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what are life cycle costs?

 

What are life cycle costs?
A life cycle cost analysis is a powerful tool used to make economic decisions for selection of building materials and design. This analysis is the practice of accounting for all expenditures incurred over the lifetime of a particular structure. Costs at any given time are discounted back to a fixed date, based on assumed rates of inflation and the time-value of money. A life cycle cost is in dollars and is equal to the construction cost plus the present value of future utility, maintenance, and replacement costs over the life of the building.
benefit of concrete life cycle costs
A life cycle assessment includes the mining of all raw materials used for building materials and as fuel for heating and cooling. (PCA No. 14895)Using this widely accepted method, it is possible to compare the economics of different building alternatives that may have different cash flow factors but that provide a similar standard of service. Quite often, building designs with the lowest first costs for new construction will require higher maintenance and generate higher energy costs during the building’s service life. Thus these buildings will have a higher life cycle cost. Conversely, durable designs often have a lower life cycle cost. In the world of selecting the lowest bid, owners need to be made aware of the benefits of a lower life cycle cost
 
The service life of building interiors and equipment is often considered to be 30 years, but the average life of the building shell is in the range of 50 to 100 years. LCC studies that use too short of a service life, for example 20 years, produce skewed results. Such studies overstate the cost of construction materials and understate the cost of maintaining and operating the building. When an LCC Study is done correctly, the long term cost benefit concrete provides is obvious.
What is Life Cycle Assessment?

 

What is life cycle assessment?
A life cycle assessment (LCA) is an environmental assessment of the life cycle of a product. An LCA looks at all aspects of a product’s life cycle—from the first stages of harvesting and extracting raw materials from nature, to transforming and processing these raw materials into a product, to using the product, and ultimately recycling it or disposing of it back into nature. The LCA of a building is necessary to evaluate the environmental impact of a building over its life.
 
An LCA of a building includes environmental impacts due to:
 
 
  • Extraction of materials and fuel used for energy;
     
  • Manufacture of building components;
     
  • Transportation of materials and components;
  • Assembly and construction;
  • Operation, including energy consumption, maintenance, repair, and renovations; and
  • Demolition, disposal, recycling, and reuse of the building at the end of its functional or useful life.
A full set of impacts includes land use, resource use, climate change, health effects, acidification, and toxicity.
 
An LCA involves a time-consuming manipulation of large quantities of data and is best done by LCA Practitioners. SimaPro (PRé Consultants, Amersfoot, the Netherlands) is an example of an LCA model. It provides data for common building materials and options for selecting LCA impacts. To get a complete picture of environmental impact, however, it is necessary to perform a separate analysis of annual heating, cooling, and other occupant loads. This is frequently accomplished using a program such as DOE2.1e.
 
There are a number of LCA Tools that have been developed for general building professionals. These simplify the analysis but have a number of challenges. The BEES software tool developed by NIST (National Institute of Standards and Technology) does not account for energy performance, and looks at individual materials only; the Athena tool, developed using Canadian data does account for energy performance, and looks at building assemblies. However neither system is complete.
 
An LCA should provide a level playing field based on a consistent methodology applied across all products and at all stages of their production, transport, use, and disposal or recycling at end of life. A number of published articles espouse the sustainability of one building product over another based on a few selected metrics instead of a full life cycle assessment (LCA). For instance, some articles representing themselves as LCA studies have used only the metrics of embodied energy or embodied CO2 emissions. These comparisons do not offer a full life cycle assessment of the product or building. A full LCA includes the effects of energy use and associated emissions over the life of the product or structure, such as climate change, acidification, materials acquisition, and human health effects.
What is the Benefit of Concrete in an LCA?
Life cycle costs and LCA include the impacts of heating and cooling a building throughout its life. (CTLGroup image)
Life cycle costs and LCA include the impacts of heating and cooling a building throughout its life. (CTLGroup image)
Concrete’s thermal mass, combined with an optimal amount of insulation, saves energy over the life of a building, thus reducing overall environmental impact. Studies show that the most significant environmental impacts are not from construction products but from the production and use of natural gas and electricity to heat, cool, and operate the buildings. The embodied energy of the construction products is approximately equal to 4 years of operational energy use. Stated another way, the operational energy use and associated emissions to air during the life of the building is 85 to 95% of the total energy and emissions.
 
A full LCA with an appropriate service life shows the benefits of using optimal amounts of insulation, thermal mass, orientation, and other energy saving features When an LCA is done properly, the long term environmental benefit concrete provides becomes evident.
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Located at BookstoreComparison of Environmental Effects of Steel- and Concrete-Framed Buildings (2005)
Angela Acree Guggemos and Arpad Horvath, Journal of Infrastructure Systems, Vol 11, page 93
Available for $25, free through subscribing institution. In order to create an environmentally-conscious building, the environmental impacts of the entire service life must be known. Life-cycle assessment (LCA), which evaluates the impacts from all life-cycle phases, from "cradle to grave," is the best method to achieve this goal. In this paper, LCA is used to quantify the energy use and the environmental emissions during the construction phase of two typical office buildings, one with a structural steel frame and one with a cast-in-place concrete frame, and then these are put in the perspective of the overall service life of each building. The concrete structural-frame construction has more associated energy use, CO2, CO, NO2, particulate matter, SO2, and hydrocarbon emissions due to more formwork used, larger transportation impacts due to a larger mass of materials, and longer equipment use due to the longer installation process. In contrast, the steel-frame construction has more volatile organic compound (VOC) and heavy metal (Cr, Ni, Mn) emissions due to the painting, torch cutting, and welding of the steel members. The energy use and the environmental emissions of the two buildings are comparable if the total impacts from materials' manufacturing, construction, transportation, use, maintenance, and demolition are considered. Energy use and environmental emissions from office buildings can be reduced through a careful selection of embedded and temporary materials and construction equipment.
Located at BookstoreConcrete: Sustainability and Life Cycle (2007)
Portland Cement Association. Item Code: SN3011
Available for download for free This report presents the results of the LCI of three concrete products: ready mixed concrete, concrete masonry, and precast concrete.
Located at BookstoreLife Cycle Assessment of a Concrete Masonry House Compared to a Wood Frame House (2002)
Medgar L. Marceau and Martha G. VanGeem, Portland Cement Association Item Code: SN 2572, 168 pages
Available for free download. This report is an update of Life Cycle Assessment of an Concrete Masonry House Compared to a Wood Frame House (Marceau and VanGeem 2002). It presents the results of an assessment of the environmental attributes of concrete construction compared to wood-framed construction. A life cycle assessment (LCA) was conducted on a house modeled with two types of exterior walls: a wood-framed wall and a CMU wall. The LCA was carried out according to the guidelines in International Standard ISO 14044, Environmental Management - Life Cycle Assessment - Requirements and Guidelines. The house was modeled in five cities, representing a range of U.S. climates: Lake Charles, Tucson, St. Louis, Denver, and Minneapolis. The 228-square meter (2450-square foot), two-story, single family house has four bedrooms and a two-car garage. The system boundary includes the inputs and outputs of energy, materials, and emissions to air, soil, and water from extraction of raw materials though construction, maintenance, and occupancy. The house energy use was modeled using DOE-2.1E and the life cycle impact assessment was modeled using SimaPro. The results show that for a given climate, the life cycle environmental impacts are similar for the wood and CMU houses. The most significant environmental impacts are not from construction materials but from the production of electricity and natural gas and the use of electricity and natural gas in the houses by the occupants.
Located at BookstoreLife Cycle Assessment of an Insulating Concrete Form House Compared to a Wood Frame House (2002)
Medgar L. Marceau and Martha G. VanGeem, Portland Cement Association, Item Code: SN 2571, 167 pages
Free to download. This report is an update of Life Cycle Assessment of an Insulating Concrete Form House Compared to a Wood Frame House (Marceau and VanGeem 2002). It presents the results of an assessment of the environmental attributes of concrete construction compared to wood-framed construction. A life cycle assessment (LCA) was conducted on a house modeled with two types of exterior walls: a wood-framed wall and an ICF wall. The LCA was carried out according to the guidelines in International Standard ISO 14044, Environmental Management - Life Cycle Assessment - Requirements and Guidelines. The house was modeled in five cities, representing a range of U.S. climates: Miami, Phoenix, Seattle, Washington (DC), and Chicago. The 228-square meter (2450-square foot), two-story, single family house has four bedrooms and a two-car garage. The system boundary includes the inputs and outputs of energy, materials, and emissions to air, soil, and water from extraction of raw materials though construction, maintenance, and occupancy. The house energy use was modeled using DOE-2.1E and the life cycle impact assessment was modeled using SimaPro. The results show that for a given climate, the life cycle environmental impacts are greater for the wood house than for the ICF house.
Download DocumentAchieving Sustainability with Precast Concrete (2006)
VanGeem, Martha. PCI Journal, January-February 2006. 20 pages
Available for free download courtesy of the Precast/Prestressed Concrete Institute. Sustainability is often defined as development that meets the needs of the present without compromising the ability of future generations to meet their own needs.1 While other building materials may have to alter their configurations, properties, or both to be applicable to sustainable structures, precast concrete’s inherent properties make it a natural choice for achieving sustainability with today’s new buildings. In this paper, sustainability concepts are outlined and different rating systems for evaluating sustainable design are introduced. Finally, ways are provided in which precast concrete meets or exceeds one rating system’s requirements to achieve sustainability.
Download DocumentLife Cycle Cost Literature Survey (2000)
Katie Amelio and Martha G. VanGeem, PCA R&D Serial No. 2484, Portland Cement Association, 41 pgs
Available for free. Life cycle cost analysis is currently a valuable tool in the construction industry and will become more so as resources become more scarce. Selecting the materials and components of structures and pavements based on a life cycle cost analysis can significantly decrease the lifetime cost of construction, maintenance and repair. This literature survey gathers life cycle cost information for concrete and competing materials from a variety of sources, summarizes the results, and describes the resulting searchable database. The database is a resourceful tool for those who would like to obtain additional information on life cycle cost analysis and results. The searchable life cycle cost database with abstracts, in Filemaker Pro® format, is available to Portland Cement Association (PCA) member companies, PCA staff, and cement promotion groups.
Download DocumentLife Cycle Inventory of Slag Cement Concrete
Jan R. Prusinski, Medgar L. Marceau and Martha G. VanGeem, Slag Cement Association, 26 pages
Available for free. Technical papers providing background and references for life cycle inventory data on slag cement and concrete made with slag cement.
Download DocumentSustainable Manufacturing Series - Tire-Derived Fuel (2005)
Portland Cement Association, #IS 325, 4 pages
Available for free. The safe and beneficial use of scrap tires as an alternative fuel source for cement kilns is highlighted in this 4 page color brochure.
Located at External Web SiteConcrete's Contrubition to Sustainable Development
Concrete is the most widely used building material on earth. It has a 2, 000 year track record ofhelping build the Roman Empire to building today's modern societies. As a result ofits versatility, beauty, strength,·and durability, concrete is used in most types ofconstruction, including homes, buildings, roads, bridges, airports, subways, and water resource structures. And with today's heightened awareness and demandfor sustainable construction, concrete performs well when compared to other building materials. Concrete is a sustainable building material due to its many eco{riendly features. The production ofconcrete is resource efficient and the ingredients require little processing. Most materials for concrete are acquired and manufactured locally which minimizes transportation energy. Concrete building systems combine insulation with high thermal mass and low air infiltration to make homes and buildings more energy efficient. Concrete has a long service life for buildings and transportation infrastructure, thereby increasing the period between reconstruction, repair, and maintenance and the associated environmental impact. Concrete, when used as pavement or exterior cladding, helps minimize the urban heat island effect, thus reducing the energy required to heat and cool our homes and buildings. Concrete incorporates recycled industrial byproducts such as fly ash, slag, and silica fume that helps reduce embodied energy, carbon footprint, and waste.