Venture GlareGuard High Bay Metal Halide

The special lamp pictured here was marketed for a brief period by the American manufacturer Venture Lighting. It was sold under the "Glare Guard" trade name and was originally developed in 1986 together with luminaire firm Qualite, to reduce troublesome spill light in sports lighting installations. Thereafter it was promoted to reduce the glare present in ordinary high bay industrial lighting installations.

The novel feature of this lamp is an internal aluminised reflector on the bulb crown. The size of the aluminised region is chosen such that from ground level, it is not possible to view the arc tube, which normally leads to high glare levels. Furthermore the aluminium layer acts as a secondary reflector which works well with most high bay luminaires. In normal situations, stray light from the arc tube is free to leave the luminaire at any angle and some of the light leaving the arc tube is not controlled by the external reflector at all. With the GlareGuard lamp this stray light is reflected back on to the main external reflector which redirects it into the main beam.

Consequently the beam angle from each luminaire is reduced and it has a sharper cut-off at the edge. At no point from the ground can the arc tube be directly viewed, so glare is considerably reduced. The lamp was marketed primarily to factories where highly detailed work was being carried out to reduce eye strain and fatigue. It is a very sensible innovation indeed and certainly does improve the design of many installations. But presumably owing to the high price and availability from only one manufacturer, it never became popular enough to justify continued production, and it was made obsolete in 1997.
Manufacturer: Advanced Lighting Technologies Inc.
Lamp Power: 400 Watts
Lamp Current: 3.2 Amps
Lamp Voltage: 100 Volts
Cap: E39s/41 (Mogul) Ni Plated + Vitrite
Bulb Finish: Internally aluminise Leaded Borosilicate
Bulb Type: ED-120 ED-37 (in eighths/inch)
Overall Length: 292 mm 111/2 inches
Light Centre Length: 178 mm 7 inches
Electrodes: Backwound coil Thoriated tungsten
Atmosphere: Inner: Ar | Hg (Na,Sc)Ix Outer : Nitrogen
Luminous Flux: 36,000 lm @ 100 hours 23,400 lm mean thro' life
Luminous Efficacy: 90 lm/W @ 100 hours 58.5 lm/W mean thro' life
Colour Temperature & CRI: CCT: 4000K CRI: Ra 65
Chromaticity Co-ordinates: CCx: CCy:
Burning Position: Vertical cap up
Rated Life: 20,000 hours (to 50% survival)
Warm Up / Re-strike Time: 3 minutes 15 minutes max.
Factory: Solon, Ohio, U.S.A.
Date of Manufacture: March 1992
Original / Present Value:
References: 1) Lighting Design & Application, March 1986, p.4