Osram HNW72 16W U-shaped Fluorescent

This is believed to be one of the earliest U-shaped fluorescent lamps, having been made in 1950. The original inventor of the U-shaped lamp is not known, but in view of their popularity in Germany as well as the extensive product ranges offered by the German lampmakers Osram and Narva, it is suspected that the design may have originated there. Although Osram exhibited its first fluorescent lamps in 1936 (for neon sign illumination), the production of general lighting lamps did not happen until 1940, in very small quantities for the illumination of subterranean war factories. Osram's lampmaking activities were practically destroyed during the war, and key Eastern factories lost to the Soviet invaders which were amalgamated to form the Narva group. It was not until 22nd January 1946 that linear fluorescent production could restart, at Factory-S in Berlin. The first U-shaped lamps were produced there on 15th August 1949.

The nomenclature of early Osram fluorescent lamps is often difficult to understand, especially this type HNW-72 S. The first letter H refers to a Mercury discharge lamp. N=Niederdruck, i.e. Low Pressure. The third letter indicates the light colour where I = Incandescent, W = Weiß (white) H = Hellweiß (bright white), and T = Tageslicht (daylight). A suffix -Z is added in case of "Zweischicht" or double-coated lamps, having a second phosphor coating to improve the colour rendering quality. The number indicates the lamp model, the first digit indicating the main type and the second the variant. In this case, 7 is used for the 16W rating and 2 refers to the second variant, in this case meaning the U-shaped variety. The last letter S in a square box refers to the type of ballast. Each German ballast used to have its own unique letter identifier.
Manufacturer: Osram Kommanditgesellschaft
Lamp Power: 16 Watts
Lamp Current: 0.2 Amps
Lamp Voltage:
Cap Type: 2x G13 Nickel Plated Brass + Plastic
Bulb Type: TU-26 TU-8 in eighths/inch
Bulb Finish: HNW White Lead-alkali glass
Electrodes: Triple Coil Tungsten BaCaSrCO3 emitter
Arc Length:
Atmosphere: Hg | Ar
Luminous Flux: 800 lm (@ 100hrs)
Luminous Efficacy: 50.0 lm/W (@ 100hrs)
Colour Temperature & CRI: CCT: 4000K CRI: Ra 70
Chromaticity Co-ordinates: CCx: 0.380 CCy: 0.380
Rated Lifetime: Not published
Warm-up & Re-strike time: 1 minute Instant
Burning Position: Universal
Dimensions: 370 x 82 mm 141/2 x 31/4 inches
Light Centre Length: N/A
Factory: Werk-S, Helmholzstraße Berlin, Germany
Date of Manufacture: 1950 Date Code: z32
Original / Present Value: DM 8.55 (c. 1959) GB £6.5 (2015)
References: 1) Osram Catalogue, Germany, c. 1959.
2) Siemens-Schukert Osram Catalogue, Germany, September 1960.
3) Osram 1945-1955 10 Jahre Wiederaufbau und Ausbau, Sonderausgabe Osram-Nachrichten Werkzeitschrift, Juni 1955, pp.13 & 16.
4) 100 Years of Osram, Centenary Book 2006, p.38.