What is metrology? The role of security seals

Metrology and seals for gas, electricity and water meters


Metrology is the science of measurement and guaranteeing consistency and standardization in all areas of society. In order for such measurements to be accurate, the metering equipment or systems must comply with a State Metrological Control to guarantee their reliable operation.

Even though it is a discipline which often goes unnoticed by the general public, it is present in the daily life of people in all kinds of activities. For example, to cite some of its most common practical applications: traffic control speed radars, weighing packages for sending, measuring car tyre pressure, X-ray treatment in hospital, domestic supplies such as electricity, gas and water, etc. In all these cases, accurate measurement is essential for the progress of international industry and trade.


In Spain, the correct application of metrology is the responsibility of the Centro Español de Metrología (Spanish Metrology Centre). As a dependent body of the Ministry of Development, it has the following goals:

  • Determining the legal units of measurement and carrying out official calibrations in order to unify all measurement standards in Spain.
  • Checking the exact operation of metering systems to prevent fraud.

Industrial quality control is based on metrology, which represents one of the fundamental pillars together with the accreditation and standardization or certification of companies.

The Centro Español de Metrología is maximum authority within the Spanish metrological infrastructure. The following diagram, taken from an article by experts María Peñahora and José Ángel Robles, gives an impression of the complexity of the system:

Metrological infrastructure in Spain

The State Metrological Control

The State exercises legal metrological control over metering instruments having an impact on commercial transactions. It is responsible for:

  • Evaluation prior to the commercialization of the equipment: the manufacturer usually entrusts it to a Notified Body or a Metrological Control Agency. These must prove that the measuring instrument complies with the applicable technical requirements. It is at this point of the inspection that the security seals are applied, to prevent the manipulation of the device’s measuring mechanisms.
  • Periodic inspection and monitoring of equipment and following repair or modification: a control formula to verify that the instruments continue to record measurements in compliance with the permissible margin of error. If the equipment does not pass this inspection, a red tag will be placed on it to disable its use.
  • Establishing the useful life of the measuring instrument.

According to the Spanish National Accreditation Entity (ENAC), the main types of equipment subject to this control are: taximeters, acoustic instruments, electricity meters, dispensers, weighing instruments, pressure gauges, opacimeters, exhaust gas analyzers, fuel dispensers, water meters, gas meters, breathalysers and speed control radars.

The role of security seals in metrology

Security seals play an essential role in the field of legal metrology. There are the key instrument to protects and guarantee the correct and accurate operation of metering systems for our domestic utility supplies. Its manipulation is a direct sign of infringement and can result in significant fines and penalties for both parties.

1. Button-type security seal for electricity, gas and water meters and taximeters

Button Seal security seal for gas, electricity and water metersThe Precintia Button Seal model is suitable for use in electricity, gas and water meters, and can also be applied to taximeters and weighing scales. Manufacturers of metering instruments used by experts in metrology also use this type of seal.

The Button Seal security seal is made of polystyrene and is a replacement for classic lead seals (for shipping containers and weighing scales). This security seal is applied using specially designed pliers capable of handling the corrugated wire that must accompany it. The default colour is green, but this may be customised.


2. Security seal with rotary lock for electricity, gas and water meters and taximeters

In the case of seals for electricity, gas, water or taxi meters we find another type of device with a rotary lock. It is ideal for sealing small holes. It follows a somewhat more sophisticated system than the previous one: it has two pieces of plastic through which a corrugated, braided or non-conductive steel cable is threaded.

  • Roto Seal security seal: The Roto Seal model can be sealed automatically using the patented Roto Press machine. It winds the wire inside the seal and places a mark on it. The flag is marked using laser printing.
  • The Euro Tool Less and Toolless Double Flag Security seals: The Euro Tool Less is installed manually. The difference between the two models in that the latter has a second flag for an additional mark if necessary. In addition, Precintia has a new version made of resin that ensures greater strength for cases where it is necessary to seal dispensers or meters of petrol or other liquid solvents.

Roto Seal security seal Euro Tool Less security seal

3. Strap type security seal for electricity and water meters

Bi-Lok indicating strap seals are used with electricity, water and gas meters, and also have many applications in the automotive, transport and logistics sectors. Marking is by laser printing, which is exceptionally robust and ensures that the information is not erased. It is made of nylon and is available in yellow, black and blue.

Precintia Bi Lok security seal for meters

Only after answering the question “what is metrology?” can we grasp the importance of this science in our day to day lives and its close connection to security seals. So seals for electricity, gas and water meters and taximeters belong to the largest set of metrology seals. Do not hesitate to contact us if you need the assistance of a trusted security seals provider.

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