Mechanical Technology July 2016

Mechanical Technology — July 2016

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Structural engineering materials, metals and non-metals

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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

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.

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.