The Holiday Inn at Melbourne has been in the news recently, as the site of virus contamination suspected to be through the ventilation system. Archi-spotters will have recognized the concave shape of the hotel walls as one of several similar designs in Australia. Firstly, on the design; secondly, on the ventilation.

The floor plan, based on a triangle, was developed in the USA in the 70s by ‘Travelodge Hotels’. It’s a masterpiece of modernist minimalism: the central core is equally distant from a fire stair at the end of three double loaded corridors, minimizing non-monetised circulation space. The curved concave exterior means the that the widest part of each room is along the internal corridor, allowing for entry, storage and bathroom and the room proper narrows to the smallest amount of window required for light and view.

It was all about efficiency: a minimum circulation area servicing the maximum number of rooms; the room shape widest where needed, narrowing towards the outside – the expensive area of the façade. The Travelodge ‘Tri-Arc’ system was flexible: seven or nine rooms per side; between 5 and 15 floors. In the USA they are in Portland OR, Denver CO, Houston TX, Mt Laurel NJ, Salt Lake City UT, San Diego CA and even at Walt Disney World. You can find one in Toronto Canada and Narita Airport in Japan.In Australia, in addition to Melbourne there are Tri-Arcs in Camperdown and Albury in NSW, Geelong and Darwin. There is even one in Port Moresby.

Now to ventilation. In a sealed building, such as a hotel with no opening windows, fresh air must be provided from the outside into habitable rooms, for oxygen to replace CO₂, and to remove odours. Air is circulated from an entry point, usually on the roof or a higher facade level, away from pollution such as roads. The air is then fan pushed through ducts in the building to all habitable rooms, and then exhausted out, through more ducts to the outside.

This is ‘mechanical ventilation’ often erroneously referred to as ‘air-conditioning’ because it is now used to deliver heating and particularly cooling, but historically it predates its use for thermal comfort; it is beautifully laid out by Reyner Banham in ‘Architecture of the Well-Tempered Environment’ in 1969. Heating was easily obtained, but it took the ingenuity of Willis Carrier one hundred years ago to add cooling to the moved air.

Tempered air in traditional sealed buildings usually follows this path: air is drawn into a plant room on the roof (or on a middle floor), heated or cooled there, then forced by fans through ducts down the ironically named risers, along ceilings to be distributed through grilles. The air returns through a separate set of ducts (or more commonly a ceiling plenum) to the plant room where some is recycled (to save the thermal conditioning) and some is vented out.

In most hotels the supply follows this pattern, but the many small rooms make it difficult to collect and return the air. Rather it is exhausted in several ways: drawn out through the bathroom fan (the quiet hiss you hear when cleaning your teeth), lost through gaps in windows (where it helps prevent leaks) and some may be vented back into the corridors where it helps to condition that space before it is ducted back to the plant room.

This system of returning air via the corridors was common in the 70s, at the time of the Tri-Arc, (and is in use in the Camperdown version) but is not commonly used now because there are concerns about noise and fire safety for the vent coming through the wall. Take another look at the Tri-Arc plan and the issue of ‘dead ends’, and possibly dead air, is clear. The assumption then is that the issue of contamination in Melbourne was a result of transmission across the corridor space.

I suspect that the super-efficient plan developed by Travelodge is a very cost-effective arrangement for a hotel but is not a ‘fit-for-purpose’ design for a 21st century quarantine hotel. But this is only speculation (without being able to visit the Holiday Inn), and the current inquiry may prove me wrong. But let me be clear: I don’t think there is a particular fault here, rather I think using hotels for quarantine was a bad idea from the start, irrespective of the AC system used.

There are two better options: sealed hospitals with AC systems that are pressurised to prevent contamination; or fully fresh air ventilated buildings. Notably Victoria’s Dan Andrews, who advocated hotel quarantine when Scott Morrison had no plan, (but so many suffered from bad management of that decision), is now planning to build a purpose-built quarantine centre with fresh air paramount. How very Aussie: a quarantine hotel made of dongas. A victory for passive design.

Two more Tri-Arc stories to end: the early Travelodge hotels in Australia were developed by Charlotte and Ervin Vidor, immigrants from Poland and Hungary in the 60’s. They went on to found Toga Hotels and now have the brands Vibe, Medina, and Adina (which is explored in my chapter “The Migrants Who Built Modern Sydney” in The Other Moderns, edited by Rebecca Hawcroft and published in 2017 by New South).

And finally, the image here of the Darwin Travelodge, with brick panels missing, was taken a week after Cyclone Tracy when I worked briefly as a BLF volunteer putting roofs back on houses. It was remarkable to find the building, one of Darwin’s largest as I recall, that had withstood the fury amongst the devastation everywhere. I didn’t stay there at that time unfortunately – rather I was sleeping on the science bench in Nightcliff Highschool - but that’s another story for a future column.

Tone Wheeler is principal architect at Environa Studio, Adjunct Professor at UNSW and is President of the Australian Architecture Association. The views expressed here are solely those of the author and are not held or endorsed by A+D, the AAA or UNSW. Tone does not read Instagram, Facebook, Twitter or Linked In. Sanity is preserved by reading and replying only to comments addressed to toneontuesday@gmail.com

Tone Wheeler

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