How to Plan an HVAC Upgrade Without Shutting the Building

 Replacing plant in an occupied building is a scheduling problem more than a technical one. The equipment is straightforward. Doing it while tenants trade, staff work and nobody loses cooling for a week is where projects succeed or go badly.

Most of the difficulty is decided before anyone turns up with a crane.

Establish what the building does before you touch anything

Measure how the building currently performs and record it, because you'll want to prove the upgrade worked.

NABERS rates buildings on a six star scale using independent assessors, with ratings audited by government and valid for 12 months, and represents the current operational performance of your building rather than how it was intended to perform.

Whether you pursue a formal rating or just keep your own consumption and complaint data, the principle holds. A before figure is what makes the after figure meaningful, and it's impossible to capture retrospectively.

Record the complaint volume too. On a building where comfort was the reason for the upgrade, a drop in complaints is often more persuasive to the people who approved it than a consumption figure.

Stage the work by zone, not by equipment type

The instinct is to replace all the units of one type together because it seems efficient. In an occupied building, that usually means a large part of the floor plate loses cooling at once.

Stage by area instead. One floor, one wing or one tenancy at a time, so the affected population is small and relocatable at any given point. It costs a little more in mobilisation and it's the difference between an inconvenience and an incident.

Work out what each stage actually disrupts

Before committing to a sequence, work through what each stage takes offline.

Which spaces lose cooling, for how long, and during which hours. Whether power needs isolating and what else is on that circuit. Whether ceiling access affects lighting, sprinklers or data. Whether the crane lift closes a car park or a footpath, and what permits that needs.

The second order effects cause more complaints than the HVAC outage does.

Noise and access hours are part of that. Work that's fine at ten in the morning in an industrial building is not fine above a consulting suite, and it's better to agree the hours than to discover them.

Keep temporary cooling in the plan, not in reserve

For critical areas and for stages that run longer than a day, portable or temporary cooling should be priced in rather than held as a contingency.

Work out in advance where units can discharge heat, whether there's power for them, and who has access to the spaces they need to go in. Hiring in a hurry during a heatwave is expensive and sometimes impossible.

Choose the season deliberately

Shoulder seasons are the obvious window, and they fill early with everyone else's projects.

Plan far enough ahead that you get autumn or early spring rather than taking whatever's available. Summer work in an occupied building is possible and it costs more in temporary cooling, complaints and risk.

Tell tenants early and specifically

Vague notices produce more complaints than the work does.

Tenants want to know which dates affect them, which hours, what conditions to expect, who to contact and what's being done about it. Giving them that a few weeks ahead lets them plan around it. Finding out on the morning does not.

Follow up when a stage completes too. People assume nothing happened unless someone tells them.

Protect the critical spaces first

Server rooms, cool rooms, medical areas and any tenancy with contractual obligations should be identified before the sequence is set.

Either they're served by plant that isn't in scope, or they get temporary cooling for the duration, or their stage is scheduled when the consequences are lowest.

Confirm which plant actually serves them rather than relying on the drawings. Service to those rooms is frequently not what the as built documentation says it is. What shouldn't happen is discovering mid project that a comms room was on the unit that came out this morning.

Commission each stage before moving on

The temptation at stage three is to keep installing and commission everything at the end.

Commission as you go, with measured results for each stage, so problems surface while the contractor is still on that part of the building. It also means each completed area is genuinely finished rather than nominally finished.

When you're briefing air conditioning contractors in Brisbane on a staged upgrade, ask them to propose the staging rather than specifying it yourself. A contractor who has done this before will see sequencing constraints that aren't obvious from a floor plan.

 

Frequently asked questions

Can plant be replaced without shutting the building? 

Usually yes, by staging the work area by area and providing temporary cooling for critical spaces during their stage.

How should the staging be decided?

By zone rather than by equipment type, so only a small part of the building is affected at any time and occupants can be relocated if needed.

When is the best time to do an upgrade?

Shoulder seasons, booked well ahead. Summer work in an occupied building is possible but costs more in temporary cooling and disruption.

How much notice should tenants get?

Several weeks, with specific dates, hours and expected conditions rather than a general notice. Follow up when each stage finishes.

Should each stage be commissioned separately?

Yes. Measured results per stage mean problems surface while the contractor is still working in that area.