iv, pages 1 to 41 and a back cover.

The BSI copyright notice displayed in this document indicates when the document was last issued.

1 Scope

This part of BS 5070 gives recommendations for the practice to be followed in preparing mechanical, process and fluid flow diagrams. It covers all aspects of diagram representation except the choice of symbols for particular components; this is the subject of BS 1553 and other relevant standards giving symbols for specific industrial use.

This part of this standard should always be used in conjunction with BS 5070‑1 and the relevant symbol standards when preparing mechanical, process and fluid flow diagrams.

NOTE 1 The relevant part of BS 5775 should be complied with for the correct application of units and symbols for quantities.

NOTE 2 British Standards detailing graphic symbols for use in engineering diagrams are listed in Appendix B.

NOTE 3 The titles of the publications referred to in this standard are listed on the inside back cover.

2 Principal types of diagrams

3 Principles of presentation

3.1 General

3.2 Cross-overs and junction of lines

3.3 Omission of lines

3.4 Arrows

4 Block diagram

4.1 General

4.2 Presentation

5 Flow diagram

5.1 General

5.2 Presentation

6 Circuit diagram (fluid)

6.1 General

6.2 Presentation

7 System and piping diagrams

7.1 General

7.2 Presentation

8 Piping and instrumentation diagrams (P and ID’s)

8.1 General

8.2 Presentation

9 Supplementary diagrams

9.1 General

9.2 Typical supplementary diagrams (Figure 17, Figure 18 and Figure 19)

BS 5070-3:1988

Engineering diagram drawing practice - Recommendations for mechanical/fluid flow diagrams

Current

Published:

29 Apr 1988