2. Input Data
2.1. Scrap Collection
2.2. Steel Consumption
3. Calculation Procedure
4. Results and Discussion
4.1. Calculated Lifetimes per Industry Sector in the U.S.
4.2. The Lifetimes of Steel in the U.S., Sweden, and the World
Conflicts of Interest
|Product groups||References||Method||Timeline||Average Lifetime|
|American Housing Survey, General Housing Data, all Housing Units.||U.S. Census Bureau, Current Housing Reports, Series H150/11, American Housing Survey for the United States: 2011, Table C-01-AH. ||Lifetime of buildings used in Unites States||2015|
|American Housing Survey, General Housing Data, all Housing Units.||U.S. Department of Commerce. Bureau of Economic Analysis. Table A-1. Characteristics of the housing inventory 1973, 1980 and 1970 page 6 or page 1. ||Lifetime of buildings used in Unites States||1973|
|Industrial buildings, mobile offices, office buildings, commercial warehouses, other commercial buildings, religious buildings, educational buildings, hospital and institutional buildings, hotels and motels, amusement and recreational buildings, all other nonfarm buildings.||U.S. Department of Commerce. Bureau of Economic Analysis. Fixed Assets and Consumer Durable Goods in the United States, 1925–1999. ||Lifetime estimates||1925–1997||17–48 years|
|Bridges||National Bridge Inventory [10,11]||Lifetime of bridges in-use, maximum age distribution. Most bridges were built for a 50-year design life.||2010||50 years|
|Product Groups||Reference||Method||Timeline||Average Lifetime|
|Construction machinery and equipment, metalworking machinery and equipment, general purpose machinery and equipment.||U.S. Department of Commerce. Bureau of Economic Analysis. Fixed Assets and Consumer Durable Goods in the United States, 1925–1999. ||Service lives and depreciation estimates.||1925–1999||10–16 years|
|Agricultural and different machinery.||Division of Assessment Standards, Nevada Department of Taxation. ||Service lives.||2010||7–30 years|
|Metalworking machinery, durable machinery, special industry machinery.||U.S. Department of Commerce. Bureau of Economic Analysis. Fixed Assets and Consumer Durable Goods in the United States, 1925–1997. ||Service lives.||1925–1997||16–25 years|
|Product Groups||Reference||Method||Timeline||Average Lifetime|
|Boats and vessels—dry cargo, tanker, towboat, passenger, offshore support/crew-boats, dry barge, tank/liquid barge, (figures include vessels available for operation)||U.S. Army Corps of Engineers, Waterborne Transportation Lines of the United States, Volume 1, National Summaries, Table 4, available at http://www.navigationdatacenter.us/veslchar/pdf/ as of 21 June 2016. ||Age is based on the year the vessel was built or rebuilt.||1990–2014||18–16 years|
|Locomotives, passenger and other train cars.||Amtrak Annual Report, Statistical Appendix. ||Fiscal year-end average (30 September of stated year). Active units less backshop units undergoing heavy maintenance, less back-ordered units undergoing progressive maintenance and running repairs.||1972–2015||11–26 years|
|Commuter rail locomotives, commuter rail passenger coaches, commuter rail self-propelled passenger cars, heavy-rail passenger cars, light rail vehicles (streetcars), articulated full-small size trolley vans, ferry boats.||U.S. Department of Transportation, Federal Transit Administration, National Transit Database. National Transit Summaries and Trends, Table 25. ||Average Age of Urban Transit Vehicles. Locomotives used in Amtrak intercity passenger services are not included.||1985–2014||11–16 years|
|Aircraft: Transportation by air, depository institutions and business services.||U.S. Department of Commerce. Bureau of Economic Analysis. Fixed Assets and Consumer Durable Goods in the United States, 1925–1999. ||Average age of aircraft.||1960–1997||15–20 years|
|Product Groups||Reference||Method||Timeline||Average Lifetime|
|Mobile phones, cordless telephones, answering machines, fax machines, personal computers, laptops, printers, computer monitors, computer mice, keyboards (Metal content 8–69%).||Study of Life Expectancy of Home Components. Prepared by the Economics Group of NAHB. ||Current lifetime||2011||5–11 years|
|Household appliances—air conditioners, dishwashers, dryers, freezers, microwave ovens, ranges, refrigerators, clothes washers, water heaters, trash compactors (metal content in all units between 46–96%).||National Association of Home Builders/Bank of America Home Equity. ||Life expectancy is based on first-owner use.||2011||5–20 years|
|Video and audio products—projection TVs, plasma, LCD, and color TVs, TV/VCR combinations, videocassette players, VCR decks, DVD players, camcorders, home and portable audio products (Metal content 21–30%)||National Association of Home Builders/Bank of America Home Equity. ||Life expectancy is based on first-owner use.||2011||9–15 years|
|Scrap Type||Percentage of Yearly Scrap (%)|
|Electrical and Electronic products||5.8|
|Total production of scrap||19,095,547 ton|
|Steel consumption (h)||Net consumption of steel used for its application purpose plus prompt steel scrap. Marked with a thick blue curved line in Figure A1.|
|Scrap collection (f)||Net collection of obsolete and prompt steel scrap in the US. Domestic collected steel scrap which is commercially available. Marked with a thick orange curved line in Figure A1.|
|Purchased steel scrap||Net receipt of scrap in US iron and steel mills and foundries, including imports and excluding exports of scrap.|
|Internal scrap||Processing scrap generated at iron and steel mills and foundries.|
|Prompt scrap||Processing scrap generated at external manufacturers (during downstream processing); also termed “new scrap”.|
|Obsolete scrap||Old scrap which has been collected and processed from end-of-life products and applications.|
|Indirect trade||Imports and exports of steel in further manufactured goods; steel contained in products.|
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|Industry Sector||Methods||Typical Product Groups||Average Lifetime of Steel Products in Years 1|
|Construction||Average age of buildings and bridges in-use in US||Housing, industrial buildings, mobile offices, office buildings, warehouses, bridges||39 (2015) |
44 (2013 & 2014) 
42 (2011) 
50 (2010) [10,11]
17–48 (1925–1997) 
28 (1980) 
24 (1973) 
|Industry goods||Service lives of machinery and depreciation estimates||Machinery for metalworking, construction, agriculture, and special industry||7–30 (2010) |
10–16 (1925–1999) 
16–25 (1925–1997) 
|Consumer goods||Average age of appliances in-use in US||Household appliances, video and audio products, computers||5–20 (2011) |
|Automotive||Average age of automobiles and trucks in operation in the United States||Transportation by air, automobiles, locomotives, ferry boats||16–18 (1990–2014) |
11–16 (1985–2014) 
11–26 (1972–2015) 
15–20 (1960–1997) 
|Industry Sector||Reported||Input Data|
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