Mechanical, Electrical, and Plumbing Coordination
Mechanical, Electrical, and Plumbing Coordination tests how the systems trades are installed, tested, and made to fit inside the structure. Rules come from FBC Chapters 27 through 29 (electrical, mechanical, plumbing) plus the Florida Mechanical and Plumbing Codes and NFPA 70. The exam emphasizes clash resolution, structural limits, firestopping, and testing.
Electrical
- Service, feeder, and branch capacity follow the load calculation; voltage drop is a design check, not a code minimum, but 3 percent on a branch and 5 percent total is the usual target.
- GFCI protection is required in bathrooms, kitchens, garages, outdoors, and near sinks; AFCI protection covers most dwelling branch circuits; tamper-resistant receptacles and smoke and carbon monoxide alarms are standard.
Plumbing and mechanical
- The Florida Plumbing Code governs supply sizing, drainage slope, vents, backflow prevention, and temperature-and-pressure relief discharge piping.
- HVAC work requires correct refrigerant piping, condensate drainage with a trap and an overflow path, and equipment access for service.
- Duct leakage testing and TAB verification are commissioning deliverables, not optional reports.
Coordination and firestopping
- No structural member may be cut for a pipe or duct without the engineer of record; penetrations are limited by zone and size.
- Every penetration of a fire-rated assembly needs a listed firestop system installed exactly as tested.
- Coordinate sleeve locations, hanger spacing, access panels, and valve clearances during modeling or in pre-installation meetings - not in the field.
Worked example
A 120-volt, 12-ampere load is 100 feet from the panel on No. 12 copper (about 1.93 ohms per 1,000 feet). Voltage drop = 2 x length x current x resistance = 2 x 0.1 x 12 x 1.93 = 4.63 volts, or 3.9 percent. That exceeds the 3 percent branch target, so upsize to No. 10 copper (about 1.21 ohms per 1,000 feet): drop becomes 2.9 volts, or 2.4 percent. Reasoning: the factor of two accounts for the round trip.
Traps that cost marks
- Notching a beam or wall for plumbing without engineering approval.
- Substituting generic sealant for a listed firestop system.
- Installing equipment with no service access or clearance.
- Draining condensate without a trap or an overflow protection path.
- Assuming voltage drop is a code violation rather than a performance limit.