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St Josephs Cathedral - Custom QL Induction Retrofit

St Josephs Cathedral – Custom QL Induction Retrofit

New Haven, CT – Grand Light successfully designed and tested a custom QL induction lighting system retrofit kit for 232 historic luminaires at the St Joseph’s Cathedral in Hartford, CT.

Exterior of Saint Joseph’s Cathedral, Hartford, CT Sanctuary illuminated by original fixtures

The original luminaires, manufactured by Frink Electric have a complex reflector and lens system to direct high-intensity incandescent light to the pews 100 feet below. Calculations revealed that system likely provided about 28 foot-candles (fc) of average illumination on the pews with 1000W incandescent lamps. It also used an extraordinary amount of energy, 216,000 watts or about 11.7 watts per square foot (w/sf).

Luminaire Cluster Lower Reflector System Upper Fresnel Lens System

Prior to the retrofit installation, these luminaires were lamped with 500W incandescent systems, with the measured light levels in the range of 3.0 to 8.0 fc. This type of lamp saved half the energy, however it was providing only about 25% of the original light levels, significantly below Sanctuary lighting recommended levels of 10-20 fc, and power density to meet current energy standards.

Induction lamp technology seemed appropriate for this high-ceiling application. It has an extremely long rated lamp life of 100,000 hours, very good color rendering characteristics, exceptional lumen/watt efficacy, instant hot/cold re(start), and stepless dimming capability.

For reasons of historic preservation and to maintain the visual quality provided by the original luminaires, an independent study recommended that the Archdiocese authorize Grandlight to evaluate the necessary engineering, photometric modeling, and testing for a 165W induction system retrofit.

After considerable testing of various mock-ups, the Grandlight Design Team developed a retrofit concept which met the client’s criteria of a simple plug-in installation, increased illumination levels, improved light distribution, easy maintenance, and the overall fixture design to qualify for the QL Lighting System 10 Year Extended Warranty.

Assembly Drawing
Retrofit System
Retrofit System/Luminaire

The existing 232 historic luminaires were retrofitted with a 165W induction lamp, positioned properly in the lens and reflector assembly, in order to provide a lighting quality more similar to the original system. Due to the design of the retrofit kit housing, the average light level exceeds 17.0 fc while only using 1.9 w/sf of power.

Ceiling view of the light clusters shows the difference between the old(left) and the new(right) systems Completed Luminaire
Reflected floor view Illumination example

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