Data on the Composition Analysis of Construction Waste & Demolition. Debris the municipal waste Stream es- Town, with the second sort planned

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1 overview of the results of the first three-week waste sort activity orga- (C&D waste) generated in the Long nized and managed by GBB staff Island Community of 225,000 and conducted from July 12 to July people. Altho%hC&Ddebriscom- 30, It is the first of a two Prises a relatively Small Portion of season sort to be conducted in the Debris the municipal waste Stream es- Town, with the second sort planned Data on the Composition Analysis of Construction Waste & Demolition Prepared By Gershman, Bnckner & Bratton, Inc. Falls Church, VA One of the largest areas of concern for the nation s demolition contractors is what to do with their waste stream. Gone are the days of cheap landfill space and low transportation costs. What was once a minor bid item has become a major cost component of any demolition project. As the NADC, the demolition industry and government regulatory agencies wrestle with this problem it is important to develop a clear understanding of what is being disposed of and what can be recycled. The following study performed by GBB, a solid waste management consultant from Falls Church, VA for the New York State Energy Research and Development Agency oflers some insight into the problems the industry faces and the methods available to deal with them. The New York State Energy Research and Development Authority (Energy Authority) has provided funding to the Town of Babylon, NY in the form of cost sharing for the investigation of recycling and tracking of construction waste and demolition debris hated by the Wood Fraction of Sample EPA to be 10 to 20 % of total Municipal Solid Waste [MSW]), it is difficult to manage through traditional waste management methods due to its bulky nature. Therefore, in order to develop efficient C&D debris management/ recovery systems, accurate methods to quantify its presence and composition must be developed. As part of the overall study, which includes the development and demonstration of a municipal tracking program and gathering data on existing disposal and recycling practices in the town for C&D waste, the project includes a composition analysis of waste materials generated from construction & demolition projects. This refinement of data will help ensure that recovery systems and associated market development efforts can be to be conducted in October, The article describes the type of construction and demolition projects that were selected for sorting and a review of the data and results from this July 1993 activity. DESCRIPTION OF SORT PROCEDURES AND SELECTED PROJECTS The sorting was conducted inside the Construction and Demolition Processing Building (C&D Building) at the Commercial and residential Recycling Facility (CRRF) located in Babylon. The CRRF is a privately owned recycling and waste transfer facility built and operated under a 20-year Service Agreement with the Town. Based on a separate CRRF utilization agreement entered into between the Town and the private owner/operator, the GBB project team used a portion of the C&D Building for the waste sort. Approximately 5,000 sq. ft. of floor space was used inside the C&D Building for both the stockpiling of the C&D waste and conducting the actual sort. Approximately six to seven sorters were used each day to pick through the material, weigh each of the sorted components, perform screening and sizing functions on certain loads, and 1 O*DEMOLITION AGE*9/93

2 conduct other sort related operations. A small slud steer and forklift were used periodically to move the C&D waste for sorting access as well as to load and unload the larger containers for weighing and ultimate materials deposition. Three 20 cu. yd. roll-offs were provided by the CRRF operator to hold certain categories of sorted material; these were for wood, ferrous and non-ferrous metals, and all other sorted waste. Additionally, for two of the delivered C&D waste loads, a fourth roll-off container was provided for handsorted cinder blocks, concrete and bricks. Due to the higher C&D debris tipping fees charged by Babylon at the CRRF versus locally available C&D debris landfills, the CRRF is not currently receiving regular commercial deliveries of C&D waste. However, deliveries were coordinated by the Town of Babylon for the C&D waste brought in during the three-week sort period. Extensive efforts were made by the GBB Project Team prior to the field work to identify construction and demolition projects for inclusion in the sorting project. This identification included a review of recently approved construction permits in the Town, current property inspections then being conducted by the Town s Building Department, site visits, if possible, and conversations with the local contractors and haulers. The actual waste deliveries and sorting was done from 7:OO a.m. to 3:30 p.m., Monday through Friday for three consecutive weeks. In summary, samples from five project categories were included in the July sorting program and more than one source of each of five project categories were sampled. This data is summarized in Table 1. A total of 16 projects were sorted from 8 residential and 8 commercial projects, comprising a total of tons. On average, about 1 1 tons were sorted each day. Given an average crew size of six laborers and an eight hour day, the sorting rate averaged 1.3 tons per hour i.e. about 450 pounds per sorter per hour. If the demolition projects were excluded, which consisted of relatively dense material, the average sorting rate was about 350 pounds per sorter per hour. For the four demolition projects which comprised 58.6 tons, the average sorting G55 Sampling Team rate was about 600 pounds per hour. Commercial building renovations were the most common type of construction activity in the Town at the time of the July sort and became the most frequently sampled category. Six such projects were analyzed comprising 68.9 tons, or about 43% of the total quantity sorted. These commercial renovations ranged from interior retail space upgrading to exterior remodeling and refurbishment. Four residential renovations were sorted and consisted of 20.1 tons. Two residential demolition projects were sorted, totalling over 38 tons of material. This category had the greatest density of material and consisted of a lot of concrete from basement flooring and cinder block walls. One single family house was completely demolished and a pre-demolition audit to estimate the quantity of C&D waste materials was conducted by GBB staff on this structure. REVIEW OF SORTED PROJECTS FROM PERMITS AND VISUAL INSPECTIONS The GBB project team tried to make a site visit, take photographs and/or gather construction permit information of the various projects included in the sort. This was accomplished for a majority of the projects and found to be useful in assessing the resultant composition data. Table 2 presents a summary of the sorted projects and the Sample Number Identifications assigned to each. The residential construction consisted of single-family homes and one multi-family building. The four residential renovations ranged from small add-ons to existing single-family homes to interior upgrading and remodeling. The type of specific renovation conducted dictated the type of waste being generated. For example, a new addition would include many typical components of a new home construction (dimensional lumber, plywood, drywall, insulation, etc.) whereas, a project involving the installation of a new roof or addition of new siding would generate only limited variety of materials. The one house demolition project that was included in the waste sort consisted of a one story single-family cottage frame house. For the 8 commercial sector projects, six were renovations and two demolitions. Much like the residential renovations, a variety of projects were included which generated specific waste types and materials. They varied from retail interior renovations (e.g., to accommodate a new 11. DEMOLITION AGE 9/93

3 loading it into the roll-off containers. The bulldozer's steel tracks shredded the C&D waste into small fragments making manual sorting difficult. Given the large percentage of miscellaneous fines (32%), the GBB Project Team decided that some additional analysis of this component should be made to assist in later related activities. After all the large components of Sample 16 were sorted off the tipping floor and weighed, two separate manual screening methods were undertaken on the remaining "miscellaneous fines" component. The first involved the field construction of a nominal 3'x3' wood frame doubedeck screen constructed with support legs to discharge at a height compatible with the field bins. The screen was constructed with a top deck of 1/2" square hole screen cloth and a bottom deck with 1/4" square holes. Material was manually loaded (by shovels) onto the top screen such that three products were produced - greater than 1/2", a middlings fraction of 1/4" -1/2", and a fines fraction less than 1/4". The results from the first screening of over 4,000 lbs. of the Sample 16 "miscellaneous fines" were as follows: Size Weieht % Den. >112" 1, " - 112" ,350 < 1/4" Total 4, ,450 A sample of the oversized (i.e., that greater than 1/2") material from the screening operation was then sorted a second time by two GBB Project Team Staff on a flat 4' x 8' sorting table to get a general sense of this smaller sized material, i.e., typically 1/2" - 3" in size. The results of this additional hand picking activity were as follows: ComDonent Composition % Concrete/rocks 32 wood 15 Roofing Material 7 Drywall 2 Metals - 2 Subtotal 58 Misc. Leftovers 42 Total 100 The miscellaneous leftovers were mostly shredded wood, drywall, paper and small stones that were greater than 1/2" but, because of their volume, could not easily be further sorted (by hand) within a reasonable time frame. In order to attempt to increase the hourly manual screening capacity of the sorters, a second larger deck screen was constructed in the field. The screen deck was approximately 12' long and 3' wide and was constructed with miscellaneous on-site materials of the CRRF operator consisting of nominal 3" x 3" angle iron used for the horizontal bracing and two higher quality (Le., thicker and stronger) but slightly different shaped screen cloth. Approximately 7,500 lbs. of miscellaneous fines was screened and, as it turned out, the second screening program presented similar results to the initial smaller-sized screen. The majority of the material in the "miscellaneous fines" category were in fact small dirt-like fines, less than 1/4" material, with about 75% of the total material screened being less than 1/2 inches. For Sample Number 16, these fines consisted mainly of dirt and small rocks dug up by the bulldozer during the demolition. Visually, these materials appeared relatively clean and pending chemical analysis (which is not part of the contract scope) could possibly be reused as a soil amendment, landfill cover, road construction, or some other uses for soil. 2. Commercial Within the commercial sector, 6 building renovations and 2 building demolition were sorted and analyzed. Like the residential sector, the demolition projects had a high percentage of miscellaneous fines, (55%), along with wood (17%) and pressboard/chipboard (12%). The largest components in the renovation projects were concrete (22%) and cinder blocks (19%). Commercial renovations were the most common type of construction activity in Babylon in July of Given that the town has very little undeveloped land for commercial projects, commercial renovations are expected to continue to be a predominant form of commercial construction activity in the town. In summary, the Babylon project involves several seasonal C&D debris waste sorts and the establishment of a new construction waste and demolition debris (C&D waste) waste audit and tracking system within the town. Figure 2 presents the summary of the major waste components from the July 1993 sort. Over 160 tons of C&D waste were sorted in July, 1993 and an additional three week sort will also be conducted by GBB in October, The refinement of such C&D debris data will help ensure that proposed recovery systems and associated material and/or energy market development efforts are tailored to best meet the needs of the community. The data presented in this article was provided by Robert H. Brickner, Vice President of GBB with the permission of the New York State Energy Research and Development Authority and the Town of Babylon, New York. It presents an in-depth look at the type of waste the demolition industry handles in an typical American city and is useful as part of the industry's ongoing program to develop recycling options for its waste. It also provides regulatory agencies with additional information on the true nature of the demolition industry's waste. 13. DEMOLITION AGE 9/93

4 tenant or space use) to a major roofing job. Table 2 presents a brief description of each project by Project Type. The density of certain material delivered loads was calculated for some of the samples and is shown in Table 3. Generally, the materials from the demolition projects were found to be of greater density than the renovations. ANALYSIS OF RESULTS The data from the sorting of the 16 projects were analyzed in a variety of ways including: Composition by Component in Each Sector Combined Composition of All Samples Combined Composition of All Residential Samples Combined Composition of All Commercial Samples Table 4, which reflects over 40 individual components sorted, provided the results for all samples. The largest component by weight was miscellaneous fines (29%), followed by concrete without rebar (14%), untreated and unpainted wood (13%), and cinder block (12%). The component miscellaneous fines dominates because nearly every sample had some fines and small fragments that could not be easily sorted and the four demolition projects had a large fraction of such fines (e.g., dirt, crushed concrete, etc.). The GBB Project Team was careful not to casually lump materials into this component. It is worth noting that Sample 16 alone had nearly ten tons of miscellaneous fines. This demolition project employed a dozer that ran over the material to increase material densities prior to loading into the contractor s roll-off boxes. The nature and size of the miscellaneous fines was analyzed, in part, during the waste sort and is discussed later in this article. The second most common component, by weight, is concrete without rebar followed closely by cinder blocks. These are fairly dense materials contributing their high percentages and were found frequently in various types of renovations and demolitions. No project generating reinforced concrete was hand sorted during the three week July sort. Visually,- wood was clearly the dominant waste component. Oftentimes an entire load would be dumped on the floor and appear to be all wood, when in fact the heavier materials had settled to the bottom of the pile. If all of the six wood categories are combined, the total overall wood composition, by weight, is 19.8%, Standard 2x4s were the most common type of wood, followed by 4x4s and other dimensional lumber sizes. Plywood comprised about 3% of the total composition by weight, but visually seemed to be a more predominant material type than the actual weight indicated. The ferrous and nonferrous metals (3.1%) consisted mostly of interior framing, shelves, and small structural members. Electrical wiring, electrical fixtures and metal drums were sorted as separate categories. All metal-related components comprised 4.5% of the total material sorted. COMPOSITION DATA BY SECTOR AND PROJECT TYPE In looking at the composition results by sector - residential and commercial - one can see several key differences. Miscellaneous fines and wood made up a larger fraction of the residential projects (59%) than commercial projects (39%) and reflects the large contribution from the residential demolitions. Concrete was more prevalent in the commercial loads as was cinder blocks. Most of these differ- ences can be attributed to the mix of project types e.g. 6 commercial renovations were sorted versus 4 residential renovations and 2 new home constructions. 1. Residential Within the residential sector, several distinctions can be made between the three project types - construction, renovation and demolition. The demolition jobs were found to have much more concrete and cinder blocks than the other two groups - a combined 32% for the demolition jobs versus an average of only 3% for renovations and construction. This is because the demolitions involved the removal of the structure s entire foundation and basement walls, whereas new residential construction and renovation jobs typically generate only leftover pieces of block for example, and unused materials left at the jobsite. The total wood fraction varied from 24% in residential demolitions to 33% in residential renovations. The composition of drywall was almost identical at about 12% for both residential construction and renovation. Roofing shingles were 11% of the residential renovation composition versus less than 2% for the other categories. This was because one of the samples (#14) was a major roofing job. This points out again the difficulty in making broad conclusions about the overall results - they are highly dependent on the specific construction and demolition activity in the sort. For the one major home demolition project - Sample Number 16 - some special sorting techniques were used to better characterize the large quantity of miscellaneous fines. As noted earlier, a large amount of fines were produced from this job because the demolition contractor used a bulldozer not only in tearing down the house but also in grinding up the C&D waste prior to 12=DEMOLITION AGE=9/93

5 I I I 1 20 yd3 20 yd Roll-Off Roll-Off Other Metals Roll-Up Doors 90-Gallon Toters 0 Truck Entrance for Sort Materials n Bins 0 Sorting Area 0 (2 yd3) Material Staging Area for Non-Sort Debris 200 ft L Town of Babylon, New York Not To Scale CONSULTANTS

6 ~ Figure 2 Summary of Major Components Met a I-F e r ro us (3.7 Yo Drvwal I/S heet roc k (4.6 YO \ \ Misc. Fines (29.0%) cot icrete wil :hout Rebar (14.( Cinder. Block (12.4%) Brick (1.3 3oofing Material-S hir igles (2. 1 Yo) -d/chip boa rd (3.0 yo) Table 2. Sample Idedfhtb md Weight W Commercial Renovation Commercial Renovation 3 I Commercial Renovation I I Residential Construction I I 1 5 I Residential Renovation 6 I Residential Renovation I Commercial Renovation I Commercial Renovation 5.5 Residential Construction I Commercial Demolition I Commercial Demolition Residential Renovation Commercial Renovation 11'5 5.5 I 14 I Residential Renovation I Table 3. Comparison of Delivered Weight and Roll-Off Containex Size Project Type Commercial Renovation Residential Renovation Commercial Demolition Residential Demolition I I Deliwered I Contaiueds) I Sample Weight Volume. v.04 (Cu.Yd.) Table 1. rhmrmaay of Project Typea pnd Weights A d Numbex of Total Weight Percent of project cptegory Project Sorted CTOns) Tdal Residential New Construction Residential Renovation Residential Demolition Commercial Building Renovation TOTAL Total

7 1 1 Composition by Category in Each Sector Table 4. Composition by Category in Each Sector (For 16 Projects Sorted)

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