Leif Zars

Tests were made utilizing one or two 500 watt swimming pool lights submerged 30" underwater in two distinctly different pools - one with normal white plaster and the other with a "dark" green plaster.

Test readings were taken in candelas/meter2 at various distances from the light source. These readings were taken of the light values as would be seen by a person standing along he edge of the pool.

The attached 4 drawings indicate the light levels in cd/m2 obtained under the described conditions. Using the recommended figure of 0. 5 Candelas/rn2 derived in the NSPF/UT Lighting Study the following observations are made.

Conclusions: A 500 watt swimming pool underwater light provided adequate lighting in cd/m2 (0.5) up to a distance of 30' away, or roughly up to 1600 f2 of pool surface area in a semicircular pool down to a low of say a 15 ft wide pool 30 ft in length or 450 f2. In the dark colored pool this distance is reduced by approximately one half that amount. The NSPF/UT study made recommendations regarding white finished pools only.

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