| 1 | Scheele Engineering Corp. – SECOR | | USA |
| 2 | Everett J. Prescott Inc. | | USA |
| 3 | Commercial Resins | | USA |
| 4 | United Pipe Nipple Company | | USA |
| 5 | MRC Global | | USA |
| 6 | ABT Inc. | | USA |
| 7 | Pipeline Plastics | | USA |
| 8 | Town & Country Plastics Inc. | | USA |
| 9 | Appalachian Piping Products Inc. | | USA |
| 10 | American Spiralweld Pipe Co. LLC | | USA |
| 11 | ICSE | | USA |
| 12 | EGW Utilities Inc. | | USA |
| 13 | Rovanco Piping Systems Inc | | USA |
| 14 | Oregon Steel Mills Inc | | USA |
| 15 | Berg Steel Pipe Corp. | | USA |
| 16 | Stupp Corp. | | USA |
| 17 | Charter Plastics | | USA |
| 18 | Paragon Industries Inc. | | USA |
| 19 | American Steel Pipe Div. American Cast Iron Pipe Co. | | USA |
| 20 | P.A. Inc. | | USA |
| 21 | WL Plastics Corp. | | USA |
| 22 | Woolf Aircraft Products Inc. | | USA |
| 23 | Asahi/America Inc. | | USA |
| 24 | Naylor Pipe Co. | | USA |
| 25 | Precision Welding & Fabrication | | USA |
| 26 | WS Hampshire Inc. | | USA |
| 27 | IPEX | | USA |
| 28 | Omni Steel Supply | | USA |
| 29 | Victrex USA Inc. | | USA |
| 30 | Future Pipe Industries | | USA |
| 31 | JM Eagle | | USA |
| 32 | Ratermann Manufacturing Inc. | | USA |
| 33 | GreenMount Corp. | | USA |
| 34 | F.W. Webb Company Thermoplastic Piping Div. | | USA |
| 35 | U.S. Industrial Piping Inc. | | USA |
| 36 | Georg Fischer LLC | | USA |
| 37 | AIRCOM USA Inc. | | USA |
| 38 | United Poly Systems | | USA |
| 39 | Valiant Steel | | USA |
| 40 | Federal Steel Supply Inc. | | USA |
| 41 | Piping Systems Inc. | | USA |
| 42 | Gibb Robert & Sons Inc. | | USA |
| 43 | Mammoth Carbon Products | | USA |
| 44 | FlexSteel Pipeline Technologies Inc. | | USA |
| 45 | Steel Forgings Inc. | | USA |
