Mechanical Technology July 2016

⎪ Structural engineering materials, metals and non-metals ⎪

Specifications, standards and codes In principle a standard is a document, prepared and published in accordance with established procedures that applies collectively to codes, specifications, recommended practices, classifications, test methods, and guides. Standardisa- tion refers to the process of establishing, by common agreement, the criteria, terms, principles, practices, materials, items, processes, equipment, parts, sub- assemblies, and assemblies appropriate to achieve the greatest practicable uni- formity of products and practices. Standards ensure a minimum feasible variety of such items and practices. Specifically: • A specification document is generally considered to be a working or busi- ness document, developed by one entity, which may use content from one or more standards and may alter the said content to meet whatever needs. They are intended to clearly and accurately describe the technical requirements of any given product or process. • A standard is a set of technical defini- tions and guidelines covering specific narrow topics that function as input for designers, manufacturers, operators, or users of equipment – an agreed way of doing something. Whilst standards rarely cover all known exceptions for all circumstances, they are typically at the heart of quality management and control systems such as ISO 9000. • Codes are a mandatory collection of standards, adopted by one or more governmental bodies, or incorporated into a business contract. Codes are enforceable by law. Standards are powerful tools that can help drive innovation and increase pro- ductivity. They can make organisations more successful and people’s everyday lives easier, safer and healthier. They represent the distilled wisdom of people with expertise in their subject matter and who know the needs of the sectors they represent. The purpose of a standard is to pro- vide a reliable basis for people to share the same expectations about a product or service. Standards help to facilitate trade; provide a framework for achieving cost effectiveness, efficiency and interoper- ability; and they enhance consumer protection and confidence. q

for resolving international disputes. The United States never became a member, but the United Nations Organisation (UN) was founded after the Second World War with similar but broader objectives. As international trade increased the need for common specifications developed. The International Standards Organisation (ISO) was founded in February 1947 to promote ‘worldwide proprietary, industrial and commercial standards’ . The USA has never been a member. The GATT agreement of 1948 dealt with regulation of trade between partici- pating countries by providing a frame- work for negotiating trade agreements and a dispute resolution. The World Trade Organisation (WTO) was formed in 1995 to take over GATT responsibilities. The European Union grew from the 1951 Coal and Steel treaty between six countries to manage heavy industries. These countries agreed on a common market in 1957. Membership was ex- panded in 1973 and the single European act of 1987 expanded common market flexibility paving the way for the com- mon EN specifications and standards we see today. Working in conjunction to simplify understanding, the ISO and EN specifica- tions have moved closer together. There is a gentleman’s agreement that attempts to make all EN standards into ISO standards and vice versa, but this does not work for all standards. Harmonised EN Standards apply only to those that are considered relevant to satisfying European Safety Requirements (ESR) in products (such as pressure vessels) in support (such as welding) and engineering material directives. Harmonised standards contain an appen- dix Z, which defines which directives and ESRs the standard meets. For example, EN ISO 15614 for the specification and qualification of welding procedures will be harmonised, but other routes for weld procedure approval may not be, such as EN ISO 15610, EN ISO 15611, EN ISO 15612, etc. From time to time, various countries’ standards clashed. Why? First, the base philosophy differs, between method- based requirements (input – what to do); and end-specifications or performance- based philosophies (output – what the project or element should do). The choice reflects local culture and the practical consequences lie in risk apportionment.

standards and systems being used by electrical engineering companies. The Engineering Standards Committee was established in London in 1901 as the world’s first national standards body. It subsequently extended its standardisation work and, in 1918, be- came the British Engineering Standards Association, adopting the name British Standards Institution (BSI) in 1931. National standards were adopted uni- versally throughout the country. These enabled markets to act more rationally and efficiently, with increased levels of cooperation. After the First World War, similar national bodies were established in other countries. The Deutsches Institut für Normung (DIN) was established in Germany in 1917, followed by its counterparts, the American National Standard Institute (ANSI) and the French Commission Permanente de Standardisation, both in 1918. Because specification authorities developed separately, the nature and phi- losophy of specifications was affected by the cultural traits of the country or coun- tries responsible. These traits include choices such as professionalism versus statutory control; uniformity versus flex- ibility; conservatism versus optimism; and secrecy versus transparency – phi- losophies that are also reflected in the education systems of different countries and in national ways of thinking. As an example, the US standards for welded fabrication tend towards method specifications. Provided the methodology is followed correctly, the risk of failure is taken by the client. Inspection is easy. On the other hand the European EN codes tend towards performance standards. Whilst more design and fabrication flex- ibility is given, the risk is carried by the designer/fabricator. Not surprisingly, the EN codes appear more lenient but require more skilled interpretation and more competent engineering. More specific information gathering and testing may be required and inspection is more complex. Initially countries were largely isolated in terms of technology development with specifications developing separately in different countries. Over time organ- isations seeking common approaches emerged. The League of Nations, first proposed by US president Woodrow Wilson as part the plan for an equitable peace in Europe, was created in 1920 to provide a forum

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