/ Hub · IMC 407 · ASHRAE 170
A clinic is not an office with more outdoor air.
IMC 407 sends ambulatory care and Group I-2 mechanical ventilation to ASHRAE 170. Pressure relationships, filtration, air-change rates, and outdoor air are a system — not a Table 403 occupancy with a nicer diffuser.
What has to be true on the set
- Occupancy and procedure list that actually trigger 170 versus a medical office in Group B
- Room pressure relationships shown, not implied (airborne, protective, soiled, sterile)
- Filtration stages and where they sit in the air path
- Outdoor air and total air-change rates as 170 tables, not IMC 403
- Coordination with NFPA 99, infection-control, and the architect’s program
- Existing-building conversions: what lawfully remains versus what the new use demands
- M-601 columns: 170 room type, total ACH, OA, pressure sign, filtration, temp/RH, exhaust — not OA cfm/person from Table 403
- AIIR negative vs PE positive; do not mix them. See 407 room path
Masterbuild supports healthcare MEP where the program is defined. This page is not a claim of hospital-only specialization, a 170 certification, or a substitute for the facility’s infection-control authority.
Related: IMC 407 Daily Code Talk · Ventilation hub · Existing-building conversions
Send the program and the occupancy
Room list, procedures, and whether this is a clinic TI, ambulatory surgery, or an I-2 conversion. Masterbuild will say which standard actually applies before anyone sizes air changes.
Send Project Background+1 (786) 398-6940 · osmany.portal@masterbuildconsulting.com
Masterbuild provides engineering services under a written scope. Nothing on this page is project-specific engineering advice, a code interpretation for your project, or a representation about permit approval.