Slovenian National Building and Civil Engineering Institute (ZAG) is a leading Slovenian research organization in the construction sector, with over 220 employees. Specializing in structures, transport devices, traffic infrastructure, and the built environment, ZAG conducts fundamental and applied research, develops testing methods, and provides certification services.

ZAG is recognized for issuing Slovenian Technical Approval (STS), European Technical Assessment (ETA), and Environmental Product Declaration (EPD). The institute focuses on energy-saving and carbon emission reduction, particularly in building envelopes, insulating materials, energy capture, and storage.