New material option for heat meters: measuring tube made of high-performance composite instead of lead-containing brass

Under current legislation, the RoHS exemption for lead in brass is limited until 30 June 2027. Engelmann is therefore already offering an alternative today: the SensoStar UC ultrasonic heat and cooling meter features a highly resilient measuring tube made of Premium Composite.
Engelmann Sensor GmbH is expanding its portfolio with the SensoStar UC. In this ultrasonic heat and cooling meter, the measuring unit is made of a glass-fibre-reinforced composite material. This enables the company to offer an alternative to measuring tubes made of lead-containing brass.
The background to this is the requirements of the RoHS Directive: material selection is becoming increasingly important for manufacturers and users of electrical and electronic equipment. The European RoHS Directive generally limits the lead content in homogeneous materials to 0.1 percent by weight. For brass as a copper alloy, RoHS exemption 6(c) of Annex III currently applies. According to this exemption, the alloy may contain up to four percent lead by weight, although this does not mean that this applies to every type of brass. With Delegated Directive (EU) 2025/2364, the European Commission has limited this exemption until 30 June 2027. A further application for renewal of this exemption has been submitted. However, no decision has yet been made. The current development nevertheless clearly shows that manufacturers need to review the use of lead-containing materials and available alternatives over the long term. With the SensoStar UC, Engelmann is already providing a corresponding material option today. The measuring tube uses a composite material with a glass fibre content of 50 percent. The material is dimensionally stable in long-term operation and resistant to chemical deposits. One focus of the development was mechanical resilience and behaviour during installation. Engelmann has also carried out a series of in-house stress tests and documented them in videos. Among other things, the tests examined union nuts applied at an angle, offset pipe connections, and high tensile and torque loads. In the selected test setups, the thread remained undamaged even when a union nut was applied at an angle using a tool and deliberately excessive force. In another demonstration test, a recycling box weighing around 800 kilograms was lifted using a single measuring tube. Engelmann also carried out tensile and torque tests. The tests are intended to illustrate the behaviour of the material under selected high loads, some of which deliberately go beyond everyday practical conditions. They should not be understood as a general direct comparison of all technical properties of composite and brass. However, they demonstrate the practical capabilities of composite compared with lead-containing brass in everyday use. With the SensoStar UC, Engelmann is adding an additional material option to its existing brass variants. Metering service providers, specialist installers and building managers can already use a measuring unit today whose measuring tube does not rely on lead-containing brass, regardless of how the European regulation of RoHS exemption 6(c) develops in the future.

About Engelmann

Engelmann Sensor GmbH was founded in 1976 and has since developed into a technologically leading manufacturer of heat and cooling meters. During this time, well over twelve million meters have been produced, reliably recording consumption data. The meters are used worldwide. In Germany, they are used primarily in rental properties, enabling ancillary cost statements to be prepared. In addition to cooling and heat meters, Engelmann also produces and distributes heat cost allocators, water meters, smoke alarms, and suitable software for metering service providers. Engelmann currently has three locations in Germany: two in Wiesloch-Baiertal and one in Hirschhorn am Neckar. The company employs almost 190 people in Germany and has a subsidiary in Suining, China, where almost 50 people work.

[Video] Suitable video material

Manual thread destruction test: https://youtu.be/feA6uIBt5Mo
Laboratory test on fracture behaviour: https://youtu.be/2ABrMKK3k6g
Destruction test with excessive torque: https://youtu.be/GuqYYgv3OtE
Weight test with 800 kg recycling box: https://youtu.be/ajtmksg-p0U
Destruction test with offset pipe installation: https://youtu.be/uM2Ngjwy9X4

[Links] Suitable links

Delegated Directive (EU) 2025/2364: https://eur-lex.europa.eu/legal-content/DE/TXT/?uri=CELEX:32025L2364
Application for renewal of exemption 6(c) of Annex III: https://environment.ec.europa.eu/document/2e1f3934-a6e0-406a-9c7b-491f7a34fcb7_en
SensoStar UC product page: https://www.engelmann.de/product/premium-komposit-ultraschall-waermezaehler-sensostar-uc/