| # | Company name | Role | # of projects |
|---|---|---|---|
| 21 | Plumb Engineering, P. C. | MEP engineering | 1 |
| 22 | Plummer Associates | MEP engineering | 1 |
| 23 | PLUS GROUP Consulting Engineering, PLLC | MEP engineering | 1 |
| 24 | PMH Associates, Inc. | MEP engineering | 1 |
| 25 | Pol-Con Consulting Sp. z o.o. | MEP engineering | 1 |
| 26 | Polytech, Inc. | MEP engineering | 1 |
| 27 | PositivEnergy Practice, LLC | MEP engineering | 5 |
| 28 | Pouget Consultants | MEP engineering | 1 |
| 29 | Prairie Engineering, PC | MEP engineering | 1 |
| 30 | Prater Engineering Associates, Inc. | MEP engineering | 7 |
| 31 | Priest Engineering Incorporated | MEP engineering | 9 |
| 32 | Prime Technologies LLC | MEP engineering | 0 |
| 33 | Prism Engineering Ltd. | MEP engineering | 4 |
| 34 | Professional Engineering Consultants, P.A. | MEP engineering | 6 |
| 35 | Progressive Services Design Ltd. | MEP engineering | 1 |
| 36 | Projekt AG Planungsgesellschaft für Gebäudetechnik | MEP engineering | 3 |
| 37 | Proleed | MEP engineering | 1 |
| 38 | Property Resources Corporation | MEP engineering | 1 |
| 39 | PT. Hantaran Prima Mandiri | MEP engineering | 1 |