Situation

A Brisbane CBD workplace incurred water leaks each time heavy rain occurred. Carpet was dried and ceiling tiles affected were replaced. There was no visible signs of mould however, given the number of times water leaks have occurred and the severity of some events client requested inspection. MCS recommended sampling to be incurred which is the best means to assess indoor air quality since no visible mould exists which was accepted by the client.

Sampling

Sampling was organised before 7.00am which is the time when the air conditioning system commences and when staff start to arrive.

Air sampling was conducted first using a calibrated Bio-pump to draw surrounding air into the outlet at 15 litres per minute where it operates for 5 minutes. An air-o-cell is attached to the inlet which is a unique air sampling cassette specifically designed for the rapid collection of a wide range of airborne aerosols including mould spores. The Air-O-Cell® collects both viable and non-viable sample specimens, providing a much broader overview of potential allergens contaminants than conventional sampling techniques.

 

The Air-O-Cell® operates upon the principle of inertial impaction. Particulate laden air is accelerated as it is drawn through the cassettes tapered inlet slit and directed towards a small slide containing the collection media, where the particles become impacted, and the air flow continues out the exit orifice. The adhesive nature of the collection media prevents the collected particulate from blurring or being washed off during the laboratory staining process, and eliminates sample loss from vibration during handling and shipment.

After sampling is completed, the cassettes are sent to a laboratory, where the slides are removed and direct microscopic analysis can be immediately performed.

This test was performed in two office locations and one outside in order to obtain the background level of mould. It takes 3-5 working days to receive the report from our Mycologist where it revealed the air quality was within normal mould ecology level.

Inspection

During the inspection process, the carpet was found to be wet under one work-station using a hydrosensor. Upon close review mould was just visible on top of the carpet fibres which was uplifted and disposed due to visible mould underneath this work station. Area was treated and carpet taped down to prevent any trip hazard.