There were areas within the occupied space that were found to have visual fungal growth. The building was found to be stuffy with a mildew type odour. In order to develop a scope air testing was conducted to check the levels of mould within the occupied space. In conjunction with the air testing the air conditioning system was inspected, there were high to severe levels of visual fungal growth found throughout the system. The airborne results returned a high result which increased the priority for the commencement of remediation within the building.
The building is a single storey establishment which operates 24/7. The building is predominantly sealed and is solely reliant on the air conditioning system for air distribution within the occupied space. There is only one air conditioning plant located in a dedicated plant room. The air conditioning is a small package unit with only one stage of cooling. There is an outside air fan distributing outside air directly into the ceiling space. The return air system is not ducted and is returned to the package unit via the ceiling space. The building is located in Northern Australia (BCA Zone 1).
In order to return the occupied space and associated air conditioning back to normal ecology (less than 1000 colony forming units) the following scope was developed;
- Total Ventilation Hygiene Pty Ltd (TVH) provides Heating Ventilation and Air Conditioning (HVAC) Mechanical Services along with Specialised Ventilation Hygiene Services nationaly, operating out of Brisbane, Darwin, Melbourne, Sydney, Regional New South Wales (Wagga Wagga and Tamworth), Perth, Port Hedland, Adelaide and Townsville.
- Outside Air Cleaning and Upgrade of Filtration
- Cleaning of Plant room
- Cleaning, Refurbishment and Application of Anti Microbial Treatments and Coatings to Package Unit
- Cleaning of Supply Air Ductwork and Application of Anti Microbial Treatment and Coatings
- Removal of existing flexible ductwork and installation of new flexible ducting (R 1.5)
- Local Mould Remediation of areas with visual fungal growth
- Detailed cleaning of all furnishing and contents
- Steam Cleaning of fabrics and carpets
The scope was completed with the building returning to normal ecology. The efficiency of the system was increased, due to this the set point of the package unit was turned down due to its ability to cool more effectively.
Filter Plenum Before
Filter Plenum After
Package Unit Before
Package Unit After
During the works it was evident that the package air conditioning does not have the ability to be able to control humidity within the occupied space. As the outside air is forced into the ceiling space it is placing hot/humid air into the ceiling space which mixes with the return air as it returns back to the package unit. Where possible, in areas of high humidly the outside air should be pre-conditioned or the space dehumidified. At the very least the unit should be able to have two stages of cooling to assist in removing moisture from air as it passes through the air conditioning system.
Supply Air Duct – Before
Supply Air Duct – After
Supply Air Duct – Before
Supply Air Duct – After
The predominant areas of visual fungal growth were found to be in close vicinity to moisture producing areas. Due to the growth on porous building surfaces these were required to be removed and replaced with new building materials. Wet areas should be identify and appropriate building materials should be used to ensure porous materials don’t become water damaged which are more likely to harbour mould growth.
Active Fungal Growth on Walls and Carpets
Active Fungal Growth Removed and Area Cleaned and Treated
During the steam cleaning of the carpet there were areas that were found to have active mould growth. These areas were found to be around where building occupants sit at their desk areas. As they come into the building in wet weather the water pools on the carpet protectors and the water makes it way underneath the carpet protectors. Due to this the elevated moisture provides an ideal environment for fungal activity.
Foaming Indicates Active Fungal Growth
Section of Carpet where Active Fungal was Identified
It’s important when conducting any mould works within a building that it is conducted according to the IICRC S520 International Best Practise Guideline. Once a mould event (outbreak) has occurred it is important that all items with the space are remediated or a detail clean is conducted (dependant on the severity of contamination) to ensure that the entire space can be brought back to normal ecology, pre-existing conditions before the fungal activity.
This project was directly supervised by a NADCA Air System Cleaning Specialist and IICRC Certified Mould Remediator.