STL as a collaboration does not itself issue Certificates. Each STL Member testing organisation or laboratory issuing a Test Certificate is responsible for the validity and contents of that Certificate.
STL Members pledge that when testing for certification to a Standard in respect of which an STL Guide has been issued they will test only in accordance with the agreed interpretation of the Standard as given in the STL Guide.
In addition, STL Members have agreed to present Certificates in the form given in the STL General Guide.