C3- Illuminance Levels & Daylight Factor

Question 1

What is a daylight factor?

Answer 1

Something that allows daylight to enter a room.

Question 2

If the daylight factor entering a room is <2%, it is ________.

Answer 2

gloomy

Question 3

How can a daylight factor be achieved in the design of a living room:

The living room can be designed with _____________ so more light travels into the living room.

The _______________ and _________ can be painted in ________________ so internal reflection is achieved.

Answer 3

large windows

internal walls
ceilings
light colours

Question 4

How do you calculate daylight factor?

Answer 4

DF= 100 x illuminance inside/ illuminance outside

Question 5

What are the 3 components of daylight factor?
1.
2.
3.

Answer 5

1. Sky component
2. Externally reflected component.
3. Internally reflected component.

Question 6

What is luminous intensity (cd)?

Answer 6

The power of a light source.

Question 7

What is luminous flux (lm)?
The flow of visible _______________ emitted by a _______________.

Simplified: Luminous flux is a measure of visible light.

Answer 7

light energy
light source

Question 8

What is illuminance (lx)?
The ______________ of __________________ on a surface.

Answer 8

concentration
luminous flux

Question 9

How do you increase illuminance of an object?
1.
2.

Answer 9

1. Decrease the distance between the light source and the object.
2. Increase the intensity of the light source.

Question 10

To increase illuminance of an object, you decrease the distance between the light source and the object.
Why?

Answer 10

Because intensity is inversely proportional to the distance between the light source and object.

Question 11

Glare is the discomfort caused by looking at a high ____________ between ________ and ________.

Answer 11

contrast
light
dark

Question 12

The glare index is studied when designing lighting installations in a building.

What are the 2 types of glare to consider?
1.
2.

Answer 12

1. Disability glare.
2. Discomfort glare.

Question 13

Glare indices ________________ caused by _________ entering a building.

Answer 13

predict the glare
daylight

Question 14

What happens when a retail unit is affected with glare?
Glare can cause __________________ to customers which would make the retail units _____________ to retailers.

Answer 14

physical discomfort
unattractive

Question 15

How does glare affect a retail unit:
1. Glare may cause the retail units to be installed with ________________, so there will be _________________.

2. Glare may make it harder for employees to look at _______________.

Answer 15

window blinds
additional costs

computer screens

Question 16

List 2 daylight factors that vary in a retail store?
1.
2.

Answer 16

1. Internal walls may block daylight.
2. Surrounding built environment may block daylight.

Question 17

Natural light provides good levels of illumination only during what?

Answer 17

Daylight hours in good weather.

Question 18

Natural light reduces the need for artificial light, so it reduces what?

Answer 18

Energy use and energy costs.

Question 19

Why would students work better in a classroom with natural light?

Answer 19

Natural light reduces eye strain so students can focus more.