History of poor indoor air quality
For our next project we attended a hospital based in Nottingham and were tasked with undertaking a building inspection and microbiological sampling in the water treatment plant room at the hospital. The water treatment plant room within the Hospital is home to several water treatment tanks and treatment agent storage vessels. The water treatment vessels are enclosed however, several overflow faucets discharge water into open drainage. The drainage is generally enclosed and located below the plywood floor elevation. Some of the equipment in the room produces hot water vapour which contributes to relatively high humidity in the room. On our inspection the room was currently not equipped with passive or active ventilation in order to control water vapour.
Identifying moisture within the building
Our surveyor carried out moisture mapping using a Hydromette HB30 moisture meter and a Tramex Moisture Encounter Plus. As a result of moisture mapping our surveyor found elevated levels of water moisture within the plasterboard panelling. Due to this there was also evidence of mould contamination present on plastic pipework and the top surfaces of the water treatment cylinders which indicated surface water condensation. The extent of mould contamination in this room is approximately 15m2. The results of the microbiological air sampling showed significantly elevated concentration of fungal spores and fragments in the indoor environment. The identified fungal species such as Penicillium/Aspergillus, Cladosporium, Chaetomium and Stachybotrys are all closely associated with water damage in building and long-term water saturation of building materials. The identified species are also considered highly allergenic in some sensitive individuals.
Recommendations to improve indoor air quality
Our surveyor then concluded that the high humidity in the room is a result of open discharge faucets of water in the treatment plant. This produces water vapour in the room which then condenses either on the cold areas of the walls or on the cold surfaces of the plastic pipework and water treatment cylinders. This condensation of water on the surfaces of the equipment and walls creates favourable conditions for fungal growth. The overall indoor air quality in the plant room was considered poor as the extent of fungal contamination is approximately 15m2. Our surveyor concluded that the overall risk to health from exposure to fungal elements was likely to be high, so strongly recommended that this fungal contamination was removed using suitable methods such as localised and area air filtration, sanitation of contaminated surfaces and application of antifungal treatments. It was also recommended to control the humidity within the room by installing passive ventilation grills to the front and back doors in the plant room.