The goal of Metrology is to protect citizens, as consumers and traders, by safeguarding their rights when commercial transactions are carried out. The need for accurate measurements was already felt by the first civilisations, which engaged in commercial exchanges, and has become even more important with increasing demands in global trade. New needs and challenges brought advances to this area, effected through new technologies, such as to meet the current demands of society.

At the Service of the Lisbon City Council since 1935

In 1812, the first steps were taken in Portugal to adopt the Metric System, a decimal system of weight and measurement units based on the length of the Earth’s meridian. The system came into effect in July 1861, after the respective Decree was published in December 1852. The Calibration Service, set to operate in the country’s councils, was decreed on 29 December 1860. Each Municipal Council was responsible for training and supervising Calibration Technicians, who were granted a professional licence for this purpose.

Created in 1935, the Lisbon City Council (CML) Calibration System, with head office at Avenida 24 de Julho, was a section of the department responsible for managing the city’s public lighting. This service remained at this address until the early 1990s. In the sequence of several restructuring processes underwent by the CML, the Calibration Service, currently known as Metrology Service, is now a section of CML’s environmental services, headquartered at the Olivais municipal premises, at Avenida Infante Dom Henrique, Lote 1.

The Metrology Service (MS) is a qualified service ensured by the Portuguese Institute of Quality (IPQ), which is responsible for governing the National Metrology System and establishing metrology regulations in Portugal.

Do you know the meaning of the popular expression “double standards”?

This phrase equates to unfairness, as might occur in weighing operations in the past. Weights and measures might differ from location to location. In order to abolish this unfairness, King Manuel I ordered the publication of the Weights Regulation in 1502 (where the weight system was explained), which established a law to be enforced in councils, known as Regulation for Officials of the Cities, Towns and Villages of these Realms. 

The main goals of the Lisbon Metrology Service are to prevent the use of different weights and measurements in commercial transactions and to ensure that rigorous standards apply to buying and selling. This entity is responsible for ensuring that all measuring instruments used in commercial transactions are checked periodically, in compliance with metrological control regulations and the standards defined by the Portuguese Institute of Quality (IPQ).

The Metrology Service checks several measuring instruments on a periodical basis, namely weights, balances, taximeters, parking meters and time meters (e.g. in pool tables).

Calibration Technicians, i.e. Metrology Technicians, are responsible for ensuring measurements are conducted rigorously, such as to protect citizens, as consumers and traders, by safeguarding their rights in commercial transactions and other activities in which measuring instruments are used:

  • Health Services, within the scope of diagnostic and treatment services provided by Hospitals, Pharmacies and Health Centres;
  • Research conducted to improve quality of life, in what concerns the instruments used in Laboratories and Analysis Centres;
  • Commercial Establishments & Restaurants, focusing on the promotion of shops with history, wholesale transactions using eco-friendly packaging and investment in quality of life; 
  • Airport safety, such as to ensure the accurate weighing of transported cargo.

Calibration Technicians

The profession of Calibration Technician, currently known as Metrology Technician, is one of the oldest in the Lisbon City Council.

The Metrology Technician course enables these professionals to guarantee product quality, by ensuring that measuring systems are completely reliable. Metrology Technicians evaluate the precision of measuring instruments, based on their profound knowledge of weights, measures and unit systems.

Although their work is largely unseen and unknown, we must not forget that such efforts are key to ensuring the fairness of all commercial transactions, which, on their turn, drive economic development in the country and the world. Who, in this day and age, haggles at the supermarket, the pharmacy, the airport or even the butcher’s, or discusses prices with the trader who weighed their products?

Thanks to Calibration Technicians, customers and traders can trust transactions. That’s how we know that 100 grams are in fact 100 grams! 5 litres must actually be 5 litres! 2 kg must be 2 kg, every single time!

The CML Metrology Service carries out metrological control in the Lisbon and Oeiras councils. A seal is used to certify that a given instrument has been calibrated, i.e. verified and found to be accurate. This label is valid for a year, as indicated by its colour, after which the instrument must be calibrated again.

Calibration Technicians Museum

The collection displayed as the Calibration Technicians Museum includes several standard weights and volume measures, primarily used by calibration technicians in their profession, as well as some pieces collected over the years.

There are many curiosities to be discovered...

Visits must be booked in advance by email, at
Visits have an approximate duration of 1h30; face masks are mandatory during the COVID-19 pandemic.
Address: Avenida Infante Dom Henrique, Lote 1, 1800-220 Lisboa. Click here for more information.

At the Technicians Museum you will gain knowledge of a few classic Portuguese films where Metrology is featured...

...and also of a few popular sayings, for good measure!

“A bunch of words”

“To give 110%”

“Size doesn’t matter”

“To run a mile"

20th-century curiosities kept at the Lisbon Municipal Archives

The World Metrology Day is celebrated on 20 May

The World Metrology Day is an event where the signing of the Metre Convention on 20 May 1875 is celebrated by representatives of 17 countries, including Portugal. The Convention led to the creation of the Bureau International des Poids et Mesures (BIPM), (International Bureau of Weights and Measures) and set the framework for global cooperation in Measurement Science and its applications, forming the basis of a coherent, universal measuring system and supporting scientific innovation, industrial production and international trade, as well as quality of life and global protection of the environment.