Obstacles that prevent air flow to and from vents will reduce the efficiency of the sub floor ventilation system.
Sub floor vents spacing.
Of the australian standards a s.
3600 specifies that the minimum requirement for sub floor ventilation should be one 1 ventilator of 8 400 mm.
Their size and spacing depends on the design of the vent and the amount of air it allows through.
Vent type l vent size l area per square mm.
The general australian standard requirement for the spacing of air vents is that they should be placed within 600 mm of corners and be spaced evenly around the perimeter walls of the building.
Landscaping should not limit air flow around the external perimeter of the sub floor space and structural elements should not limit air flow.
Terracotta 230mm x 150mm 6 200vent in situ.
A minimum of five air changes per hour should be provided and double that for wet subfloor spaces.
The sub floor space must be free from all building debris and vegetation.
The space under a suspended timber framed floor must be ventilated.
A clear opening area of 3500 mm 2 100 x 35 mm should be provided for every square metre of floor area.
Table 3 4 1 1 specifies the minimum amount of subfloor ventilation openings and height of subfloor framing members above ground level for the three climatic zones illustrated in open link in same page figure 3 4 1.
The table allows subfloor ventilation rates to be halved if the ground within the subfloor space is sealed by an impervious.
Openings should be provided within 750 mm of corners and evenly spread.
Aleta 230mm x.