Lighting & HVAC
Sealing and insulation for parking lot fixtures
By Roberto Naccarato
Outsourcing presents an opportunity for electrical contractors.
By Roberto Naccarato
Parking lot lights must provide adequate outdoor illumination for areas used by both pedestrians and drivers. They are usually pole-mounted and only accessible by bucket truck or lift. Most older parking lot lights use high-intensity discharge (HID) lamps, with ballasts that regulate the voltage supplied to gas-filled capsules. Newer parking lot lights often use LEDs instead. Built with semiconductor chips, these lights last longer, but are more expensive to purchase.
As such, today’s electrical contractors need to know how to install and maintain both types of lighting. While some parking lot owners have their own crews for such work, others outsource it, which provides an opportunity for independent contractors.
And it’s not just new installations and maintenance contracts that can be profitable. LEDs are installed in many retrofits of existing parking lots, even if just a few lights at a time. For electrical contractors, then, it’s important to know what to look for when sourcing the right components.
The surfaces of machined parts might look smooth, but small irregularities can create tiny gaps that admit wind-blown dust and water. With this in mind, the lamps for parking lot lights are housed in enclosures that are designed to prevent the entry of dust and water.
These enclosures may meet specific Ingress Protection (IP) standards, such as IP64, IP65, or IP66. Rubber gaskets—i.e. mechanical seals that fill the space between two or more mating surfaces—help keep out contaminants.
Since they are installed outdoors, parking lot lights are exposed to sunlight and must withstand a range of temperatures, so it is essential to choose gasket materials that will provide the appropriate level of environmental resistance. Otherwise, seal failure could occur and lead to unwanted costs. Parking lot owners do not want to field complaints about lights that do not work, particularly due to avoidable problems like corrosion, and renting a bucket truck or lift to fix a lighting enclosure can be expensive—in some cases, thousands of dollars a day.
Weather-resistant gaskets made of ethylene propylene diene monomer (EPDM) rubber are used for outdoor lighting enclosures. So are silicones with low gassing, since the release of volatile organic compounds (VOCs) can hinder the performance of LED lighting that is hermetically sealed.
Various types of rubber also differ in terms of their durometer, a measure of hardness. To form a long-lasting seal, gaskets need to be just soft enough to support compression but not prevent closure. It is also important to resist ‘compression set,’ the permanent deformation of a gasket.
Liquid caulk can also provide environmental-resistant sealing, but installers may apply it inconsistently or, overall, use too much or too little of it. Pour-in-place gaskets are sometimes used for LED lighting, but this type of sealing is designed for factory installations, rather than field repairs.
Ultimately, rubber gaskets that are cut from sheet or roll materials are easier to install and can accommodate part features, such as angles, notches and holes for fastener heads.
Water-jet cutting is ideal for low- to medium-volume quantities, as there is no tooling to wait for or buy. This equipment’s high-pressure heads direct jets of water toward an x-y axis table with a large cutting surface. This pressurized stream makes fine, fast cuts and minimizes material waste from miscuts, which are a common problem with manual cutting.
Water-jet cutting also supports reverse-engineering projects for hard-to-find or obsolete gaskets. A computer-aided design (CAD) file from a 3-D scan is used to get the process started.
Besides dust, water, sunlight and temperature fluctuations, another environmental issue outdoors is vibration, which can cause noise, loosen fasteners and weaken structures.
When parking lot lights vibrate, it is usually because of the pole’s location. Elevated ramps and parking decks, especially, are problem areas. Light poles that support cameras and other accessories with appendages are also particularly susceptible to wind-induced vibrations.
Fortunately, dampers made of rubber can isolate vibrations. They may be moulded onto metal fasteners.
LED lights generate significant amounts of heat. If this heat is not dissipated properly, the level of illumination may decrease.
Thermal management materials can increase the effectiveness of an integral heat sink, but silicone greases are time-consuming to apply and messy to use. By contrast, water-jet cut gaskets can be installed easily and offer high temperature resistance with low outgassing.
Sealing and insulation techniques for parking lot lighting also differ in terms of bonding.
Hot splicing requires clean, straight cuts and is used for higher-volume quantities. Vulcanization is more forgiving, since the cuts do not have to be smooth and precise.
Cold bonding is a manual process, performed with a brush and an adhesive or glue. It is ideal for low-volume quantities, but cold-bonded gaskets won’t last as long as hot-spliced ones. Moulding, meanwhile, is the only bonding technique that can create rounded corners.
Right for the job
Electrical contractors who install, maintain and repair parking lot lights need to choose the right rubber products for the job. By understanding what to look for in terms of materials and how they are manufactured, they can make their installations easier and longer-lasting.
Roberto Naccarato is sales manager for Elasto Proxy, which fabricates seals, gaskets, and insulation for the outdoor equipment and lighting industries. For more information, visit www.elastoproxy.com.
Editor’s note: This article originally appeared in the October 2019 issue of Electrical Business.