Technical Terms


This is an abbreviation for Heating, Ventilation and Air Conditioning. It covers all air conditioning from high rise buildings through to residential systems. It is across all areas of modern life through retail, commercial and industrial applications. It includes a variety of equipment for heat transfer & air movement to facilitate the supply of clean, temperature controlled air to an occupied space.



This is a build-up of particles which appear below the grilles or registers. It is commonly noticed on clean sheets of paper or flat surfaces. It can be from internal contamination or a breakdown of internal components.  In the case of exhaust systems it can be from a build-up from exhausted materials. This Fall-out should be collected to aid in the investigation of the cause.


By definition Mould is a fungi with a mycelial (filamentous) type of growth. While they are present in outdoor air they are of a greater concern in indoor environments with the potential to affect human health. Mould needs 4 items to grow – Moisture, a suitable Temperature range, Nutrients and Spores. The spores occur naturally in the ambient air. The other 3 items are all present in a HVAC system.


Indoor Air Quality