Posted on Wednesday, August 26, 2020 by Mads Wraa Hyttel
This blog post is the first part of two blog posts regarding thermal energy meters. In this blog post, we introduce you to the European framework for legal metrology. The second blog post informs you about first time verification of every meter. We hope you will find the blog posts interesting.
Part 1: Introduction to the European framework for legal metrology of thermal energy meters
Most of us don’t think about it but measurements are often used to determine the price. For instance, we pay for gas based on the volume, i.e. the litres or gallons we buy. Also, the price of groceries is typically determined by the measured weight. In these and many other cases, there is a buyer and a seller that depends on a correct measurement and both need to be protected against fraud or wrong measurements. To provide this protection of the buyer and the seller, most countries have laws about measurements that are used for commercial transactions and in general the term ”legal metrology” is used to describe these laws.
Thermal energy meters are also used for commercial transactions between a buyer and a seller since the price for thermal energy is based on the amount of consumed energy. Therefore, a European framework for legal metrology of thermal energy meters has been implemented. In the following, I will explain the different parts of this framework with an emphasis on how each part contributes to correct measurements and thus a fair commercial transaction.
The first part of the framework is the Measuring Instruments Directive (MID) issued by the European Union. The MID states that all heat meters are only allowed to be sold in member states of the European Union if they are approved by an independent authority and according to the European standard EN1434. This required approval of a heat meter is known as MID approval. Cooling meters are not part of the MID but in several countries, including Denmark, cooling meters are only allowed to be sold, if they have a national cooling approval that states that the cooling meter comply with EN1434. All our cooling meters are therefore sold with a Danish cooling approval.
You can check our second part of the series which informs you about first time verification of every meter here.
The European standard EN1434 on thermal energy meters is today the most important standard in the world for thermal energy meters and is therefore also used outside Europe in countries like Canada and China. For a thermal energy meter to be compliant with the EN1434, it must initially pass a long range of type tests before an approval can be issued. This includes type tests that evaluate if the thermal energy meter has the specified accuracy and durability. The performance when operating in conditions with a very high level of moisture is also evaluated, which is very relevant for cooling meters. After an approval has been issued, the EN1434 standard has requirements for mandatory tests of every thermal energy meter before it can be sold. These mandatory tests are known as first-time verification of the thermal energy meter. Since both MID and Danish cooling approvals require the thermal energy meter to be compliant with EN1434, the compliance to EN1434 is in practice stated in the corresponding approval of the thermal energy meter. As a leading manufacturer within thermal energy meters, all Kamstrup’s heat and cooling meters are compliant to the 2015 version of EN1434, called EN1434:2015, which is the newest EN1434 standard.
The European framework for legal metrology of thermal energy meters also requires that the production processes are approved. This is known as MID – Module D certification and maintaining this certification requires audits by an independent authority. For instance, when a newly approved product is put into production, an audit is performed. Furthermore, many European countries have market surveillance authorities that routinely test if the thermal energy meters, that are sold in the specific country, are compliant with EN1434 and can remove any non-compliant meters from the market. Buying meters from a manufacturer controlled by a 3rd party authority ensures an accuracy and a quality which as a minimum comply to the description in the standard. In this case the standard is used to control each meter in every batch of meters, installed at European utilities. In case anyone doubts the accuracy of a thermal energy meter, the verification process equips each meter with a set of unique certificates for that exact meter, making it easy to control the verification process and recheck the meters performance.
Compliance to the EN1434 standard also has an impact in relation to installation of meters. In most cases installation of an energy meter is a significant part of the investment, which should be optimized as much as possible. Furthermore, a faulty installation will typically lead to wrong energy measurements or costly water leaking and disputes with the consumers. The EN1434 standard also addresses this aspect. Constructional requirements for thermal energy meters must be fulfilled before the thermal energy meter is compliant with EN1434.
The constructional requirements include preferred dimensions for flow meters and requirements to threads and flanges. For instance, threads shall comply with EN ISO 228-1. Installing thermal energy meters complying with EN1434 makes it easier to perform an installation of high quality with minimum usage of time. Even many years later, when it is time to replace an old meter, it is easy to find a new meter, that fits between the pipes, without any need for changes to the installation.
A sum upTo sum up, choosing among meters complying with the EN1434 standard and with an appropriate heat and cooling approval makes it easy for you to compare meter specifications and chose the meter that suits your demands. Buying meters complying with the EN1434 standard also provides you with a large range of benefits such as:
- All meters are tested before leaving our factory, ensuring your investment in high quality meters
- Aspects which affect the lifetime are described in the EN1434 standard, ensuring you about the meter's capabilities
- Accuracy defined for each meter, proven in a unique set of certificates, is your proof for valid billing data.
Besides this you will find installation and retrofitting easy and similar from case to case.
At Kamstrup, our ambitions continue beyond complying with EN1434:2015. We continuously participate in all relevant standardization work, to inspire, within thermal energy meters as well as within communication standards. So, when it comes to standards and regulations we are already in the lead and this is our foundation for delivering a thermal energy meter with high value and reliability.