Full circle

Asphalt shingle recycling is gaining momentum


Recycling markets for post-consumer asphalt roofing shingles (tear-offs) are starting to gain ground. The blossoming green building movement, emphasis on environmental stewardship, increasing oil prices, aggregate shortages, efforts to decrease greenhouse gas emissions, state recycling programs and regulations, local recycling ordinances, increasing tipping (disposal) fees and difficulty choosing sites for new landfills are some drivers pushing recycling of construction and demolition materials into the limelight.

In addition, the U.S. Environmental Protection Agency's (EPA's) Resource Conservation Challenge is drawing attention to reuse and recycling of construction and demolition materials.

According to the Construction Materials Recycling Association (CMRA), an estimated 11 million tons of asphalt roofing shingles are generated annually in the U.S., and some estimates are higher. Compared with other construction and demolition materials such as metal, concrete and asphalt pavement, only a small percentage of asphalt shingle tear-offs are currently recovered, leaving significant opportunity to use recycled asphalt shingles.

The primary use for recycled asphalt shingles in the U.S. is as a road building material, particularly for use in hot-mix asphalt. Other uses of recycled asphalt shingles include cold-mix asphalt, cold patch, road base, dust control, mulch, temporary roads and fuel.

The benefits derived from using recycled asphalt shingles stem from the recovery of asphalt cement and mineral aggregate components of shingles, each of which represent about 20 to 40 percent of a shingle's weight. With the price of oil at an all-time high and aggregate shortages being experienced in some areas of the U.S., there are obvious reasons to investigate opportunities to recycle shingles.

Past progress

The national dialogue on shingle recycling dates to 1999 when the first Asphalt Shingle Recycling Forum was held in Chicago. EPA, CMRA and the University of Florida, Gainesville, partnered to undertake a review of state programs and private recyclers. This culminated in the launch of www.shinglerecycling.org, a comprehensive clearinghouse of information about the subject.

The Web site includes overviews of shingle recycling in each state (including state regulations, environmental agency contacts and all known recyclers), economics of recycling, markets for recycled shingles, pertinent environmental regulations, worker health and safety issues, a library of literature on shingle recycling and current research.

The second forum was held in 2003, and in 2005, EPA awarded a grant to CMRA to help develop markets for asphalt shingle tear-offs. The project's objectives were to document shingle recycling best practices, evaluate environmental issues associated with asphalt shingle recycling and update the Web site.

Realizing momentum was continuing to build for shingle recycling, EPA partnered with the Federal Highway Administration and CMRA to host the Third Asphalt Shingle Recycling Forum Nov. 1-2, 2007. The third forum built on the successes of the previous forums by providing more than 200 attendees an opportunity to continue the national dialogue and assess new findings, initiatives and strategies seeking to increase the recycling and recovery of asphalt shingles.

Two new publications from CMRA were introduced at the forum: Recycling Tear-Off Asphalt Shingles: Best Practices Guide and Environmental Issues Associated with Asphalt Shingle Recycling. Overviews of these documents follow; they are available in their entirety for free at www.shinglerecycling.org.

Best practices

Recycling Tear-Off Asphalt Shingles: Best Practices Guide provides a starting point for shingle recyclers to plan a new operation or improve an existing one. It focuses on business planning, recycling operations, marketing strategies and compliance recommendations and identifies three major best practices, each with a number of supporting points:

  1. Recyclers should implement quality-assurance and -control systems to carefully control the quality of their incoming supplies of shingle tear-off materials.
  2. Recyclers' end product, recycled asphalt shingles, should meet or exceed material specifications of their end markets.
  3. A recycler's business plan should include a marketing plan based on multiple outlets for recycled asphalt shingles.

The best practices guide also contains CMRA's recommended asbestos sampling protocol for shingles. By implementing the best practices, one can produce a clean material that is of consistent quality and free of nails and other debris. And, backed by test results, a recycler can guarantee a product is asbestos-free.

The best practices guide also addresses size and moisture requirements to meet or exceed state quality-assurance and -control requirements for hot-mix asphalt. These characteristics are desirable to end-users and state environmental agencies.

Environmental issues

Environmental Issues Associated with Asphalt Shingle Recycling discusses two main environmental concerns: asbestos, which occasionally is found in the fiberglass or felt mat of shingles, and polycyclic aromatic hydrocarbons (PAHs), which occur naturally in asphalt products.

The paper's authors reviewed available historical information about asbestos use in roofing products and concluded asbestos was not widely used in shingles as compared with other roofing products and that it was phased out of shingles by the late 1970s or early 1980s. In addition, the paper presents the aggregated asbestos testing data from shingle recyclers in several states.

To date, more than 27,000 tear-off shingle samples have been tested for asbestos by these processors. About 1.47 percent of those samples tested positive as asbestos-containing material, which means they contain more than 1 percent asbestos and need to be properly disposed of. Many asbestos detections have been attributed to other materials, such as mastic attached to shingles.

The paper's authors believe this frequency of asbestos detection is consistent with the fact that asbestos was mostly phased out by the early 1980s and the typical service life of an asphalt shingle is 15-25 years, meaning much of the older shingle stock already has been removed from roof systems. They recommend that by sourcing uncontaminated material, one should be able to further reduce the incidence of asbestos detection. Moreover, as the aged asphalt shingle roofing stock is replaced over time, the frequency of encountering shingles with any asbestos content will further decrease.

The authors emphasize that PAHs, which are formed primarily during the incomplete burning of coal, oil and gas, are expected to be present in asphalt shingles and hot-mix asphalt. PAHs are not expected to leach from discarded shingles. Although PAHs are emitted during typical hot-mix asphalt production, the effect of incorporating recycled asphalt shingles in hot-mix asphalt is currently unknown but is not believed to be significant.

The paper also offers recommendations to recyclers and regulators for minimizing environmental risks and worker health risks. They include detailed recommendations for recyclers' operations plans, monitoring and quality-assurance plans, and end-use plans.

Additional barriers

However, best practices alone are not enough to help shingle recycling really take off. There are a number of economic issues and market challenges to consider.

Shingles are heavy, making transportation a limiting factor in any recycling project. The recycling tipping fee must be cost-competitive for a roofing contractor to choose recycling instead of disposal. Likewise, a recycled asphalt shingle product must be priced competitively because end-users are more likely to choose a nontraditional or recycled product if it will save them money. And finally, preference for using recycled asphalt shingles varies among hot-mix asphalt plant operators.

Materials specifications also are critical for market development. State department of transportation (DOT) specifications often are relied on by county and local public works engineers and used on private jobs and DOT projects. However, only a handful of state DOTs (Georgia, Missouri and South Carolina) currently have specifications for using recycled asphalt shingles in hot-mix asphalt.

Other states (Indiana, Massachusetts, Minnesota, North Carolina, New Jersey, Pennsylvania, Texas and Virginia) have specifications for the use of manufacturers' shingle scrap in hot-mix asphalt though the volume of available manufacturers' scrap is insignificant compared with the volume of shingle tear-offs generated annually.

In states with no DOT specification for recycled asphalt shingle material, a provisional specification and recommended practice published in 2006 by the American Association of State Highway Transportation Officials (AASHTO) for using recycled shingles in hot-mix asphalt can be used. Both can be found at www.shinglerecycling.org.

Furthermore, there also is a proposed DOT pooled funds study, "Performance of Recycled Asphalt Shingles in Hot Mix Asphalt," to be conducted at Iowa State University, Ames, and University of Minnesota, Twin Cities.

The study will result in the creation of a specification that addresses quality-assurance and -control concerns with incorporating recycled asphalt shingles into hot-mix asphalt; include demonstration projects to assess performance of recycled asphalt shingles in hot-mix asphalt at varying percentages, climates and traffic levels; and create a comprehensive database of performance results of recycled asphalt shingles in hot-mix asphalt.

AASHTO's provisional specification and new specification to be developed through the pooled funds study will create additional resources for end-users seeking guidance about how to use recycled asphalt shingles in hot-mix asphalt.

Environmental benefits

As state and local governments and private companies assess their environmental footprints and create policies to minimize the environmental effects of their activities, it is becoming ever more important to understand the environmental benefits and effects associated with materials management decisions such as reuse and recycling.

Reuse and recycling often offer the benefits of energy and water savings, as well as greenhouse gas and toxic emissions reductions, because of avoided virgin material mining and processing.

EPA is completing a life-cycle analysis to quantify the environmental benefits and effects of using recycled asphalt shingles in hot-mix asphalt. The findings of this analysis will include information about avoided (or incurred) energy and water consumption; carbon dioxide, nitrogen dioxide, particulate matter, sulfur dioxide, carbon monoxide, mercury and lead emissions; and hazardous waste generation. The findings will be published in "Waste and Materials—Flow Benchmark Sector Report: Beneficial Use of Secondary Materials-Construction & Demolition Material" as early as this summer.

Other organizations are also realizing the environmental benefits of asphalt shingle recycling. For example, the U.S. Green Building Council requires a minimum of 5 percent of recycled asphalt shingles in any asphalt pavement, including roadways, parking lots, sidewalks and curbs, to earn the Green Construction & Technology: Recycled Content in Infrastructure credit in the pilot version of its LEED for Neighborhood Development rating system.

How to recycle

Recycling presents great environmental stewardship opportunities for the roofing industry. If you are interested in recycling asphalt shingles, research the resources currently available in your state, including state specifications.

You can find this information and key contacts for your state agencies at www.shinglerecycling.org under the State Experience section. Your state regulator will help you learn what can be recycled in your state and how to do it. If you want to start a recycling operation, don't learn by trial and error—you can refer to the best practices guide to glean the cumulative wisdom of the pioneers of asphalt shingle recycling.

Remember, you may be able to reduce your disposal costs by keeping asphalt shingles and other construction and demolition materials out of landfills. And substituting reused or recycled materials in place of virgin materials can result in substantial energy savings and greenhouse gas emissions reductions—and you can make that happen.

Julie Gevrenov is an environmental engineer with the U.S. Environmental Protection Agency's Region 5 office in Chicago.



A word on economics

So where's the business opportunity in shingle recycling? On the front end, you obviously can save money by recycling if a recycling tipping fee compares favorably with costs of local landfill tipping fees.

But what about recyclers and end-users, particularly hot-mix asphalt producers? In general, most private companies don't want to discuss their operations, and because local conditions such as tipping fees vary widely, no single example can be representative of all operations. But a hypothetical, conservative scenario can help reveal some information.

Assuming the asphalt shingles torn off a roof system are 20 percent asphalt, the price of liquid asphalt cement is $300 per ton and about 75 percent of the asphalt in the shingles is "available" to replace virgin asphalt cement in hot-mix asphalt, then the value of the asphalt in the recycled asphalt shingles is about $45 per ton. If we assume a recycler and hot-mix asphalt producer split the value of the recycled asphalt shingles, $22.50 per ton is paid to the recycler less about $15 per ton for processing and transportation costs, leaving the recycler with about a $7.50 per ton profit on the processing side of the operation alone.

Profitable recycling ventures need revenue from their tipping fees as well as from the sale of recycled materials. If a recycler sets his tipping fee for asphalt shingle tear-offs at 50 to 75 percent of the landfill tipping fee, there is a financial incentive for people to recycle. Recycling Tear-Off Asphalt Shingles: Best Practices Guide (which is available for free at www.shinglerecycling.org) explains that presorting can be done quite reasonably by roofing contractors—the goal isn't to remove every last nail from the shingles but to keep wood, plastic and other debris in separate piles. With the price of petroleum-based products at an all-time high, this conservative, back-of-the-envelope estimate shows that shingle recycling can be quite profitable. And the economic and environmental benefits are shared across the roofing, recycling and paving industries.

COMMENTS

Be the first to comment. Please log in to leave a comment.