New Year, New Standards: T8 Rules

New T8 standards

In 2015, the U.S. Department of Energy (DOE) issued new energy standards for general-service fluorescent lamps. These standards identify lamp categories and impose minimum efficacies expressed in lumens per watt. Primarily affecting 4-foot, 32-watt (W) T8 lamps and some reduced-wattage T8 lamps, the new standards are set to take effect Jan. 26.

The Energy Policy Act of 1992 regulated general-service fluorescent lamps and granted the DOE rule-making authority. In 2009, the DOE expanded coverage to include 8-foot T8 and 4-foot T5 lamps as well as a broader range of wattages of 4-foot T8 and T12 lamps. Effective July 2012, these rules eliminated a majority of T12 lamps. Lower color rendering (700 series) 4-foot T8 lamps also did not comply, but the DOE granted a two-year exemption to manufacturers that requested it.

The 2015 rules tightened existing energy standards for 4-foot linear T8, 2-foot U-bend T8, 4-foot linear T5, and 4-foot linear T5HO lamps. Minimum required efficacy for T8 lamps increased 1 to 4 percent, up to the maximum technology level. Minimum required efficacy for T5 lamps increased 7 to 10-plus percent. Eight-foot lamps saw no increase. The DOE extended the range of covered wattages for 8-foot single-pin lamps and 4-foot T5 and T5HO lamps.

Existing exemptions will continue to apply, including lamps designed to promote plant growth, lamps designed specifically for cold-temperature applications, colored lamps, impact-resistant lamps, reflectorized or aperture lamps, lamps designed for reprographic applications, UV lamps and lamps with a color rendering index of 87 or higher.

The regulations provided a three-year window for manufacturers to evaluate their products and discontinue or re-engineer them. Eliminations are expected, which may affect lamp availability and cost, though popular models may still be available. After Jan. 26, distributors may continue to sell lamps manufactured or imported before that date until inventories are exhausted.

4-foot linear T8 lamps: At the time of regulation, a majority of these lamps passed the new standards. These were primarily 25W, 28W and 30W lamps. However, basic-grade 32W T8 lamps did not comply and would need to be redesigned or discontinued. Similarly, 32W lamps had to be designed to offer extended life. Lamps with lower color temperatures were disproportionately affected.

If the installation uses continuous-dimming ballasts, the end-user will have to determine whether the ballasts are rated for reduced-wattage lamps. Operating reduced-wattage lamps on incompatible dimming ballasts will produce unsatisfactory performance. If the ballasts are not rated for reduced-wattage lamps, the end-user must replace the lamps with compliant full-wattage lamps or replace the dimming ballast with a ballast rated for reduced-wattage lamps.

Two-foot U-bend T8 lamps: As with 4-foot linear T8 lamps, a majority initially complied with the new standards; however, again, these are low-wattage models. Many 32W models did not comply and would be discontinued or re-engineered. It is expected that popular 32W models will continue to be available.

A substitution issue centers on whether the lamp has 15/8-inch or 6-inch leg spacing. A majority of users of 6-inch leg spacing use full-wattage lamps on control systems so they can be dimmed, while users of lamps with 15/8-inch spacing use reduced-wattage lamps.

4-foot T5 and T5HO lamps: A majority of 4-foot T5 and T5HO lamps comply. At the time the regulations were announced, major manufacturers expected their existing product lines would satisfy the energy standards with limited re-engineering, resulting in a minimal impact on availability.

In 2010, the DOE estimated that 20 percent of all commercial building sector lamps and 44 percent of industrial sector lamps were 4-foot T8, representing some 532 million 4-foot linear T8 lamps and 14 million T8 U-bend lamps. In its justification for the new standards, the DOE estimated, over the next 30 years, end-users would receive an average payback of 3–4 years and cost savings with a cumulative new present value (factoring energy cost savings and higher purchase cost) of $2–5 billion based on a respective discount rate of 7 and 3.3 percent.

Energy savings are only gained, however, if the end-user switches from a full-wattage T8 to a reduced-wattage T8 lamp or operates a compliant full-wattage T8 lamp on dimming controls. Alternatively, they may make the switch to LED to achieve higher energy savings and potentially increased capabilities. Options include LED replacement lamps, retrofit kits and new luminaires.

Overall, the 2015 rules represent another step in removing the least-efficient and lowest-cost lamps from the market. Electrical contractors may benefit from consulting with lamp manufacturers about availability and then advising their customers about the impact on their lighting systems.

End-users should consider the benefits of a comprehensive upgrade rather than replacing noncompliant lamps individually as part of maintenance. A comprehensive upgrade can ensure lighting quality is maintained or improved, reduce the risk of matching incompatible components, and consider all options, such as LED and advanced controls.

Contact the lamp manufacturers for more information.

About the Author

Craig DiLouie

Lighting Columnist
Craig DiLouie, L.C., is a journalist and educator specializing in the lighting industry. Learn more at ZINGinc.com and LightNOWblog.com .​

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