| # | Company name | Role | # of projects |
|---|---|---|---|
| 1 | T B Fire Protection | Fire protection engineering | 0 |
| 2 | T.A. Fire Control, Inc. | Fire protection engineering | 1 |
| 3 | TCAPA Engineering Consultants | Fire protection engineering | 2 |
| 4 | Techno - Advanced Inc | Fire protection engineering | 0 |
| 5 | Tecno | Fire protection engineering | 2 |
| 6 | Teepe River City Mechanical | Fire protection engineering | 2 |
| 7 | Tefire Group UAB | Fire protection engineering | 9 |
| 8 | Tennessee Auto Sprinkler Company | Fire protection engineering | 0 |
| 9 | Texas Sprinkler Inc | Fire protection engineering | 3 |
| 10 | The Baker Co | Fire protection engineering | 0 |
| 11 | The Fire Safety Division of Siemens Building Technologies | Fire protection engineering | 0 |
| 12 | The Hitchcock Co | Fire protection engineering | 1 |
| 13 | The MountainStar Group, Inc. | Fire protection engineering | 3 |
| 14 | The National Fireproofing Company | Fire protection engineering | 1 |
| 15 | The Pipco Cos Ltd | Fire protection engineering | 5 |
| 16 | The Plumbery | Fire protection engineering | 1 |
| 17 | The Scholl-choffin Company | Fire protection engineering | 0 |
| 18 | Theo Schröders Entwicklung und Beratung GmbH | Fire protection engineering | 1 |
| 19 | Thermax AS | Fire protection engineering | 17 |
| 20 | Tianjin Fire Research Institute | Fire protection engineering | 2 |