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Understanding the Conditions in Under-Heated Problem Dwellings 10 slides max!! Joseph Little - BArch, MRIAI, MSc Archit. AEES.

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Presentation on theme: "Understanding the Conditions in Under-Heated Problem Dwellings 10 slides max!! Joseph Little - BArch, MRIAI, MSc Archit. AEES."— Presentation transcript:

1 Understanding the Conditions in Under-Heated Problem Dwellings 10 slides max!! Joseph Little - BArch, MRIAI, MSc Archit. AEES

2 10 slides max!! There can be four parties responsible for problem dwellings: 1) The builder/developer - who may have wanted too high a profit, or set too small a budget to do a good job, may have hired an inadequate team, & may even have wanted corners cut 2) The design team - which may have agreed too low a fee to do the job properly, may have resourced the project inadequately and inspected it insufficiently, or been compromised in their role by the very nature of the builder/developer model 3a) The careful occupant - who faced with a badly-built apartment responds by turning the heat down (Im damned if I waste further money) and switches the intermittent fan to manual control, or 3b) The unthinking occupant - who blocks vents, frequently dries clothes in small rooms and (perhaps) likes lots of stews! Too often the whole problem is blamed on the occupant 4) Lastly the government - which has under-resourced building control for over two decades, and has unwittingly allowed inadequate guidance, like Part F (ventilation), to negatively effect the air quality of the homes of thousands of families PROBLEM DWELLINGS

3 10 slides max!! To deal with the physical conditions that help create fuel poverty we have to analyse what happens in problem dwellings. What prevents even & adequate air & surface temperatures? Quality of construction, insulation continuity & airtightness Heating equipment (location and specification) Heating regime What prevents ventilation maintaining low humidity & good air quality? Quality of construction, window & background vents design Extract ventilation (type, spec. and location Ventilation regime PROBLEM DWELLINGS

4 10 slides max!! To deal with the physical conditions that help create fuel poverty we have to analyse what happens in problem dwellings. What prevents even & adequate air & surface temperatures? Quality of construction, insulation continuity & airtightness Heating equipment (location and specification) Heating regime What prevents ventilation maintaining low humidity & good air quality? Quality of construction, window & background vents design Extract ventilation (type, spec. and location Ventilation regime This presentation focus on conditions in one boom-time apartment, only 5 years old. It is not the worst case, but it is instructive Often, not always, occupant issuesRelated to the other three parties PROBLEM DWELLINGS

5 Living area Kitchen Corridor Entrance door Bathroom Bed #1 Bed #2 Hall north THE APARTMENT

6 ITS STRUCTURAL PROBLEMS

7 moist air thermal bridge moist grout in pre-cast wall

8 Electrical convection heaters in bedrooms Storage heaters in hall and Livingroom The area where heat is needed most to deal with surface condensation & thermal comfort Heat sources in middle of plan INADEQUATE HEATING

9 Heating regime roomsPattern of usage storage heater Living / kitchenUsed to heat & store all year HallRarely on Elec convector heater Bedroom #120 min. per day in Winter Bedroom #2Never on Occupant comment about electrical convector heaters: I hate using them, theyre just too expensive

10 INADEQUATE HEATING Heating regime - Visit on 9/12/ °C °C 17.8°C 49.3 %RH 15°C 17.5°C °C 16.5°C 16-17°C 14°C 11°C 12°C 14°C 18.5°C 18.7°C occupant is gaining heat from neighbour! Heat loss & thermal bridges along external envelope B#1 Hall K L

11 Kitchen extract duct (6.5 – 7m) Bathroom extract duct (6.5 – 7m) Duct runs this long, especially when shallow (i.e. 25 x 300mm) create much resistance INADEQUATE VENTILATION Intermittent extract fan with 5 minute over-run

12 Logged data from bathroom of apartment - 25th July – 11th August 2011 Moisture content of air (g/Kg of air) Temperature (°C) When showers arent daily this appears to be base moisture content 90% increase in moisture content Even after 24 hours ventilation does not return to baseline Temperature quickly returns to normal INADEQUATE VENTILATION From a health point of view it has been recommended to maintain the relative humidity below 45% for some time each winter to reduce the dust mite population. At 22°C this corresponds to 7 g water vapour per kg air (ref: Korsgaard J. (1983)) 10

13 51.5 Pa ~22 l/s In order to minimise ceiling heights (& extra cost to developers) ducts for fans were typically 300 x 25mm. These have 4 times resistance of ducts 204 x 60mm It appears the bathroom extract was sized to meet the min. flow rate of 15 l/s. We calcd ~ 51.5 Pa static pressure due to length & type of ducts, bends & grille 22 l/s suggests an allowance of 40% was added to 15 l/s However, whether due to too small a flow rate, too short an over-run or restrictions in ducts, this system is not delivering healthy conditions IMPROVING VENTILATION

14 Note: DEAP assumes 0.5 ACH is delivered through infiltration & ventilation We have followed old guidance from the UK - other countries have far more specific and onerous ventilation requirements : we suggest revision is needed A big difference in requirements is evident comparing standards from elsewhere (USA, France, Australia, etc) In France, Poland Germany they have used humidity- triggered ventilation systems for many years – these ventilate till humidity levels are low and healthy Aereco, Glidevale iMEV, Lunos are some of the systems

15 Kitchen extract duct (6.5 – 7m) Air rises vertically in passive stacks Revised Regs (TGD F-2009, ) for single-sided apartments requires low & high level openings, or openings & passive stacks to rear IMPROVING VENTILATION

16 Unless we understand what are the causes of the various, & often inter-related, issues in a problem dwelling we will not solve this part of the fuel poverty triangle IN CONCLUSION We need: Far more rigorous examination of the causes of problem dwellings Like the Stamford Brook studies in the UK we need all parts of the construction industry to understand their part in what goes wrong Could a conference focus on this issue specifically? We need changes to guidance (like Part F) so that minimum standards support healthy conditions We need properly resourced building control Thousands of tenants of social housing & owners of boom-time dwellings are experiencing conditions that they may, or may not, be exacerbating but that they did not create They need our support Thank you

17 10 slides max!! Joseph Little - BArch, MRIAI, MSc Archit. AEES


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