To stop smells entering a building, the open end of the ventilating pipe should be at least three metres to the side of, or extended to 0.9m above, any opening into a building.
Er mwyn atal arogleuon rhag cyrraedd yr adeilad, dylai pen agored y bibell awyru fod o leiaf dri metr i'r ochr, neu yn ymestyn 0.9m uwchben unrhyw agoriad i'r adeilad.