Commercial Systems
A commercial system is bigger, serves people who did not choose to be there, and comes with documentation requirements a house does not have.
Short answer
The system is larger, the air handling units are the main work, and the reasons for doing it are tenant complaints, a building standard, an insurer or a regulator rather than a homeowner preference. The deliverable is frequently the report as much as the cleaning, and the scheduling around occupancy is half the project.
What is different
Air handling units rather than a furnace: large cabinets with coils, filter banks, fans, mixing boxes and dampers, and that is where most of the work is.
Return air plenums above suspended ceilings, which are continuous and are effectively a dusty room acting as a duct.
Outside air intakes and mixing boxes, which bring in whatever is near them.
Variable air volume boxes and reheat coils, which are individual units throughout the building.
Kitchen and process exhaust, which is a separate specialized scope.
And documentation, because the reason for the work is frequently a tenant complaint, a lease obligation, an insurer or a regulator.
The ceiling plenum
In most Toronto commercial buildings the space above the suspended ceiling is the return air path. It is continuous across tenant lines, it contains everything that has ever been installed up there, and it is the route by which one tenant odour reaches another. Cleaning the duct and ignoring the plenum misses the actual return air path.
A proper scope
Air handling units: coils, drain pans, fan wheels, cabinet interiors, filter banks and dampers.
Supply and return ductwork, with access openings cut and properly sealed.
Diffusers, grilles and registers throughout.
VAV boxes and reheat coils where present.
The ceiling plenum where it is the return path.
And a written report with photographs before and after, by area, which is frequently the actual deliverable.
Scheduling and access
Out of hours or in phases, because the system has to be off and the spaces have to be accessible.
Tenant notice, which is a lease obligation in most cases and a courtesy in all of them.
Protection of tenant space, equipment and finishes.
Coordination with the building mechanical contractor, because shutting down and restarting the system properly matters.
A plan for what happens if something is found — a failed coil, a damaged damper, a wet plenum — because something will be.
And a maintenance interval set from what the first clean reveals rather than from a generic schedule.
Common questions
What is the main work on a commercial system?
The air handling units — coils, drain pans, fan wheels and filter banks.
Does the ceiling plenum need doing?
Where it is the return air path, yes. Otherwise the actual return is being ignored.
What should the deliverable include?
A written report with before and after photographs by area.