High-mast LED

The typical existing inventory of high mast fixtures is made up of either high pressure sodium fixtures or legacy MH fixtures. This project will evaluate the energy efficiency and demand reduction potential of retrofitting the high masts with the new generation LED fixtures. To accomplish this the existing fixtures will be monitored, and baseline data will be collected for at least 2 weeks. After the retrofit post installation monitoring will be conducted for another 2 weeks at the minimum. Before and after power readings will be compared to calculate the average energy savings and demand reduction. In addition, the light level readings will help evaluate the illuminance performance of the new fixtures compared to the incumbent/baseline fixtures.

This evaluation aims to study and evaluate the potential of Light Emitting Diode (LED) lighting as an energy efficient alternative to traditional High Pressure Sodium (HPS) lighting in high mast applications, and to determine if LEDs can perform and provide required illumination, while providing energy savings, improved maintenance, and cost savings. To achieve the objectives of this evaluation, a test site was selected in Long Beach, California The test site is a marine terminal that includes shipping container transport facility and is currently illuminated with high mast poles consisting of an array of 12 1,000 Watt (W) HPS luminaires (1,080 W connected load with ballasts) per pole. Two adjacent masts located at the test site were utilized to compare electrical and illumination performance of existing HPS fixtures to the 2nd generation LED lighting. One high mast pole with twelve 1,000 W HPS luminaires was re-lamped and monitored for a period of at least 15 days to determine baseline power consumption. HPS illumination levels were determined by a site survey that recorded footcandles (FC’s) within the illumination zone of a single high mast pole. The adjacent high mast pole was retrofitted with twelve 500 W LED high mast luminaires. These LED luminaires replaced 12 existing 1,000 W HPS luminaires (1,080 W connected load with ballasts). The LED fixtures were also monitored for 15 days to determine its power consumption. In addition, the LED illumination level was also determined by a site survey that recorded FC’s within the illumination zone of this single high mast pole with 12 LED luminaires. AGI-32 lighting design software was used to create HPS and LED lighting models that mirrored the test site. AGI-32 models replicated site conditions and projected lumen maintenance and long term performance. Models provided: -Expected illumination for incumbent HPS at initial installation and as projected to useful “maintained” illumination (80% of lamp life). -Expected illumination for LED lighting at initial installation and as projected to useful “maintained” illumination (IES LM70). The test site follows OSHA requirements for marine terminals and Cal/OSHA requirements for general industry. For work areas that are not considered “active work areas” the minimum illumination requirement per Federal Occupational Safety and Health Administration (OSHA) is 1 FC and when unoccupied, the minimum FC requirements for these areas is ½ FC for security. Similarly in California Occupational Safety and Health Administration (Cal/OSHA) the minimum illumination level for loading areas and corridors is 1 FC and for storage yards it is ½ FC. In actual practice, the test site targets 2 FC illumination from the high mast system. Higher FC requirements of OSHA and Cal/OSHA for work spaces during loading and unloading can be met by task luminaires mounted to cranes and platforms within the marine terminal’s storage yards. The illumination target for active storage areas and general construction areas that require low lighting set by OSHA and Cal/OSHA respectively is 3 FCs. Cal/OSHA’s requirement for active storage areas is 5 FCs. The average FC’s measured at the test site was 2.24 FC for the single pole LED versus 4.69 FC for single pole HPS. Although the LEDs measured FC’s were below those of the HPS light levels they were still well above the minimum 1 FC OSHA and Cal /OSHA requirement for work areas and corridors & inspection respectively. LEDs were also able to meet the ½ FC requirement for safety/security for marine terminals by OSHA and for storage yards by Cal/OSHA AGI-32 modeling of a 20-pole LED array storage yard that mirrored a portion of the test site produced an average 4.5 FCs, which is well above the OSHA’s 1 FC requirement at the test site as well as the 3 FC requirement for active storage areas and general construction areas. AGI-32 modeling and site survey, with illumination measurements, determined that the LEDs delivered higher quality of light and better light distribution in comparison to HPS lighting. In addition, if Illumination Engineering Society TM12 and TM24 recommendations are considered, which base their optional design practice on the Scotopic to Photopic Lumens (S/P) ratios of the selected light source, single pole LED lighting also has the ability to meet higher illumination requirement of 3.0 FCs. Uniformity results of the two sources indicate that LEDs exhibit excellent uniformity. The uniformity of LED lighting was 6:1 while that of the HPS lighting was 16:1. The LED array is almost three times more uniform than the HPS array at the test site. LED in high mast applications can provide an improved quality of illumination compared to traditional HPS lighting while meeting the OSHA and Cal/OSHA minimum FC requirements of the test site. Because of improved light uniformity and the LEDs higher S/P ratio, visual acuity of the illuminated areas is also improved.