Having specified the required noise emissions for a project's component, it is often necessary to ascertain that the component has achieved its required acoustic performance. This can be determined either from measurements at the suppliers facility or more commonly in service at the operational plant.  Rigorous performance testing specifications either Standard based or project specific can be determined as part of the components purchase order.  In situ testing is often a complex procedure requiring the expertise of Acoustic Professionals using standard or bespoke testing procedures.