operation of a business dealing in multi-discipline consulting and professional engineering services; namely, mechanical and structural engineering in the area of metallurgical and welding engineering, inspection, repairs and where necessary reinspection for others and the issuing of a certificate of inspection to customer specifications; namely, services in connection with inspecting overhead and mobile lifting equipment, and equipment of a similar nature, and certifying the safety and efficacy of such equipment and its compliance with specifications and regulatory requirements to customer specifications