Accreditation and Standards Compliance: Ensure the lab is accredited to ISO 17025 by an International Laboratory Accreditation Corporation (ILAC) body such as NIST’s National Voluntary Laboratory Accreditation Program (NVLAP). ISO 17025 is the international standard for quality management of a laboratory system. The laboratory shall also comply fully with all requirements of the ASTM test procedure, laboratory qualification testing, and all referenced standards. This guarantees the testing procedures and results meet industry-recognized benchmarks.

Experience and Expertise: Look for a lab with extensive experience in acoustics testing, particularly STC testing. Experienced labs are more likely to provide precise measurements and understand the nuances of different materials, construction methods, mounting types, and their implications for field performance.

Facilities and Equipment: The lab should have state-of-the-art testing facilities and equipment that are regularly calibrated and maintained. This ensures that the test conditions accurately simulate real-world scenarios.

Reporting and Analysis: A good lab will provide detailed reports that not only give you the STC rating but also explain the results in the context of your specific project. Modern test reports include photos of sample details and the installation conditions.

Customer Support: Consider the level of customer support provided by the lab. Open communication, timely responses, and the ability to discuss results and potential implications are all indicators of a lab that values its clients.

Understanding STC ratings and testing can significantly impact the success of your building projects, especially when sound control is a priority.