Fixture Size

Line-voltage lamps operate with a much higher voltage, consume a much higher wattage, and are typically much larger than the low-voltage alternative. To house the larger line voltage lamps, the physical fixtures tend to be larger.  These larger fixtures are much more challenging to blend into the landscape. In comparison, the fixtures that house the smaller low-voltage lamps are also smaller and less obtrusive.

When selecting exterior fixtures, consider manufacturers that design low profile products.  These landscape lighting products will provide the desired outdoor light discreetly. 

Potential Electrical Shock

Any electrical system expected to work outdoors must be designed to deal with the elements. Lighting is certainly no exception.

While both low-voltage and line-voltage systems are designed to be safe outdoors, the danger represented by a low voltage shock is dramatically different from a line voltage shock. A transformer steps down the voltage being delivered to the low-voltage system. Once this occurs, approximately one-tenth of the original line voltage remains to flow through the wiring and the lamps. This significantly reduces the shock hazard. Shocks received from exposure to line voltage are very dangerous and potentially fatal.

 

 

Goal: Material Efficiency 

Energy efficiency is not the only area of interest for teams trying to improve the sustainability of landscape lighting designs. It is also important to select products that are material efficient. The focus of material efficiency is the physical product, the life of the product, the impact that the product has on the environment from cradle to grave and necessary maintenance.  When designing exterior lighting systems, selecting fixture materials that have zero or low toxicity, are highly recyclable, durable and built to last are all important aspects of employing products that are material efficient.

Select Metal Fixtures 

Metal fixtures are often best equipped for meeting the watertight and heat management demands of exterior lighting. Photo courtesy B-K Lighting

Lighting fixtures destined for the outdoors must be designed to accomplish two objectives. First, moisture must be kept out of the area housing the socket and the lamp. If the socket becomes wet, the fixture will short out. Second, the heat created by the lamp when it is illuminated must be managed. If too much heat builds up around the lamp, the lamp will overheat and fail prematurely. 

The pursuit of this watertight and, simultaneously, cool environment is challenging because in order to keep dew, rain, snow, and other condensation away from the socket, the area must be airtight.  In an airtight setting, neither moisture, nor air, nor heat can pass freely from the source to the exterior. Instead, the physical fixture becomes responsible for dissipating the heat.

The need to manage heat is the reason that high-quality outdoor fixtures are made of metal. It is also the reason that plastic fixtures are usually short-lived. Brass and aluminum effectively absorb the heat created by the light source, acting similar to a heat sink. The heat transfers from the lamp housing to the metal fixture and then radiates from the fixture into the environment.

Beyond functionality, another benefit of using brass and aluminum in the body of the fixture is that both metals are renewable and recyclable. Brass is the combination of copper and zinc and, today, almost 90 percent of all brass alloys are recycled. Aluminum is the most abundant metal in the Earth's crust, and the third most abundant element overall, following oxygen and silicon. Soda cans, scrap metal, lighting fixtures and all other things aluminum can be recycled.

Improve Fixture Durability: Conversion Coating + Powder Coat

The durability and longevity of exterior lighting products are important aspects of their sustainability.  If the products have a short lifespan, they will create more trash year after year than will a product that stands the test of time. If the product still works, but is an eyesore, it is not considered functional by sustainable standards either.

Metal is an excellent material to use for exterior lighting, because of its ability to absorb heat and be recycled. However, many metals, including aluminum, naturally corrode when they are exposed to water and oxygen. Corrosion weakens the metal, first forming a pit or crack in the surface, which then spreads, causing deterioration and the eventual failure of the product. In order for metal lighting fixtures to provide reliable performance in the wind, snow, rain, heat, humidity and salt spray, the aluminum must be protected against the elements.

It should be noted that when aluminum is exposed to moisture or air, it naturally forms an aluminum oxide layer on the surface of the metal.  Unfortunately, this oxidized layer is non-uniform, provides poor corrosion protection, and creates a surface on the fixture that is difficult to paint. 

Luckily, aluminum products and components can be protected against corrosion by being sealed inside and out with a pretreatment process called conversion coating and then finished with a dry coat of paint called a powder coat.  The conversion coating changes the surface of the metal to be more corrosion-resistant and to better grip the protective powder coating that will be applied to the metal after the conversion treatment has been completed.

The key to longevity for outdoor fixtures is to begin with a quality metal, such as copper-free aluminum. Then pre-treat the metal with a conversion coating to create a clean and corrosion-resistant surface and apply a tough powder coating that will protect the fixture from chipping, fading, cracking, or becoming otherwise defective. This combination treatment of conversion coating and powder coating significantly improves the durability and lifespan of the exterior lighting fixture in even the harshest atmospheric conditions.

Aluminum components can undergo a conversion coating by either being dipped into a solution or sprayed.  When dipped, the conversion coating not only bonds to the metal surface, but wraps around the entire product creating an extra protective layer. With a dipped conversion coating, even if the surface paint is compromised, the aluminum will not deteriorate.

A conversion coating that is sprayed onto the surface of the aluminum creates a protective coat that is thinner and more easily penetrated.  The spraying process also has a greater potential for creating a less uniform coating, which, subsequently, impacts its effectiveness in the field.