CONSTRUCTION / HVAC

Rooftop plant and HVAC access platforms

A roof access platform does one plain thing. It gives a technician a flat, guarded surface to stand on where the roof itself will not.

Rooftop plant is awkward for the same handful of reasons every time.

• The roof has a fall in itSo nothing sits level.
• Services run at shin heightCondensate lines, chilled water pipe and cable tray run between the units.
• Nobody drew an access routeThe plant went in over 20 years in three stages, each mechanical contractor working around whatever was already up there, and nobody drew an access route for the finished result.

So the filter bank on the back of an air handling unit ends up behind a pipe run, on a slope, with a plinth to climb to reach it.

We build the platform to suit what is actually on the roof.

• A level walking surfaceOver a sloped or cluttered deck.
• Working room on the service sideNot just a path to the front of the unit.
• Landings at the panels people openSo a filter change or a belt swap happens off a proper platform instead of a ladder leaned against a condenser.

Typical work is:

• Access decks around chillers and cooling towers
• Platforms over condenser banks
• Stepped platforms across changes in roof level
• Guarded working areas at rooftop air handling units

Where plant sits near a roof edge, the platform and the edge protection are designed together instead of one being bolted on after the other. Fixed platforms, walkways, stairways and ladders are designed to AS 1657:2018.

Now and then there is genuinely nowhere to land a platform, usually plant hung off a facade or a structure with no deck under it. That work gets done off ropes by our rope access technicians instead. On a new build, the cheapest time to sort any of this out is during mechanical services coordination, before the plant is set out. Moving a condenser 400 mm on a drawing costs nothing. Moving it on a roof costs a crane.

Acoustic screens and plant enclosures

Rooftop plant makes noise, and the neighbours notice. Most Sydney councils attach noise conditions to a development approval, and plenty attach sightline conditions with them, so the plant is not to be seen from the street or from the apartments next door. That is what screening is for, built around the units:

• Acoustic slat screens
• Solid panel enclosures
• Framed louvre systems

A screen is not cladding on a frame. It is a sail. Anything you stand up on a roof catches wind, and the frame, the fixings and the structure underneath all have to take that load. Screens are engineered for the exposure at your site, and the height, the slat spacing and the panel type are made to suit the plant and the approval conditions rather than pulled off a shelf.

The part people forget is access behind the screen. Box in a row of condensers and the technician still has to get in there to service them. If the screen was drawn by someone who never pictured a filter change, there is no gate, no landing and no room to swing a panel open, and within a year somebody has cut a hole in it. We draw the screen and the access together: hinged or removable panels at the service points, and platform inside the enclosure where the plant needs it.

Engineered for your site

Everything we install is drawn before it is cut. Site measure first, then engineering drawings, then fabrication, then install.

• Site measureOn a plant deck carrying 20 years of unrecorded modifications, the site measure is the step that saves you, because what is on the drawings and what is on the roof are rarely the same thing.
• Engineering drawingsIn-house engineering means the person drawing the platform can talk to the person installing it, and the design gets checked against what the crew can physically get up there.
• FabricationSteel is fabricated to the measured dimensions, galvanised, and delivered in pieces that fit through the roof hatch or into the goods lift, because on an occupied building there is often no crane and no street closure.
• InstallStaged unit by unit, with isolations agreed in advance, hot work managed around the occupants, and the deck handed back in usable sections instead of all at the end.

Working around live plant is its own problem. You cannot switch a data hall's cooling off to put a walkway in, and a hospital will not give you its air handling for a fortnight. Most of this work happens on operating buildings. We have run that on live sites including John Hunter Hospital and Western Sydney Airport.

At handover you get the drawings and the documentation for the system, and our certification and audit team can bring it into your register and inspection program with the rest of the building's height safety. If you have a plant deck you want looked at before it goes to drawing, talk to our Sydney team, or meet the engineers and installers who run these jobs.