How to assess correct level of ventilation
How to assess correct level of ventilation
ADEQUATE draught-free ventilation is the key factor for avoiding pneumonia, but how do you assess whether a building has the correct level of ventilation.
The quickest and surest way is to look for cobwebs, according to independent dairy consultant John Hughes. "Where cobwebs are present, there is inadequate airflow.
"Also look for drip marks on the wooden purlins because these indicate condensation problems. Both poor air circulation and condensation will lead to a build up of viruses and bacteria."
Hopper-style windows are also likely to result in poor ventilation, warns Mr Hughes. "Air hits the roof and is deflected down into the housing area, causing draughts."
Ridge caps on a building can also cause draughts as cold air descends into the building. What is needed is a chimney effect to suck stale air out, he explains.
This is achieved by having a gap of about 15-20cm (6-8in) under the eaves, with a board or upsweeping ventilators to direct air up along the roofing sheets.
Where a cap is placed above the ridge gap to prevent rain entering the building, make sure the gap is more than 10cm (4in), he advises. *