Hotel quarantine outbreaks prompt ventilation review

The Victorian government is conducting a review of hotel ventilation and air conditioning systems amid an increase in COVID-19 cases linked to quarantine. The situation has raised further concerns about the suitability of hotels as quarantine facilities, and the role of airborne transmission in spreading the virus.

The Australian hotel quarantine system has registered outbreaks in Adelaide in November 2020, in Brisbane in January, and in Perth and Melbourne in February. In the past week there have been several cases of COVID-19 transmission across three Victorian quarantine hotels, including various cases of the more infectious UK strain. There has also been a confirmed case of guests in one room contracting an identical strain from guests in a separate room – pointing to some form of airborne transmission.

Emergency Services Minister Lisa Neville has said the “working assumption” was that the viral load of one group was so high, the virus had travelled through the hotel corridor when the guests had opened their doors for food or laundry services. More recently, Chief Health Office Brett Sutton speculated that a nebuliser used by a guest may have led to another incident of transmission.

Authorities are now conducting a complete review of hotel air conditioning and ventilation.

What can HVAC&R experts tell us?

Commonplace air conditioning and ventilation design in high-rise hotel rooms consists of a fan coil unit over the entrance area or bathroom supplied with outdoor air introduced via openable windows, or ducted down the corridor. Air is exhausted from the bathroom and, because exhaust generally exceeds supply, this creates negative pressure in the room.

However, there are a host of factors that may cause air in the room to mix with air in a corridor when the door is opened.

Simon Witts, M.AIRAH, is principal engineer for LCI consultants and worked with the Victorian Health and Human Services Building Authority (VHHSBA) on the engineering guidelines for healthcare facilities released last year. He notes that hotel rooms may have net negative airflow, but this is very different to negative pressure systems rooms found in hospitals.

“There are many factors involved in whether air moves between two spaces,” says Witts. “For example, thermodynamic differences. If someone has their room at 18°C and the corridor is at 24°C, cold air comes out at the bottom of the open door and is replaced by warm air at the top.” He adds that this would depend on the magnitude of temperature differences.

Witts also notes that airflow within the rooms may be affected by a closed door to the bathroom, or even more radically by an open window or balcony.

“If we’ve got COVID-19 positive people in a room with a balcony, I wouldn’t want to be on the same floor,” says Witts.

Additionally, Australian Standard AS 1668.2 limits the negative pressures to 12Pa to prevent contaminants coming from undesirable locations when the source of makeup to the bathroom exhaust is incorrect. This will not be enough to stop air mixing when the door is opened.

Finally, Witts stresses that all hotels will be different.

“Buildings are a dynamic beast. Different system designs, ages and different construction mean the façades leak at different rates, which also affects the mixing of air between rooms and corridors.”

Fit for purpose?

Given the growing list of outbreaks, some have questioned whether hotels are appropriate for quarantine facilities.

Brett Fairweather, M.AIRAH, a mechanical engineering consultant from It’s Engineered, echoes those concerns.

“Any adaption of a hotel to provide quarantine capabilities will be a compromise to some extent, and limitations are likely to be specific to each building,” he says. “These facilities were built as hotels, not quarantine facilities. As I’ve said to a few people lately, my bicycle also performs poorly as a boat.”

Fairweather suggests that a new classification for quarantine facilities might fit well somewhere in the National Construction Code.

He also points out that hotel systems may not be working as intended.

“Experienced HVAC practitioners would be aware that if the design, commissioning and maintenance of a hotel room’s bathroom exhaust did not prevent the exhaust air from being replenished from the corridor, then there is a high likelihood that contaminants from the corridor would be drawn into a hotel room – potentially including SARS-CoV-2.

“Initial commissioning and ongoing maintenance of hotel exhaust systems are often lacking,” he says. “Getting this up to scratch should be a starting point in any project. It will improve the chances of expected outcomes following the introduction of other supplementary measures. Experienced HVAC practitioners are likely to have good advice to support owners in these endeavours.”

Although the current Victorian review is looking at both ventilation and HVAC systems, there is a significant difference between them. Centralised HVAC systems, commonly found in hotels, condition and transport air through a system of vents, ductwork, filters and other obstacles that would be more likely to trap particles. At this stage, there are no confirmed cases of COVID-19 spreading through such a system.

Premier Daniel Andrews, when asked whether hotel quarantine was in fact viable given the recent cases, would only recognise that there are challenges.

“Hotel quarantine if we are indeed dealing with a hyper-infectious aerosolised virus, an airborne transmission challenge, is very very difficult,” said Andrews.

7 Replies to “Hotel quarantine outbreaks prompt ventilation review

  1. Thank you for this article, it echoes my comments made on the AIRAH Linkedin page this afternoon. Really the only solution is to use single storey buildings – such as an old style motel, where the rooms open onto a courtyard, or car park.
    Regrettably there are very few of these left near to a major COVID hospital. Which seems to be one of the Government’s pre-requisites.
    Gordon Sandor
    Original Safe T Air

    1. Build one. This quarantine regime will be there for at least 3 years if not more. With the current quarantine regime you will this scenario will play out many times at enormous economic, health and emotional cost.
      Having quarantine hotels in the middle of the city and these hotels being unsuitable ois like jhaving fire in your lap and hope you won’t catch fire. Plain common sense. Go to how Australia quarantined during the past epidemics.

  2. We cant do much to existing buildings even if we try to increase the FA to any building by 25% and EA by 50% which 1 : 2 will be heavy load on the system and design conditions, I agree with Gordon and Rama.
    We should be thinking of building a centralised quarantine hub with 100% fresh air HVAC units designed for this purpose for whole country.

  3. Rama, your comments are bang on. The government needs to design and build a purpose built facility immediately, and stop trying to make do with what the hotels can provide. The health and financial costs have been severe and will no doubt repeat in not implemented.

  4. Yes, my experience with the SARS crisis in Beijing in 2003 showed that the high rise hospitals (yes, hospitals, not your average hotel high rise) were a long way short in desired air pressure differentials. I determined this by the use of Draeger smoke tubes which clearly showed air currents (drafts) rising alongside plumbing pipes at en suites, gaps around power points, and drafts under closed doors. It had beaten the health authorities there, including WHO, as to how a person in a hospital on one floor could acquire SARS from a serious SARS patient on the floor below or even two floors below. With the smoke tubes, easey peasey. the most successful hospital was a single storey one built of sandwich panels in a single week, complete with all power and X-ray machines; the lot. It comprised a ducted tempering system that sent conditioned air along ducts at corridor ceiling level and supplies to all rooms. Each room then had a simple exhaust fan operating continupisly. All at negative pressure relative to the supplies but able to exhaust all air as changes to that outdoors for dispersal. In this simple hospital built for 1,000 patients not a single case of nosocomial transmission occurred nor, incidentally – though involving other protective factors, did any medical staff contract SARS there. This compared with the glitzy hospitals that saw around 500 medical staff contract SARS and 49 died. In the single storey facility, not a one. To take this further the mining camp concept is best. That is single use stand-alone demountable buildings perhaps even with verandahs. So occupants of a unit don’t get near to others. That’s the way to go. As per Howard Springs in Darwin.

    On the Beijing hospital experience I did prepare articles and they were published in Ecolibrium in 2003 and 2004. They didn’t highlight this stray air current story especially although it is described in passing. For our times I believe all this is critical to successful design of these premises. They need to be engineered.

  5. As a fire engineer I’ve analysed many hotel and unit buildings with reference to air and smoke flow.
    Whilst the HVAC systems differ in these two building types, there is a common use of toilet exhaust – a system usually poorly designed and rarely maintained. As indicated in this article, the most usual air conditioning system in hotels is a packaged re-circulation system at the entrance with cooling coils from a central chiller unit and heating by a local electrical heater, both within the ducted discharge. Fresh air is drawn through openings in the room, under and over the door and when the door is opened on a frequent basis. This ventilation is effected by the toilet exhaust system and if the ducting / register is blocked, there will be no fresh air by this means. In most hotel occupancies this fresh air supply is statistically adequate for transient guest movement.
    Without adequate ventilation, occupants will be in a closed cycle area with virus contamination of the packaged system filters built up over time.
    As soon as openable windows or balconies are present, there is a massive increase in power demand for the chiller or heater system – see later comment on costs.
    Interestingly corridor ventilation is often either positive supply or negative exhaust, often relying on make up or exhaust via gaps in room or stair doors. Sometimes static ducting is provided for negative corridor ventilation. Note that the room doors, whilst being fire doors, have no requirement for smoke seals – thus allowing contaminated air flow (and smoke flow in my studies), with negative corridor pressure possibly contaminating the corridor!
    One further issue is the need for stair pressurisation in buildings >25m effective height! The relationship between guest room and corridor ventilation both drives and complicates the pressure differential between the corridor and stairwell under both fire and non fire conditions
    Ultimately hotel guest room air conditioning and ventilation is driven by cost, and the current packaged systems meet this requirement as evidenced by the “key card slot” that shuts the room system down as the guest leaves the room.
    My web site includes two papers that might be of interest, the first concerning smoke flow through fire doors installations and miscellaneous mechanical ventilation systems in buildings – especially how some poorly designed toilet exhaust systems are poorly designed and maintained.

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