The architecture of light: architectural lighting design concepts and techniques. A textbook of procedures and practices for the architect, interior designer and lighting designer pdfdrive com

LAMP NAMING LOGIC
One of the more helpful elements of lamp technology comes in understanding the naming convention that is used to describe the shape and sizes of common electric lamps.
Most lamps are given a description code of 2 or 3 letters followed by 2 or
3 numbers. In most cases, the letters are some manner of describing the lamp shape, and the numbers are a manner of describing the size.
Figure 8.11 Most lamp names describe the lamp diameter in 1/8” increments.
Lamp Size
The sizing of lamps is very simple, if not utterly logical. Common electric lamps sizes are indicated by a two-number code that describes their size in ⅛” increments. By this logic, our common light bulb, which in lighting circles is referred to as an A-19 lamp, is ” in diameter or 2-⅜” in diameter. This measurement turns out to be accurate as we go down the line from small lamps like MR-16 lamps ( ” or 2” in diameter), to larger PAR-38 lamps ( ” or 4-
¾” in diameter). Figures 8.11 and 8.12 illustrate a few examples of these size
codes.
Lamp Shape
The system for describing the shape as a code is a little more varied. Inevitably, the two or three letters leading a lamp code are meant to give some literal indication of the shape of the lamp. A stroll through the family illustrates some examples.
A-lamps, which include the A-19 (common light bulb), A-21, and A-23,
are named such that “A” stands for “arbitrary.” This is presumably due to its irregular shape.
Next in the lineage of directionality are so-called “R” lamps, like R-20, R-
30, and R-40. In all of these cases, R stands for “reflector,” presumably to describe the generic silver backing common of these lamps.
Figure 8.12 Common sizes of the arbitrary shaped “A” lamp (left) and reflector “R” lamps (right).
We then encounter our PAR lamps, like our PAR-20, PAR-30, and PAR-
38. PAR stands for Parabolic Aluminized Reflector and refers to the engineered parabolic reflecting surface built into each of these lamps.
Figure 8.14 Common sizes of parabolic aluminized reflector “PAR” lamps.
When we discuss MR lamps, like the ubiquitous MR-16 and the smaller MR-11 and MR-8, the MR stands for Multifaceted Reflector; a very highly- engineered reflecting device.
Figure 8.15 Common sizes of multifaceted reflector ‘’ MR” lamps.
T-lamps tend to be “tubular” in shape, as is the case with our linear fluorescent T-8 and T-5 lamps. T-lamps can refer to smaller, tubular halogen or HID lamps as well.
Figure 8.16 Common sizes of tubular (T) lamps.
The parade of names and codes goes on, but the lamps mentioned above represent most of what we run into in the world of architectural lighting.