INDOOR AIR QUALITY FOR HOTELS
LEIGH ROBERTSON
T
he Hotel industry has unique issues when dealing with indoor air quality. This article will explore some of those issues that Hotel engineers must consider when planning budgets, and considering planned maintenance regimes. The article will look at: 1. Indoor air quality vs. Energy efficiency 2. HVAC hygiene/condition 3. L egionella – Cooling towers not the only source
4. Proactive approach to indoor air quality
INDOOR AIR QUALITY (IAQ) VS. EFFICIENCY Traditionally, as buildings became more and more airtight in an endeavour to maximise energy conservation, complaints arise about the quality of the indoor air. Experience has shown that if a certain minimum amount of outdoor air is not taken into a building during times of occupancy, all indoor pollutant levels rise, including the carbon dioxide exhaled by all building occupants. Standards Association of Australia and ASHRAE have a minimum ventilation rate for different spaces, as per A.S.1668-2-2012 and ASHRAE 62.1-2013. A study undertaken in the US highlighted that with minor adjustments and technology, such as energy recovery and night re-cooling in extreme climates, energy efficiency can be achieved without compromising the overall indoor air quality. (US EPA “the study suggests that protecting indoor environmental quality in energy efficiency projects need not hamper
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the achievement of energy reduction goals, provided that the projects are instituted wisely. Avoiding measures that could degrade IEQ involved energy sacrifices that were small compared to the potential for energy savings from measures that are compatible with IEQ.”) Every year brings significant advances in these types of “sense, command and control” systems. Finer and more intelligent control of building operation systems will certainly save energy, improve client satisfaction and maximise buildings potential for maintaining IAQ. HVAC maintenance, which I will cover in more extent later, can also both improve efficiency and improve overall indoor air quality. IAQ and energy conservation are interdependent and both should be given the same priority to ensure the health of building occupants. Striving for energy efficiency does not have to reduce overall indoor air quality.
Below are a few examples of poor maintenance of AHUS that Healthy Buildings International has encountered in inspections of Air handling units: Photo 1 Heat coils- Mould growth downstream of filters
Photo 2 Chill coil chamber – Mould growth downstream of filters
Photo 3 Condensate tray – Standing water and heavy corrosion that may harbour bacteria
HVAC HYGIENE/CONDITION The hygiene of the HVAC systems in all Hotels can also be a cause of poor indoor air quality. Standing water within condensate trays or chambers can be conducive to microbial growth. Dirt past the filters may spread bacteria and also create conditions conducive to microbial growth. Corrosion may affect the efficacy of the system and allow unfiltered air into system and block drains. Poor fitting filters, missing filters, undesirable soiling and unsuitable efficient filters can all affect the IAQ within Hotel common areas and when suppling outside air to fan coil units and the like to Hotel rooms.
Photo 4 Complete bank of missing filters, heavy leaf matter buildup may cause issue