Manufacturers have rapidly introduced a succession of improved lighting technologies in the past few years, but users have been slow to apply them. New models are announced in rapid order, making product selection confusing and overwhelming. Those users who understand the characteristics and advantages of new products will be able to select models that will produce the greatest cost savings for the investment.

New large screw-base compact fluorescent lamps (CFL) include the following models, which can be used in high-ceiling applications to replace 200-300-watt (W) incandescent lamps. Each model is rated at 65 lumens-per-watt (lm/W).

A new four-pin, rapid-start CFL, rated at 4300 lm (light output equivalent to a 200-W incandescent lamp) is also intended for high-ceiling applications. Electronic ballasts are available, and at least one company offers a matching lamp and ballast system.

T5 Lamps and Ballasts

Cove lighting systems can benefit from T5 lamps and their new ballasts. These 5/8-in. diameter lamps are 12-18% more efficacious than T8 lamps, but they are not intended to replace T8 technology. T5 systems are especially suitable for the higher temperatures found in indirect, confined cove systems (where there is little or no air circulation), because they are designed to produce their peak light output at 35 degrees C (95 degrees F) vs. 25 degrees C (77 degrees F) for T12 and T8 lamps.

New ballast models can power one or two standard T5 lamps of any wattage (14, 21, 28, or 35 W), since all lamps in the standard T5 family operate at the same current (170 milliamps). All models have the same surface brightness, so no matter what length lamp is used to fill out the length of the cove (549, 849, 1149, or 1449 millimeters), cove brightness is uniform.

To increase brightness in coves and for other indirect lighting applications, T5HO lamps are recommended. T5HO lamps have the same physical measurements as the lower wattage, standard T5 lamps, but provide higher light output. T5HO lamps generate up to twice the light output of standard T5 lamps and nearly twice the light output of T8 or T12 systems, which allows half the number of lamps to be used.

The surface brightness of T5HO varies with various power ratings (24, 39, 54, and 80 W). The lamps operate on different currents, so each lamp wattage requires a unique ballast. At 83 to 94 lm/W per watt, they are about 10-15% less efficacious than standard T5 lamps and up to 8% less efficacious than T8 systems.

Both standard T5 and T5HO lamps maintain superior light output over time, only losing 5% of their initial lumen rating in the first 40% of rated life. Both lamp types have excellent color rendering index (CRI) ratings greater than 80.

A new, versatile T5HO ballast, designed to operate two, three, or four F54 (~45-in) lamps has been announced. Multi-lamp versatility, remote mounting, and a high-low switching option make this model attractive for many new applications. Dimming ballasts are also available for T5HO lamps.

Metal Halide

Higher-wattage, pulse-start metal halide lamps support and drive the trend toward white light and, along with ceramic metal halide lamps, are expected to replace incandescent and halogen sources.

Standard metal halide lamps in the 175-1000-W range that make up 70% of existing applications are expected to be replaced by either pulse start lamps or with the expanding family of ceramic metal halide (CMH) lamps.

Low-wattage metal-halide lamps and all high-pressure sodium (HPS) never used starting probes. Instead, they use a proven pulse starter to start the lamps. This starting method is not new--what is new is its use in higher-wattage metal halide lamps.

Standard (probe-start) metal halide lamps use a bi-metal switch inside the lamp to disconnect the starting electrode once the HID lamp is warmed up, which is eliminated in the pulse-start models. The best pulse-start lamp performance results are from a new family of lamps based on formed body arc tubes.

Formed body arc tubes feature higher fill pressures and more uniform geometry than pinched arc seal tubes. Temperature control is improved, which reduces lamp-to-lamp color shift. Design changes result in up to 80% higher lumen maintenance, up to 110 lm/W efficacy, 50% faster warm up and restrike, longer life, and more consistent lamp-to-lamp color.

Ceramic arc tube metal halide lamps, commonly designated CMH or CDM, usually refer to their constant color in their brands. CMH lamps were introduced to eliminate the problem of color shift of standard lamps and use PCA arc tubes--the same material used in HPS lamps. The PCA material reduces the sodium loss that causes color shift.

CMH lamps are commonly available in wattages below 150 W, but 250- and 400-W models are now available. CMH lamps have average rated life of 6000-20,000 hours and their lumen maintenance values fall in the 0.70-0.80 range. Warm (3000 K) or cool (4000 K) color temperatures and improved color rendering (CRI 85 and above) are available.

CMH lamps perform best on electronic ballasts. The advantages of the combination of CMH and electronic ballasts include 10-20% greater light output (which also results in a corresponding higher efficacy) and limited color shift.

Ballasts

A common mistake made is to use instant-start ballasts for switching applications when upgrading fluorescent systems. Lamp life can be shortened for fluorescent systems that are switched with occupancy sensors. The new program-start ballasts designs are recommended instead.

Program-start ballasts extend lamp-operating life and reduce replacement lamp cost. This new ballast design precisely controls the timing of the application of starting and warming cathode voltage to the lamp. Program-start ballasts can outperform rapid-start ballasts by providing from 50,000 to 100,000 starts and an estimated 50% longer lamp life. Buildings commonly have different fluorescent lighting system voltages in various parts of the facility. Many older systems were originally 120-V incandescent that were later converted to fluorescent systems. Later, newer parts of the building often had a 277-V fluorescent system.

New models of electronic ballasts feature universal input voltage that will accept any line voltage between 120-277 V. Input circuitry automatically uses the applied voltage without special taps or switches.

Maintenance personnel can save valuable time when replacing a failed ballast because they don't have to stop and figure out which lighting system voltage applies.

The traditional lighting design for conference rooms has two lighting systems. An incandescent system usually uses recessed cans and is dimmed with wall dimmers. A fixed-light fluorescent system is installed for ambient lighting.

Affordable, line-voltage fluorescent dimming ballasts provide a single system solution. The overhead incandescent system can be removed and the ballasts in the fluorescent system can be replaced with line-voltage dimming ballasts that connect to the existing incandescent wall-box dimmer(s). Lower maintenance cost is the principal benefit.

Test your understanding

1. Instant-start ballasts are recommended where fluorescent systems will be switched.

True or False

2. Which of the following can be used when upgrading standard metal halide HID systems?

A. ceramic metal-halide

B. pulse-start metal-halide

C. both a and b

3. The most important advantage for using T5 lamps is:

A. smaller diameter lamp

B. more light output at higher temperatures

C. new cove lighting

4. Program-start fluorescent ballasts feature longer lamp life.

True or False

5. The main cost savings for fluorescent ballasts with universal voltage feature comes from:

A. inventory reduction by cutting the number of replacement models

B. lighting audits when fluorescent fixtures do not need to be opened

C. exorbitant distributor restocking charges

Answers

1. false

2. both a and b

3. b

4. true

5. a