ANSI C78.379-2015 pdf free download

ANSI C78.379-2015 pdf free download.Electric Lamps — Classification of the Beam Patterns of Reflector Lamps.
1 Scope, Purpose, and Application 1.1 SCOPE This standard describes a system for classification of beam patterns and beam angles of reflector lamps. Also a method of describing light output is defined. Reflector lamps are considered to be those lamps having a reflective coating applied to the reflector part of the bulb or a reflector permanently attached to the bulb with the reflector at least partially controlling the light flux distribution. Partial reflector lamps are also covered. Both symmetrical and asymmetrical beams can be classified. Lamps with various kinds of light sources are covered. 1.2 PURPOSE The purpose of this standard is to provide a means to designate nominal beam angles and define expected tolerances about the nominal. This classification applies only to bare lamps and excludes luminaires or other systems. 1.3 APPLICATION The definitions and classification included in this standard apply only to lamps for general lighting applications. 2 Normative References The following publications contain provisions which, through reference in this text, constitute provisions of this American National Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this American National Standard are encouraged to investigate the possibility of applying the most recent editions of the publications indicated below. ANSI C78.21 -2003, Incandescent PAR and R shapes ANSI C78.40-1 992, Specifications for Mercury lamps ANSI C78.42-2004, High pressure Sodium lamps ANSI C78.43-2005, Single-end Metal Halide lamps ANSI C78.380-2005, Method of designation of HID lamps ANSI C78.1 340 – 1 990, 450-Watt, 230-volt self-ballasted Mercury lamps ANSI C78.1 341 – 1 990, 750-Watt, 1 20-volt self-ballasted Mercury lamps ANSI C78.1 342 – 1 990, 1 60-Watt, 1 20-volt self-ballasted Mercury lamps ANSI C78.1 380 – 1 988, 250-Watt, 1 20-volt self-ballasted Mercury lamps ANSI/IES RP-1 6-1 996,
4.2 ASYMMETRICAL BEAM CLASSIFICATION For asymmetrical beam patterns, for example an oval beam, the overall classification shall contain a wide angle sub-classification and a narrow angle sub-classification. Classification angles established using the method of 4.1 shall be employed for each part of a lamp description. In the classification of an asymmetrical pattern, the wide angle sub-classification shall appear first followed by the narrow angle sub-classification. An example of an asymmetrical classification is: 40×20. 4.3 BEAM ANGLE TOLERANCE OF PAR AND R LAMPS Beam angles used in designations are nominal values. However, beam angles of PAR and MR lamps, made from pressed glass lenses and reflectors, vary considerably over time from mold wear.3.3 PEAK INTENSITY (IP) The highest value of light flux intensity in candelas (cd) regardless of whether or not it occurs on the beam axis. See Figure A1 . Note 1 An I p point that falls outside of the beam angle may be ignored. 3.4 BEAM ANGLE (OF SYMMETRICAL BEAMS) The angle, in degrees (º), between the two opposite directions in which the average intensity is 50% of the center beam intensity as measured in at least two rotational planes, 90°from each other, around and through the beam axis. See Figure 1 . The beam angle is the angle between the two defined limitation points with its apex at the face of the lamp. It is not an angle between one limitation point and the axis. 3.5 BEAM ANGLE (OF ASYMMETRICAL BEAM) Those two angles, the largest and the smallest each derived in accordance with 3.4, which lie in the two planes at 90° to each other. See Figure 2. 3.6 NOMINAL BEAM ANGLE A suitable approximate value, declared by the manufacturer, used to designate the beam angle of the lamp. 3.7 BEAM PATTERN The pattern of light displayed on a surface normal to the beam axis. 3.8 FLOOD A generic commercial term that does not by itself define a specific beam angle. Typical use would be for beam angles of 25 degrees or more. The term flood is frequently used with a modifier, e.g. wide flood. 3.9 SPOT A generic commercial term that does not by itself define a specific beam angle. Typical use would be for beam angles no greater than 20 degrees. The term spot is frequently used with a modifier, e.g. narrow spot.