/ Field knowledge · Loads · Envelope
HVAC design should change with how the building is constructed.
A load file copied from the last glass office onto a CBS warehouse, or from a new shell onto a 1970s TI, is how Miami jobs get oversize equipment, short latent capacity, and comments that look like “provide calculations.”
Osmany Portal, PE writes about this in public because it shows up on real sets: the mechanical design has to follow how the building is actually constructed — mass, envelope, existing vs new, conditioned vs warehouse, not a typical that assumes yesterday’s occupancy.
What actually changes the HVAC path
- New vs existing. IMC 102 / existing-building rules, leftover duct, leftover outdoor-air, leftover combustion closets. A TI is not a clean-sheet load.
- Envelope. CBS, tilt-up, curtain wall, and a glass storefront on a CBS box are different solar and latent problems. Florida energy forms follow the envelope you drew, not the last job.
- How the rooms are used. Table 403 occupancy, kitchen exhaust, garage 404, and healthcare 170 are different methods. Mixing them on one typical is a comment.
- How the building is built around shafts. If the architecture cannot give you a grease duct, an OA intake, or a combustion-air opening, the load file will not save the permit.
Copying tons-per-square-foot
Rules of thumb skip latent load, exhaust makeup, and the actual envelope. Reviewers in Miami-Dade will ask for the method. Send architecture and the existing HVAC, not a tonnage guess.
Run first: outdoor-air estimator · 401 vs 403 · load-calc hub · existing buildings.
What to send
Architectural plans and elevations, existing HVAC if any, occupancy list, and whether this is new, TI, or a change of use. A share link is enough.
If the last job’s load file is about to get reused
Send the architecture and the existing systems. Masterbuild will say whether the method even applies before anyone prices equipment.
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.