Metrication in Ireland

Information sign about the speed limit units used in Ireland

Ireland gradually adopted the British imperial measurement system, fully replacing traditional Irish measure during the 19th century, and these units continued to be used after Irish independence. In 1980 the European Union asked all of its member states to convert to the metric system, and in Ireland and the UK this process was originally to have been completed by 2009 with the UK still using imperial measurements. Metrication succeeded in Ireland with the changeover fully completed in 2005 (with few exemptions such as the ongoing use of pints and acres).

Metrication

During the First World War and after the Easter Rising, Charles A Stanuell, former President of the Statistical and Social Inquiry Society of Ireland published a paper advocating the use of the metric system and a decimal currency in the UK, of which Ireland was then a part.

Metrication in Ireland began in the 1970s and by 2005 was almost completed; the only exception being that the imperial pint (568 ml) is still used in bars for reasons of tradition. The phrase a "glass of beer" is a colloquial expression for a half-pint (284 ml). All other places must sell liquids measured in millilitres and litres.

Distance signs had displayed kilometres since the 1970s but road speed limits were in miles per hour until January 2005, when they were finally changed to kilometres per hour. Since 2005 all new cars sold in Ireland have speedometers that display only kilometres per hour; odometers generally became metric as well.

The metric system is the only system taught in schools. Beginning in 1970, textbooks were changed to metric. Goods in shops are labelled in metric units.

Continuation of supplementary Imperial units

See also: European units of measurement directives

In 2006 it became apparent that the 2009 cut-off for the use of Imperial supplementary units could cause problems in US-EU trade. After consultation, EU Directive 2009/3/EC of 11 March 2009, among other measures, permitted:

• the indefinite use of Imperial supplementary indications.
• the United Kingdom and Ireland to continue the limited exemptions concerning specified uses of the pint, mile and the troy ounce, considering the absence of any impact of these exemptions on cross border trade and the principle of subsidiarity; whilst repealing the exemption for the use of acre for land registration which is no longer applied.

These amendments were published on 7 May 2009 and became effective on 1 January 2010.

Horse racing

Horse racing in Ireland continues to use stones, pounds, miles and furlongs as measurements.

Plumbing

Ireland continued to use imperial pipe diameters for domestic copper plumbing into the 1980s, although the pipes themselves were supplied in metric lengths - the most common diameters are half-inch and three-quarter-inch. This is in contrast to the United Kingdom where copper plumbing pipes size had been standardized to Metric units since the early 1970s, although they were, and are still, referred to by their old approximate Imperial sizes of "half-inch" (15mm outer diameter) and "three-quarter-inch" (22mm outer diameter). However, by 2020, the Irish plumbing industry has almost completely migrated to the same Metric pipework standards (EN 1057) as used in the UK and across the European Union.

The above applies only to copper pipework; plastic plumbing parts moved to Metric units at the same time as the UK.

References in Oireachtas debates

• That the Government be asked to appoint a Commission, with power to examine voluntary witnesses, to inquire into and report on the desirability or otherwise of adopting the Metric System in Saorstát Eireann, Senator de Loughry (April 1923). "Notice of motion". Archived from the original on 11 June 2011.
• "Question to the Minister for Education to request support for the teachers association vote in favour of metrication". 1951. Archived from the original on 25 September 2012.
• "Question to the Minister for Finance on plans to introduce decimal coinage and the metric system". May 1964. Archived from the original on 1 September 2012.
• "Question to the Minister for Industry and Commerce to request for a decision to be made in favour of metrication". June 1967. Archived from the original on 25 September 2012.
• "Question to the Minister for Industry and Commerce". October 1967. Archived from the original on 1 September 2012.
• In the area of prepackaged goods the changeover is virtually complete, "Question to the Minister for Industry and Commerce on enforcement of the regulations on food pricing (in metric)". November 1987. Archived from the original on 1 September 2012.
• "Question to the Minister for Industry and Commerce". December 1989. Archived from the original on 1 September 2012.
• "Question to the Minister for Transport on the timetable for metric speed limits". June 2003. Archived from the original on 1 September 2012.
• "Question to the Minister for Transport on the timetable for metric speed limits". October 2003. Archived from the original on 1 September 2012.

See also

• Old Irish units of measurement
• Irish measure