Case Study 1: Indoor Air Testing

Brisbane commercial offices – offensive odour assessment.


The client's offices were located on an upper floor in a high-rise building in Brisbane's CBD. Office staff reported that the indoor air possessed an offensive, sewage-like odour, which had persisted for over two years. The odour was considerably greater after office hours and on weekends, when the HVAC system was turned off. It also seemed to linger and be concentrated in a particular corner of the building.


The Solution.


BELL Laboratories launched a thorough investigation and air analysis. We conducted air sampling and air testing with the HVAC system both on and off, monitoring the condition.


Our investigation led us to a discussion with the building manager, which revealed that there was a stand-alone air conditioning system servicing the boardroom. This was near the most heavily affected area.


An inspection of the ceiling cavity uncovered a drain that was feeding into an open tundish. It was assumed that the drain connected the stand-alone air conditioner to the sewer on the street below. It was also clear that the offensive odour was stronger in the ceiling cavity, suggesting this was the origin of the smell. The sewer below was affecting the indoor air quality via the open tundish.




We simply flushed out the trap with tap water to observe the effect on the odour. The odours quickly dissipated and no further problems were reported.


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