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

Understanding the Conditions in Under-Heated Problem Dwellings

10 slides max!!

Joseph Little - BArch, MRIAI, MSc Archit. AEES

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 (“I’m 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

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 & airtightnessHeating equipment (location and specification)Heating regime

What prevents ventilation maintaining low humidity & good air quality?Quality of construction, window & background vents designExtract ventilation (type, spec. and locationVentilation regime

PROBLEM DWELLINGS

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 & airtightnessHeating equipment (location and specification)Heating regime

What prevents ventilation maintaining low humidity & good air quality?Quality of construction, window & background vents designExtract ventilation (type, spec. and locationVentilation 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 issues Related to the other three parties

PROBLEM DWELLINGS

Living area

Kitchen

Corridor

Entrance door

Bathroom

Bed #1

Bed #2

Hall

north

THE APARTMENT

ITS STRUCTURAL PROBLEMS

ITS STRUCTURAL PROBLEMS

moist air

thermal bridge

thermal bridge

moist grout in

pre-cast wall

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 sourcesin middle of plan

INADEQUATE HEATING

INADEQUATE HEATING

Heating regime

rooms Pattern of usage

storage heater

Living / kitchen Used to heat & store all year

Hall Rarely on

Elec convector heater

Bedroom #1 20 min. per day in Winter

Bedroom #2 Never on

Occupant comment about electrical convector heaters: “I hate using them, they’re just too expensive”

INADEQUATE HEATING

Heating regime - Visit on 9/12/2011

42-30°C

45-119°C

17.8°C49.3 %RH

15°C

17.5°C

17-18

23-21°C16.5°C

16-17°C

14°C11°C12°C14°C

18.5°C 18.7°C

occupant is gaining heat from neighbour!

Heat loss & thermal bridges along external envelope

B#1

HallK

L

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

Logged data from bathroom of apartment - 25th July – 11th August 2011

Moisture content of air (g/Kg of air)

Temperature (°C)

When showers aren’t 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

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 calc’d ~ 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

IMPROVING VENTILATION

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

Kitchen extract duct(6.5 – 7m)

Air rises vertically in passive stacks

Revised Regs (TGD F-2009, 1.2.2.12) for single-sided apartments requires low & high level openings, or openings & passive stacks to rear

IMPROVING VENTILATION

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 thatminimum standards support healthy conditions

We need properly resourced building control

Thousands of tenants of social housing &owners of boom-time dwellings are experiencingconditions that they may, or may not, be exacerbating but that they did not create

They need our supportThank you

10 slides max!!

Joseph Little - BArch, MRIAI, MSc Archit. AEES

[email protected]