Dr. Charun Yafa, Assistant Director of NIMT, was invited to conduct the expert consultancy in the context of collaboration between the National Institute of Metrology (Thailand) and the Physikalisch Technische Bundesanstalt (PTB), Germany, for the PTB Cooperation Project “Strengthening Quality Infrastructure Services for Environmental and Climate Monitoring, Indonesia.” There were two missions to complete this consultancy. The first mission was to make the site visits to PT providers: PSIKHL in Serpong and ITB Lab in Bogor, on 6-7 February 2024. The second one was to visit SNSU-BSN in Serpong (the National Measurement Standard – National Standardization Agency of Indonesia) on 19-20 February 2024.