Refs: IMC 304.6-304.12; IMC 308; IBC; NFPA 30A.
Plain English:
304.6 Public garages: Mount appliances 8 ft or higher above floor. If vehicles pass below, meet MI clearances and set the unit 1 ft above the tallest garage door opening. Exception path: allow with impact protection and 304.3, plus NFPA 30A.
304.7 Private garages/carports: Mount 6 ft or higher above floor; or use impact protection and 304.3.
"Installed per 304.3": Treat rooms opening to a private garage as garage; put ignition sources 18 in or higher, or use an FVIR-listed appliance allowed at floor by its listing/MI; keep MI on site.
304.8 Boiler/furnace rooms: Provide IBC construction/protection.
304.9 Clearances to combustibles: Keep clearances per listing/MI; reduce only via IMC 308 (no doorstops/closers/drapery ties).
304.10 Clearances From grade: Support on a level slab 3 in above adjacent grade, or suspend 6 in above grade.
304.11 Guards (roofs/edges): If service points or roof hatches are within 10 ft of an edge with a drop over 30 in, provide guards 42 in high, blocking a 21-in sphere, extending 30 in past each end; meet IBC loads.
304.12 Area served: Permanently mark appliances that serve areas beyond the room they're in (unique ID + area served).
On Plans: Why It Matters
These are frequent inspection gates: garage heights, misused impact-protection path (without 304.3/NFPA 30A), missing IBC room protection, bad combustible clearances, pads poured too low, missing roof guards, and unlabeled "area served." Each one means holds and rework.
🧾 Where To Show It (sheet map)
M-001: Note 8-ft public / 6-ft private rules; impact-protection + 304.3 path (and NFPA 30A where public); IBC boiler/furnace protection; 3-in slab / 6-in suspend; roof guard criteria; area-served marking.
M-101+ (Plans): Dimension heights above floor; show impact protection; outline roof guard extents; annotate pad elevation; place area-served IDs.
M-501/502 (Details): Garage mounting/elevation; impact protection; roof guard (note IBC loads); IMC 308 shields; grade pad.
M-601 (Schedules): Mounting Height; Impact Protection (Y/N); Roof Guard (Y/N); Clearance to Combustibles-MI page; Pad Elevation (+in); Area Served.
Code Path: Condensate and Seismic Documentation
Show condensate drain routing from every cooling equipment unit to the drain, with required trap depth called out on the condensate detail.
For seismic design categories C-F: M-501 must show seismic bracing details for all suspended equipment and duct - reference IBC Ch. 16 and show operating weight and center of gravity.
Condensate drain pipe size, slope, and material must be shown on the detail or noted on M-001.
Check: Condensate and Isolation Verification
Confirm every cooling unit (FCUs, AHUs, DX split systems, ductless mini-splits) has a condensate drain routing shown to a drain, indirect waste receptor, or condensate pump.
For equipment in attics or above occupied ceilings, confirm a primary drain pan and an auxiliary condensate alarm or secondary drain are shown per manufacturer requirements.
Verify the seismic design category is identified on M-001 and bracing requirements are addressed consistently across equipment and suspended ductwork.
Review Risk:
Missing or incomplete condensate routing creates water-damage and startup risk; coordinate the Section 307 disposal and overflow-protection path before operation.
Missing secondary condensate drain or alarm for equipment above occupied spaces requires a field-installed solution if not shown in the permit set.
Seismic bracing for suspended mechanical equipment without referenced IBC calculations is a first-cycle structural review flag.
Field Tip:
Public garage: pick and state one path: 8-ft mount; vehicle-pass path (MI clearances and +1 ft above tallest door); or impact protection + 304.3 with NFPA 30A.
Private garage: 6-ft mount or impact protection + 304.3.
Grade/roof: show the +3-in slab (or 6-in suspension) and guard height/extent/load note.
Labeling: mark the area served on the unit and in the schedule.
Masterbuild QA Lens
Garage mounting heights (8 ft / 6 ft) and clearances to combustibles are straightforward rules, but they fail inspection at high rates because they were left to the contractor. Dimension mounting heights from finished floor on the mechanical sections. Show clearance-to-combustible notes on M-501 details. Note the area-served marking requirement for equipment that serves multiple zones.
Drawing / Submittal Check
Coordinate condensate under Section 307: show the applicable source, drain route, pipe size/material/slope, trap where required, approved disposal point, overflow protection, pump interlock, identification, and maintenance access. Where seismic forces apply, route support, anchorage, and bracing to the project structural basis.
Common Review Risk
The equipment is installed and started before the condensate disposal and overflow response are complete or inspected. Treat condensate as a water-damage control system, not an incidental field connection.
When To Escalate
Escalate when the seismic restraint design for mechanical equipment conflicts with the seismic design of the building structure - when the mechanical restraint attachment points are in locations that the structural engineer does not approve. Seismic restraint conflicts require a joint review by the mechanical and structural engineers before the restraint design is finalized.
Load Assumption Check
Installation requirements for fuel-burning equipment include combustion air volumes that add to the envelope infiltration and mechanical ventilation loads. Confirm combustion air calculation is on the drawings and accounts for the equipment's full input BTU rating.