F luorescent and compact fluorescent lamping have been the standard in commercial lighting for decades. Safe, extremely reliable, affordable, and offering many aesthetically pleasing options, these lamps remain an excellent choice for many applications.

Lamping codes: FA, FD, FA/U, FD/U, -D
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Crenshaw Standards

Crenshaw most frequently uses triple tube (TBX) PL-T compact fluorescent lamps where an omni-directional effect is desired, and long twin tube (BX) PL-L lamps where a more linear omni-directional effect is desired, in fixtures up to about 40″ in length. For fixtures longer than 40″ or where other issues such as heat are a factor, tubular twin socket bi-pin fluorescents are sometimes used. Ballast availability for particular lamps can also be a factor in lamp selection. Integral ballasts typical, Universal Triad non-dimming and Advance Mark X dimming typical.


Crenshaw Historic Bowl Pendant 3726-PBC2
Historic City Beautiful style bowl pendant designed for the Supreme Court of the United States Modernization Project, 2006. (8) 42W + (4) 18W QBX PL-T compact fluorescents provide energy-efficient high performance uplighting and aesthetically pleasing bowl illumination.

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Compact Fluorescent Biax (PL-L) & TBX (PL-T, PL-C) Lamps

Exact specs vary per manufacturer. Color temperature and CRI are usually indicated where noted by xxx. For example, 830 indicates 80 CRI @ 3000K. 741 indicates 70 CRI @ 4100K.


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Fluorescent Linear Twin-Socket Bi-pin Lamps

Exact specs vary per manufacturer. Color temperature and CRI are usually indicated where noted by xxx. For example, 830 indicates 80 CRI @ 3000K. 741 indicates 70 CRI @ 4100K.

    View Wattages, Lumens & Sizes


The Upsides

  • efficient (60-85 lumens per watt, on average) equates to lower energy costs over time
  • reliable, proven technology
  • safe (electrical, heat)
  • modest upfront lamp costs
  • relatively easy lamp replacement
  • superior lamp performance, color rendering, and efficiency options available when compared to CFL replacement lamping (such as twister screwbase styles)
  • longer lamp life (16,000-20,000 hr avg)
  • modest upfront fixture costs except where high output sophisticated dimming is required
  • with good fixture design, appropriate lens materials, and high CRI, warmer color temperature lamps, beautiful aesthetic results are achievable
  • many sophisticated controls are available
  • Crenshaw’s standard cf dimming option (Advance Mark X) is designed for 2-wire electrical systems and may be easily retrofitted into a building wired for incandescent
  • emergency battery packs are available in a variety of options for many fluorescent ballasts
  • UL general coverage classification applies to all-fluorescent fixtures (not applicable for mixed lamping), due to safety and reliability factors. This eliminates UL/CSA listing fees and shortens lead times. (*Not applicable for wet location fixtures.)

The Downsides

  • for some, aesthetic features are less than ideal, including inferior light quality when low-quality lamps with poor color rendering values are used
  • because so many lamp options are available for a given lamp specification, controlling light quality on a project long term can pose a challenge, particularly related to lamp selection for color temperature and color rendering
  • not appropriate for some traditional fixture designs
  • ballasts must be replaced periodically, as well as lamps, adding maintenance costs over time
  • diagnosing system failures is more intensive than with traditional incandescents – while deductive reasoning can be used to evaluate ballast and lamp failure based on projected life expectancies, ultimate certainty cannot be had, particularly with ballasts, without actually replacing them, unlike incandescent lamps which can be quickly evaluated on sight
  • lamps dim somewhat at the end of their life cycle
  • lamps must warm up to full brightness even with instant-on ballasts (this is less pronounced than with CFL replacement lamps such as twister style lamps)
  • toxicity issues related to mercury vapor, special clean-up procedures required for breakage, hazardous waste disposal issues. Read EPA’s guidelines.
  • space and heat limitations for some fixture designs (ceiling fixtures, ADA sconces, low-profile fixtures with minimal metalwork) with integral ballasts, particularly dimming ballasts
  • sophisticated high output dimming fixtures can pose significant upfront fixture costs, sometimes close to the cost for board and driver LED fixtures
  • not ideally suited for clear frosted lenses