Thermal, Lighting, Acoustics

Question 1

The Chartered Institution of Building Services Engineers recommends what temperature range indoors?

Answer 1

19-23 degrees for internal temperatures, and less than 27 degrees in the summer.

Question 1

What environmental factors affect our lives in buildings? (7)

Answer 1

1. Thermal, 2. Moisture transfer and condensation, 3. Indoor air quality (dust, pollutants, co2) 4. Noise, 5. Lighting, 6. fire safety, 7. Water supply

Question 2

Thermal comfort assessment/scale

Answer 2

ASHRAE (american society of heating blah) has developed a 7 point scale for thermal environment, going from hot,warm,blah blah, to cool, cold.

Question 3

Predicted Mean Vote (PMV)

Answer 3

Professor Fanger (danish scientist) developed method to predict the level of satisfaction from the thermal comfort scale, using the predicted mean vote. Hot = 3, warm = 2, blah, cool = -2, cold = -3

Question 4

Predicted mean vote (PMV) and Predicted percentage of dissatisfied people (PPD) thermal comfort model

Answer 4

The PPD of people will be near enough 100 percent when the scale is at -3 or 3, but near 0 percent when the temperature is neutral. between 1 and -1 (slightly warm and slightly cool) lies the ‘comfort zone’. The area of this zone is above the U shaped curve of PPD, within the bounds of -1 and 1 on the x axis

Question 5

Adaptive thermal comfort model

Answer 5

People naturally adapt to their thermal envireonment, by making adjustments to themsevles or their surroundings. The PMV/PPD model does not always predict conditions in free-running (or naturally ventilated) buildings, though it’s acceptable in environmentally controlled buildings. This essentially says the acceptable indoor temperature should scale with the mean monthly outdoor air temperature. Hotter outside, more acceptably hot inside.

Question 6

Difference between PMV model and adaptive model for thermal comfort?

Answer 6

1. There is a difference in the application conditions, 2. The PMV/PPD model is acceptable in environmentally controlled buildings, but doesn’t predict as well in ventilated buildings. 3. Adaptive thermal comfort model should be used for naturally ventilated buildings

Question 7

Saturation

Answer 7

Saturated air is a sample that contains the maximum amount of water vapour possible at that temperature. If more water content than ‘saturated’ is in the air, water condensation occurs

Question 7

Condensation

Answer 7

The process whereby water is depsosited from saturated air

Question 8

Surface condensation

Answer 8

When condensation occurs on visible surfaces within the building

Question 9

Interstitial Condensation

Answer 9

condensation occuring within or between the layers of the building envelope

Question 10

Control of moisture transfer in buildings (8)

Answer 10

1. Natural or mechanical ventilation, 2. Use of de-humidifiers, 3. Insulation of cold surfaces IE pipes, 4. Increasing air temperature, 5. Removing sources of moisture EG drying clothes, 6. Mending leaking pipes, 7. Eliminating damp, 8. Introducing moisture barriers like DPMs