Oracle-lighting OPVDT-22 Instrukcja Użytkownika Pobierz pdf (Strona 2)

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Lighting Solution:

• Select luminaires that minimize intensity in the 55° or 65° to 90°

zone.

• In “vdt normal” spaces with a mix of paper and non-critical

vdt tasks, the ies recommends that the luminous intensity in

the lengthwise, crosswise and 45° vertical planes should not

exceed*:

300 candelas at 65° from vertical

185 candelas at 75° from vertical

60 candelas at 85° or more from vertical

• In “vdt intensive” spaces where the majority of the time is spent

viewing the vdt, the ies recommends that the luminous intensity

in the lengthwise, crosswise, and 45° vertical planes should not

exceed*:

300 candelas at 55° from vertical

220 candelas at 65° from vertical

135 candelas at 75° from vertical

45 candelas at 85° from vertical

• Select luminaires with shielding angles of at least 30° in all direc-

tions.

• Design to a maximum of 50** maintained footcandles on the

horizontal work plane.

• Locate vdt terminals between rows of luminaires when possible.

Other Considerations:

• Windows should be treated with blinds or curtains to eliminateex-

cessive brightness.

• Most vdt terminals may be tilted (up or down) or turned (side to

side) to minimize reected glare.

• White clothing worn by operator may cause some loss of contrast

on screen.

• Negative contrast monitors (dark detail on a light background)

frequently make reected glare less noticeable.

• Monitor design (screen curvature or at screen, screen reec-

tance properties, etc.) can make signicant differences in visual

performance.

• Use of screen lters supplied by manufacturers of visual display

terminals helps to reduce screen glare.

• Partitions may be located as needed to reduce reections from

windows or luminaires. Source: iesna rp-1 (2004) recommended

practice for lighting ofces containing computer visual display

terminals.

*These values are candlepower rather then luminance values as in

previous recommendations.

**Illuminating engineering society of north America (iesna) recom-

mended level.

Louver Iridescence:

• Iridescence Phenomena, present on lighting sheet reectors, is

caused by the refraction of light by the thin anodic coating that

produces either cancellation or reinforcement of certain wave-

lengths of light. This “rainbow effect” appears primarily as various

shades of green and pink that can change color at different view-

ing angles.

• Iridescence has always been present on lighting sheet reectors,

but to a very subtle, often un-noticeable degree with the tradi-

tional uorescent light sources that emitted a broad spectrum of

light. With the introduction of uorescent light sources that utilize

rare-earth phosphors and emit distinct wavelengths of light, the

phenomena of iridescence has been intensied and has become

an aesthetic problem to the user. It should be recognized that the

presence of iridescence does not detract from the optical perfor-

mance of the lighting sheet reector.

• Unfortunately, there is currently no quantitative way to measure

iridescence, so we are left with a purely subjective evaluation

of what is objectionable and this can vary from individual to

individual.

• Low iridescence aluminum is recommended for use with T8,

compact uorescent TT5, and other tri-phosphor lamps.

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RP1

The blades of a parabolic louver provide a physical cut-off

in the same way as in an “egg-crate” louver, however, a

parabolic louver with a specular silver nish reects all

light from its curved blades at an angle equal to or less

than the louver cut-off angle



OPTICAL CUT-OFF ANGLE

LAMP CUT-OFF ANGLE

LOUVER CUT-OFF ANGLE

SHIELDED ZONE

CEILING MOUNT

RP1

IES

T8/T5

OPVDT

1 2 3

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