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Subfloor ventilation and sub-floor ventilation installation practices from Envirofan

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Subfloor ventilation and sub-floor ventilation installation practices without the use of flexible ducting from Envirofan.  

The purpose of home ventilation system is to maintain a healthy living environment by supplying fresh air to home, while at the same time removing stale and humid air from habitable and subfloor areas.

The answer to effective subfloor ventilation is in the installation practices performed. Let us look at the sub-floor area itself. We can liken it to a blank canvas board as used by an artist, the more brush strokes, the more detailed and busy the canvas becomes.

When it comes to sub-floor or subfloor ventilation installation practices the more materials that are used in the subfloor area the more inhibitive air flow becomes, as the air has to travel around obstacles.

Let us look at the worse case scenario, that of plumbing systems e.g. Bladder tanks for rainwater storage, drainage pipework and central ducted heating. Ducting and pipework range from 100mm to 300mm. When these ducts are installed, this could lead to sub-floor ventilation problems, as the air flow can be inhibited.

If the house is of solid brick construction another subfloor ventilation obstacle exists, that of sub-walls. Ventilation companies are called in to rectify this problem by installing more flexible ducting. In some cases, penetrate through these subwalls to accommodate the ductwork usually of 150mm or 6 inches, which means the penetration has to be larger to accommodate the duct itself. If they do not make these penetrations, then they usually run the ductwork through an established opening under doorways. Therefore, we are still left with the legacy of the ductwork under the home, which inhibits sub-floor ventilation, as compared with Envirofan’s approach to subfloor ventilation installation practices.

Another consideration with the use of ducting in sub-floor ventilation situations is that in-line fans as shown below, incur a back pressure drop, as the air is pulled through the duct. Therefore, the efficiency of the in-line systems is marginally lost.

When sub-floor clearance are reduced in line with Australian Building Code guidelines at the minimum clearance of 300mm, installation of flexible ducting causing airflow obstructions may be unnecessary. Envirofan approaches this particular situation quite differently from orthodox subfloor ventilation methods.

Flexible duct has been used in the sub-floor ventilation industry for years, however, if alternative subfloor ventilation installation practices deliver a better result should it not be considered?

Envirofan’s sub-floor ventilation approach is cutting edge. When Envirofan starts with a blank canvas, Envirofan finishes with one. This is to maximise effective cross-flow in underfloor and sub-floor areas without obstructions.

Firstly, Envirofan can induce dry air from the outside, and force it into the underfloor and sub-floor area by the use of solarpowered ventilation systems, which is installed on the exterior wall, or by the utilisation of wire mesh vents. Envirofan then uses bricksize sub-floor ventilation systems that are established in the subwalls to direct air flow from room to room at a rate of 2.5m3/perinute at 27db. Then extraction sub-floor ventilators are mounted on the exterior of the wall, preferably on the east or southern aspects which draw the damp air out. This is the objective of what is deemed cross-flow ventilation. This is Envirofan’s objective to reach effective sub-floor ventilation. In exceptional circumstances, whereby there is no accessible exit point for an extraction system, the use of flexible duct to a near external point is unavoidable and is used sparingly.

For optimum effectiveness in sub-floor ventilaton, keep sub-floor clear and the use flexible ducting to a minimum.

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