HEATING, VENTILATION & SERVICES 59
Designed-in air quality V
entilation plays vital role for ensuring occupants’ health within a home, and getting the right system in place at the design stage is essential. There are many forms of ventilation available currently for the residential market, but a number of factors influence the selection process.
Approved Document F of the Building Regulations states that an “adequate means of ventilation,” must be provided, but since the update to these Regulations in June 2022, there are now three types of ventilation identified (it was previously four, but passive stack ventilation was removed). The ventilation types identified in the new Part L are as follows: • Less airtight dwellings: natural ventilation with background ventilators and intermittent extract fans • Highly airtight dwellings: continuous mechanical extract ventilation (MEV) and mechanical ventilation with heat recovery (MVHR).
A highly airtight dwelling is defined as that with a ‘designed’ air permeability lower than 5 m3
/ (h·m2 air permeability lower than 3 m3/(h·m2
) at 50 Pa, and an as-built ) at
50 Pa; and dwellings are assumed to have an infiltration rate of 0 air changes per hour. For less airtight dwellings, there is an element of mechanical ventilation within the ‘natural ventilation’ option, which can make things a little bit misleading. However, a less airtight dwelling is defined as: a design air permeability higher than 5 m3
/(h·m2 /(h·m2 ) at
50 Pa; an as-built air permeability higher than 3 m3
) at 50 Pa; dwellings are
assumed to have an infiltration rate of 0.15 air changes per hour.
The changes in classification indicate the Government’s intention to make sure that in future, homes are provided with adequate ventilation and have increased ventilation rates. With the Future Homes Standard being implemented in 2025, the need to build homes with more efficient energy consumption, and therefore more
ADF MARCH 2023
airtightness, poses a question for designers about what mechanical ventilation system to put in place.
MVHR: an energy-efficient solution The most efficient use of energy and utilising heat recovery to achieve air quality is mechanical ventilation with heat recovery (MVHR), which is suitable for houses, flats, or apartments. MVHR works by combining supply and extract air, extracting moisture-laden, stale air from wet areas, such as kitchens and bathrooms. The heat from the extract air is recovered by the heat exchanger in the unit, and is recycled into the supply air entering a dwelling. A MVHR unit can be located in a number of areas, such as the ceiling void, loft, cupboard, or garage. Designed to recycle up to 92% heat and utilising low powered electronically commutated (EC) centrifugal motors, it is a system that ticks all the boxes for futureproofing homes. Ideal for lowering Dwelling Emission Rate ratings, the performance of MVHR
If a MVHR system is added to a design early, it is easier for the aesthetics of the building to absorb the system’s layout
The new Part F raises the bar for domestic ventilation, given the need to ensure air quality in more efficient house constructions. Lee Caulfield from Titon explains further
WWW.ARCHITECTSDATAFILE.CO.UK
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 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76
