What Does It Mean?

Q: Sunlamps have a series of letters and numbers printed on the ends – for example: “F71-T12-100W BP”. Can you explain what they mean?
Jana McGraw, Solar Dimensions
Kennesaw, GA

Good question, Jana!

A: The letter “F” denotes a lighting industry classification for fluorescent lamps: what we in the tanning industry refer to as low-pressure products. If the lamp is marked “FR71”, it means it’s a reflector lamp. In other words, there is a thin, reflective coating on the lamp’s inside back wall which sends the UV rays in one direction when the lamp is lit. This makes it unnecessary for the equipment to have built-in reflector shields.

The most common designations – “59”, 71”, 72” and “73” – are nominal dimensions, or approximations of the lamp’s actual length. These dimensions were chosen to differentiate tanning lamps from regular, commercial lighting products, and prevent tanning lamps from being misapplied.

For example, the finished lamp specification for a Dominion Plus F71/BP model sunlamp is a maximum length of 70 inches. For the Dominion Plus F73/RDC model, the maximum length is 70.9 inches – that is the maximum length from the end of one termination (bi-pin or Recessed Double Contact) to the end of the other termination. Bi-pin lamps are generally operated on pre-heat ballasts (requiring a separate starter), and RDC styles are generally operated by rapid-start ballasts (starter inside two-lamp ballast). Both lamp styles require two pins at the ends of the lamp; the RDC termination is added when the lamp is designed to be operated on a rapid-start circuit.

The “T” describes the shape of the tubular glass used to make fluorescent lamps. The number following the “T” describes the diameter of the lamp glass in 1/8-inch increments. In this case, “T12” refers to a tubular, glass lamp with a 1.5-inch diameter (12 eights of an inch).

The “W” stands for watts and is a measure of power consumption and heat, not necessarily output. “HO” (high-output) refers to an 80-120W low-pressure sunlamp. “VHO” (very high-output) refers to low-pressure sunlamps, 140-200+ watts.

As mentioned above, “BP” (bi-pin) refers to the two metal prongs extending from the end of the lamp. “RDC” (recessed double contact) refers to the black end caps; the most common lengths are F72 and F73.

The other information and markings printed on the lamp include the country of origin and the “Sunlamp – Danger” warning. The “Hg” marking refers to the lamp’s mercury content.