search.noResults

search.searching

saml.title
dataCollection.invalidEmail
note.createNoteMessage

search.noResults

search.searching

orderForm.title

orderForm.productCode
orderForm.description
orderForm.quantity
orderForm.itemPrice
orderForm.price
orderForm.totalPrice
orderForm.deliveryDetails.billingAddress
orderForm.deliveryDetails.deliveryAddress
orderForm.noItems
to IAQ


engineering controls should sit above measures that rely on human behaviour such as distancing and wearing face coverings in any “hierarchy of risk control”.


“We don’t have all the answers, but we do know we need to ventilate better,” she told a recent BESA webinar. “This is not just about flow rates as it depends on the size of the space. 10 litres per second per person is the ideal, but if people are close together and for an extended period, we may need more flow rate. You can also have quite a lot of people in a large space with lower ventilation rates.”


Dependent


“The spaces that worry me the most are those that are naturally ventilated as these are temperature and wind dependent…they often rely on opening doors as well,” explained Noakes, who is professor of Environmental Engineering for Buildings at the University of Leeds and has also been providing advice on airborne transmission to the NHS during the pandemic.


The key factor with an engineered mechanical ventilation approach is that it can give you control over the air movement. The paths taken by air is critical and will be different depending


on the layout of the space and the occupancy levels. Displacement ventilation, for example, was shown to be effective in removing viral loads by a Cambridge University study during the pandemic, but it might not be effective in every situation.


“To protect schools and equip them for the future, we need to keep this simple and low cost,” said Nathan Wood. “There are around 24,500 schools in the UK and only a fraction have any real control over their ventilation. Even some of those with bigger budgets have ended up with highly sophisticated mixed systems that don’t work properly because they were poorly designed or badly maintained.


“As Professor Noakes has shown, we need a series of bespoke but


affordable solutions to crack this problem and the ventilation industry is working on it – but it will require investment from central and local government to give schools the support they need.” Domestic mechanical ventilation with heat recovery (MVHR) systems is another option that could be an effective retrofit solution. They offer localised control at minimal energy use due to their heat recovery function. More are also being adapted to include air cleaning technology. Ventilation manufacturers and specialist contractors are working on other low cost engineered solutions that are long overdue but have not yet been produced on any great scale for schools because of low demand (no budget).


“Before the pandemic, local authorities were facing growing community pressure to address the air quality issues around school buildings caused by traffic pollution. Now, in the wake of Covid-19, the focus has moved inside and, if we want people to feel more confident about returning to any communal building, then this issue needs to be properly addressed,” added Wood.


www.heatingandventilating.net April 2020


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36