Imaging modalities are among the most demanding tenants in a hospital: a single MRI, CT, angiography, or PET/CT unit concentrates extreme dead loads on a small footprint, rejects continuous heat that must be removed without interruption, and draws electrical service whose quality and continuity directly affect image integrity and patient safety. The mechanical, electrical, plumbing, and structural (MEPS) design for these rooms is set by vendor pre-installation requirements layered on top of code, and getting the building-systems envelope wrong is one of the most expensive and schedule-destructive mistakes in healthcare construction. This article covers the structural, HVAC, chilled-water, and power infrastructure that heavy modalities require — the radiation-shielding design, the medical physicist's role, and the MRI's magnetic shielding, quench vent, and RF cage are covered in adjacent Articles.

The vendor pre-installation manual governs — and arrives late

Before any of the building-systems numbers below can be fixed, the project needs the OEM site-planning / pre-installation manual for the specific make and model selected. Every major manufacturer — GE HealthCare, Siemens Healthineers, Philips, Canon Medical, Hologic, and others — publishes a detailed site-planning document that specifies exact equipment weights and point loads, minimum room perspectives and door/corridor clearances, heat-rejection (BTU/hr) loads by component, chilled-water flow and temperature requirements, electrical service size and power-quality limits, magnetic and RF requirements (MRI), and environmental tolerances (temperature, humidity, vibration, magnetic-field interference).

Two realities shape the schedule:

• The manual is model-specific and is not final until the equipment is selected and the vendor configuration is locked. Designing a generic "MRI room" or "cath lab" to placeholder loads invites costly redesign when the actual unit lands. The MEPS and structural design should be treated as delegated/deferred design that converges once the OEM document is in hand.
• Equipment selection frequently lags architectural and structural decisions. Owners and PMOs should force the modality and vendor decision early, obtain the site-planning manual as a contract deliverable, and treat its issue date as a critical-path milestone. A common mitigation is to design the shell and structure to a conservative envelope that bounds the likely vendors, then confirm against the chosen unit.

When the vendor and design teams disagree, the vendor manual governs the equipment interface; code (IBC, NEC, ASHRAE 170, NFPA, FGI) governs life safety, occupancy, and the broader building. Both must be satisfied — they are not substitutes for one another.

Structural loads and point loads

Heavy modalities drive structural design in three ways: total weight, concentrated point loads, and vibration/deflection sensitivity.

Equipment weight (typical orders of magnitude — confirm against the OEM manual):

Several structural design drivers recur:

• Point loads and load paths. The magnet or gantry sits on a few feet of floor; the slab, beams, and columns below must carry that concentration down to foundation without overstress. On upper floors this often requires localized slab thickening, added reinforcement, or supplemental steel. Retrofits into existing buildings frequently require structural reinforcement that can dominate cost and schedule.
• Ceiling-mounted equipment. Angiography C-arms, surgical-style imaging booms, ceiling-mounted tube supports, and overhead patient lifts hang from the structure above the room. The framing above must be designed and coordinated for these suspended loads, including dynamic motion, and the unistrut/embed layout must match the vendor's mounting template exactly.
• Floor flatness and levelness. OEMs specify tight flatness/levelness tolerances (often a fraction of an inch over the equipment footprint) for proper operation and image geometry. This becomes a slab finishing and quality-control requirement.
• Vibration and deflection. MRI and high-resolution CT are sensitive to floor vibration from nearby mechanical equipment, traffic, elevators, helipads, and adjacent construction. The vendor specifies maximum allowable vibration (velocity/acceleration limits by frequency) and floor deflection. A pre-construction vibration survey of the candidate location is standard practice; if the site exceeds limits, isolation or relocation is required. Magnetically and acoustically sensitive equipment may also be sensitive to large moving steel masses (vehicles, elevators) nearby.
• Rigging and access path. The structure and the route in must allow the equipment to be delivered. The delivery/rigging path, knockout panels, crane picks, and floor-loading along the path are coordinated early; magnet rigging and ramp-up are covered in the activation Article.

Governing references: the International Building Code (IBC) sets occupancy, structural live/dead-load, and seismic requirements; in seismically active jurisdictions, anchorage and bracing of the equipment itself (not just the building) is required, and the OEM provides seismic anchorage details that the structural engineer of record must accept. The AHJ (Authority Having Jurisdiction) — and in California the state hospital-building authority HCAI (formerly OSHPD) — reviews and approves the structural design for healthcare occupancies, with notably rigorous requirements for hospital buildings.

HVAC: ventilation, temperature, humidity, and heat rejection

Imaging rooms place two distinct demands on HVAC: the clinical-environment requirements set by code and the FGI Guidelines, and the heat-load and tolerance requirements set by the equipment.