To ensure the accuracy and consistency of glass thermometer calibration, many countries and international organizations have established relevant standards and certification procedures. For example:

1. International Organization for Standardization (ISO)
   ISO has published several standards related to thermometer calibration, such as ISO 17025, which specifies the technical requirements for calibration laboratories.

2. National Standards
   Countries have also established corresponding national standards. For example, China's JJG 130 "Verification Regulation for Glass Liquid Thermometers" details the calibration methods and requirements for glass thermometers.

3. Certification Bodies
   By obtaining certification from authoritative bodies (such as the China National Accreditation Service for Conformity Assessment, CNAS), calibration laboratories can demonstrate that their calibration capabilities meet international standards.