LIGHTING EFFECTIVELY

This night picture reveals the excellence of the cutoff effect that keeps fhe home; in darkness white pouring light into the park area.

Staff landscape architect for the Skokie Park District was faced with four seemingly opposing problems when planning new lighting for a ten acre park in Skokie, Illinois.

Problem No. 1. The lighting installation must provide security level illumination for the general park area, plus a high intensity level for the general ice skating area.

Problem No. 2. The park is surrounded by homes, immediately adjacent on one side and across streets on the other three sides. In maintaining its good neighbor policy, the District determined that glare had to be at an absolute minimum, and that spill off the site must be eliminated at the property line cut-off.

Problem No. 3. A mounting height had to be developed that would eliminate vandalism and broken fixtures.

Problem No. 4. The Park District maintains its own lighting systems, therefore easy servicing and maintenance was of prime importance.

This day picture shows the attractiveness of the unit as if sours above the surrounding frees.

One of the Park designs using 32 post top poles lost on all counts—mounting height was too low, light sources were visible, breakage (even accidentally) was likely, and installation and operation costs were prohibitive.

A 66 ft. mast featuring a lowerable carriage of four 1,000 watt metallic vapor fixtures provided solutions to all four problems. Its actual strength is designed for 165 MPH winds. It is anchored to the ground by 12 high strength anchor bolts l 1/4" in diameter by 36" long.

It is manufactured of chromemolybdenum tubing, 125,000 PSI and has a 20 to 1 self-sustaining, completely sealed gear box that never needs maintenance. The gear box can be mechanically cranked or electrically operated by the use of a standard electric drill.

The hand hole is 24 x 14 to accommodate a step down transformer and to make it easy to maintain all parts. An extremely thin silhouette, measuring 8 1/2" at the bottom to 4 1/4" at the top, produces a very low overturning moment of 46,400 lbs. resulting in low concrete costs.

The lighting equipment is lowered to the ground by two stainless steel high strength cables (braided aircraft type) each one consisting of 24 strands.

The carriage assembly which houses the lighting equipment is lowered by the cables which have three independent back up systems to guide it. Four nylon rollers at the top assure proper alignment as the carriage is lowered to the base of the pole without injuring the surface paint on the pole.

The electrical system that energizes the head carriage assembly consists of a six core multi-flexible cable with a disconnect the base of the pole. As the lighting equipment comes down, the electrical cable is synchronized to the stainless hoisting cables and goes up to the top. There is also an auxiliary trailing cable which can be installed later to test the equipment while on the ground.

The new lighting system has not interefered

Illinois Parks and Recreation 28 September/October, 1973

with the neighborhood atmosphere and, in fact, has brought praise from the residents. Since the park is surrounded by trees the level of illumination permits silhouetting of nocturnal park users —a feature that assists police in their surveillance of the park from bordering streets.

The lighting system features four 1,000 watt fixtures with 100% of all lumens directed below 90°. The hallast is built into the unit, however a breezeway permits air ventilation, and lessening of heat transfer.

The lamp is stabilized in the luminaire with a stabilization strap to absorb vibrations, shock, and wind oscillation. This protects the filaments of the lamp and also keeps the lamp from backing out of the socket.

The Skokie Park District reports that in just over four years of use the carriage of fixtures has been lowered once (the lamps were shot out). Re-lamping because of use burn-out has not been necessary. The installation has proved to be most satisfactory.

For more information contact: Jack Cooper, Skokie Park District.

GUIDELINE FOR CONTRIBUTORS

Readers are urged to submit copy and pictures as far in advance as possible. Manuscripts should be typed in upper/lower case, double-spaced on one side on 8 1/2" x 11" white bond paper. Black and white glossy photographs should not be less than 4" x 5". Articles of 2-3 pages double spaced are preferred.

Illinois Parks and Recreation 29 September/October, 1973