Third-party inspection company
A third-party inspection agency (TPIA or TPI) is a business organization, complying with the ISO 17020 standards. Third-party inspection or "Category A" is the most stringent of the 3 categories of inspection organizations that the standard specifies. Such organizations are third-party inspection agencies that must not be involved in any activities other than inspection and testing. Based on this requirement, the third-party inspection agency must not be involved in design, procurement, fabrication, construction, or installation. All companies and parties such as buyers, sellers, engineering companies, plant owners must have access to these agencies and use their services. Confidentiality, independence, impartiality, and integrity are important conditions for being a third-party inspection agency.

References 

Quality control