By Michael Arny
Why should you implement a high-efficiency, low-mercury light bulb purchasing plan?
Replacing incandescent light bulbs with energy-efficient fluorescent bulbs is a great way to reduce the energy use of a building. More efficient lighting means less coal and other fuels are burned to produce the same amount of light, resulting in lower emissions of mercury and greenhouse gases. Besides being energy efficient, fluorescent bulbs are good for the environment because they have a 10 to 20 percent longer life than incandescent bulbs. This means they provide the same amount of light with fewer resources used and potentially less going into landfills. However, fluorescent bulbs require a small of amount of mercury for them to function. The use of fluorescent bulbs must be carried out in such a way as to minimize release of mercury into the environment, which can affect human health. Exposure to mercury can result in deleterious effects on the brain and nervous system, particularly in infants and young children.
There are two aspects to the environmentally safe use of fluorescent bulbs. The first is to use fluorescent bulbs that produce the most light over their lifetimes relative to the amount of mercury contained in the bulbs. In recent years bulb manufacturers have significantly reduced the amount of mercury in their bulbs. The second is to recycle fluorescent bulbs. Almost all parts of fluorescent bulbs can be recycled, including the mercury. More effort needs to be made in this area, because currently only about 24 percent of fluorescent bulbs are recycled. The rest end up in landfills, where many are broken and about half of the mercury content is released to the atmosphere. A combination of using the bulbs with the lowest mercury relative to light output and recycling those bulbs will enable the most environmentally friendly use of energy efficient fluorescent bulbs.
How can you reduce your mercury footprint and help drive down the amount of mercury in high-efficiency light bulbs?
Use your purchasing power!
1) Develop a low-mercury, high-efficiency light bulb purchasing plan for your building.
2) Track and maintain the plan.
3) Establish a process for continuous improvement of the plan.
Developing a low-mercury light bulb plan for your building is based on the “picogram mercury per lumen hour index”. This number shows how much mercury is in a particular bulb in relation to the amount of light the bulb produces over its life. This number is specific for each manufacturer and model number. The aim is to use bulbs with the lowest index possible. A lower mercury content, a higher light output, and a longer bulb life all contribute to a lower-mercury index for a bulb.
The measure of mercury in all the bulbs in a building and on site is the “weighted average picograms mercury per lumen hour”. The weighted average is the total of all the mercury in bulbs in relation to the total amount of light provided by these bulbs over their lives and the total length of life of all the bulbs. The amount of mercury in a bulb has a lower contribution to the weighted average if fewer bulbs of that type are present, if more light is produced by the bulb or if the bulb has a longer life. As with the index, the aim is the lowest weighted average possible.
What are the steps for developing a low-mercury, high efficiency light bulb purchasing plan for your building?
Step 1: Where are you now?
To determine the bulb mercury currently in your building and on site, inventory the mercury-containing bulbs present. For each bulb in use, record the manufacturer and model number. Collect the following data for each bulb: the milligrams of mercury in one bulb, the average lumens, and the average life in hours. Some of this data is available online on manufacturer websites. Other data must be requested from the manufacturer. Our suggestion is that you ask your bulb supplier to obtain the information for you. Once the data is obtained, calculate the “weighted average picograms mercury per lumen hour” for your building and site. Several calculators are available online to assist with this calculation. Leonardo Academy has one on its website (www.leonardoacademy.org, search “mercury calculator”). The data for bulbs from any manufacturer can be entered into the calculator to determine the building/site weighted average mercury or the mercury index for a particular bulb model. (Note: All manufacturers are invited to submit their light bulb data to Leonardo Academy to add to this calculator.)Step 2: Evaluation.
Does this weighted average mercury meet your goals?Step 3: Going forward.
To decrease the weighted average mercury for your building, wherever possible, identify the manufacturer and model numbers of higher-efficiency, lower-mercury bulbs to replace the bulbs you are using. Create a “projected inventory” of bulbs incorporating these replacements. Calculate the weighted average mercury per lumen hour for this “projected inventory”. Compare the weighted averages for the current and projected inventories. If the projected inventory weighted average is lower, you have the basis for an improvement plan. The list of manufacturer and model numbers in your projected inventory is your low-mercury purchase plan for mercury containing light bulbs.Step 4: Implementing your low mercury purchase plan.
Create a policy that only bulbs from the purchase plan will be purchased. As replacement bulbs are needed, purchase bulbs from the plan. Over time, all the mercury containing bulbs in your building will be “plan” bulbs, and you will have decreased the weighted average mercury to the plan value.Step 5: Tracking and maintaining your purchase plan.
Confirm that your low-mercury purchase plan is being followed by checking bulb purchases against your low-mercury purchase plan.Step 6: Improving your purchase plan.
As lower-mercury bulb alternatives become available, update your purchase plan to include these bulbs. Recalculate your weighted average mercury to document your improvement.
How much does it cost for a company to decrease the weighted average mercury in its building?
Most companies report that low or no cost is involved. The low-mercury light bulbs are similar in price to the higher-mercury bulbs being replaced. Make the replacements of high-mercury bulbs with low-mercury bulbs over time, as replacements are needed anyway. Accomplishment of this goal is mostly a matter of paying attention to what is purchased.
What levels of mercury can be attained?
The level required by LEED-EB v2 and LEED-EB O&M are 90 picograms per lumen-hour for 1 point and 70 for 2 points. For LEED-EB O&M 2009, 1 point is available for 90 picograms or below. For all these rating systems, an additional point is available for additional mercury reduction. Much lower weighted averages of mercury can be attained. Johnson Diversity Inc., for example, reached the very low level of 18 picograms mercury per lumen-hour for their distribution center building that they lease from Liberty Property.
Remember! A low mercury bulb purchasing plan and bulb recycling work together to protect the environment.
Michael Arny has been working on energy, environmental and sustainability issues for more than 25 years. He founded the charitable nonprofit organization Leonardo Academy in 1997 to advance sustainability and to put the competitive market to work on improving the environment. Michael Arny leads Leonardo Academy’s work on developing new tools, strategies and metrics for advancing sustainability and helps companies, organizations, families and individuals take action to improve the environment and increase sustainability.
