What is Light Pollution?

What is Static Pressure Static pressure is a measure of the resistance against airflow as the fan pushes air through a duct. It is measured in inches of water column or water gauge, such as 0.25" w.g. to show that resistance is equal to a column of water gauge. It is expressed as 0.1" w.g. or 0.25" w.g. to show that the resistance is equal to a column of water one-tenth or one-quarter of an inch tall.

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What are the measurements of the oversized wall plates?   Oversized wallplates are 0.75 inches higher and wider than standard wallplates. They are used to conceal greater wall irregularities than those hidden by the extra coverage provided by Midway wallplates. All 1-Gang Oversized wallplates are 5.25" H x 3.5" W. Add 1.8125" for each additional gang.

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A unit of wavelength equal to one billionth of a meter

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A high intensity discharge light source in which the light is produced by the radiation from mercury, plus halides of metals such as sodium, scandium, indium and dysprosium. Some lamp types may also utilize phosphor coatings.

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A measure of the luminous flux or quantity of light emitted by a source. For example, a dinner candle provides about 12 lumens. A 60-watt Soft White incandescent lamp provides about 840 lumens.

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