Module 03

Question 1

How does the IESNA define an electrical luminaire?

Answer 1

A complete lighting unit that consists of a lamp or lamps together with components designed to distribute the light, to position and protect the lamps and to connect the lamps to the power supply.

Question 2

What does a luminaire provide for a lamp?

Answer 2

1. Physical support
2. Electrical connection
3. Light control

Question 3

To be useful in an architectural application, electrical light sources require external devices to modify their initial distributions. What 2 purposes do they serve?

Answer 3

1. to direct light to where it is wanted
2. to block light from where it is unwanted

Question 4

What is the law of reflection? The angle of _________ equals the angle of reflection.

Answer 4

Incidence

Question 5

What are the three kinds of reflection involved in controlling light? Explain each and give a surface example.

Answer 5

1. Specular – a smooth highly polished surface alters the direction of a beam of light without changing its form (mirror)
2. Semi-Specular – irregular surfaces partially disperse or spread the reflected beam (corrugated, hammered, brushed, sandblasted, etched)
3. Diffuse – rough or matte surfaces neutralize the directional nature of the incident beam. Light is reflected from each point in all directions, with max intensity perpendicular to the surface. (plaster, frosted glass lamp)

Question 6

Specular reflectors contours commonly used in a luminaire include actual or modified ________, _________, and ________ _____. Draw each contour.

Answer 6

Ellipses
Parabolas
Spherical Spheres

Question 7

What is transmission? Draw a diagram of direct, semi-diffused and diffused transmission.

Answer 7

The process by which light passes through a material.

Question 8

What is diffraction? Give an exmaple.

Answer 8

A special type of interference. When a light wave strikes the edge of an opaque substance, its wave properties cause the light pattern to broaden. The visible effect of this is a fuzzy edge to the shadow that is cast by the opaque object.

Ex: A wall sconce with luminaire pointing back at opaque wall that broadens and softens the shadow and edge.

Question 9

What is the principle of concealment?

Answer 9

Is the practice of obscuring high luminance from direct view.

Question 10

Name 2 angles used in relation to concealment. Explain the relationship to a person’s line of sight.

Answer 10

1. Shielding Angle – is measured from the ceiling plane to the line of sight where the bare lamp in a luminaire becomes visible. (higher shielding angles reduce direct glare.)
2. Cutoff angle – is measured from the vertical and indicates the point at which a reflector, louver or other shielding device cuts off direct visibility of a light source.

Question 11

Lighting directly in the field of view needs to be appropriately __________ and/or _________.

Answer 11

positioned
concealed

Question 12

What is a cross baffle used for?

Answer 12

used for small aperture luminaires or along a perimeter system.

Question 13

What type of luminaire will use louvers?

Answer 13

2x4 troffers with fluorescent sources

Point sources

Question 14

What are the 5 types of luminaires?

Answer 14

1. Down lights
2. Wash lights
3. Accent lights
4. Task lights
5. Multidirectional lights

Question 15

What typical mounting types are used in interior locations?

Answer 15

• recessed
  -semi-recessed
  -ceiling mount
  -suspended
  -track
  -wall mount
  -wall recessed
  -cove
  -under cabinet

Question 16

When recessing is not an option, what is the best mounting solution to light from the ceiling?

Answer 16

Surface ceiling mounted

Question 17

What type of mounting is using an electrical raceway?

Answer 17

Track Luminaires

Question 18

What source can be used in small concealed reveals?

Answer 18

LED tape lighting.