International manufacturer and services provider for hot tap and hot tapping equipment and services and other pipeline maintenance equipment.T. D. Williamson, Inc - manufacturer of pipeline maintenance equipment and pipeline integrity Search TDW is the Choice for All Your Pipeline Integrity Needs. TDW's in-house, comprehensive approach to your specific project needs means we will assist from beginning to end. Experienced, dedicated engineers, project managers, technicians and support personnel are available 24 hours a day, seven days a week to design and develop solutions specific to your requ