How Effective Are LCA Studies in Building Code Evaluation?

Nov. 29, 2011

A Life Cycle Assessment (LCA) study can be a useful way to identify improvements to a product or process.  Essentially the goal of LCA is to compare the full range of effects to provide a sound basis for reducing a product or process’s impact on the environment. But how effective are LCA studies when applied to building codes?

A Life Cycle Assessment (LCA) study can be a useful way to identify improvements to a product or process.  Essentially the goal of LCA is to compare the full range of effects to provide a sound basis for reducing a product or process’s impact on the environment. But how effective are LCA studies when applied to building codes?

When done correctly, LCA has a clearly defined scope and objective. A well-designed LCA also incorporates an understanding of the unique local, regional, and global impacts and influences surrounding the product or process.

However, LCA studies—even unique ones that conform to International Standards Organization (ISO) standards—have significant limitations when applied to building construction codes and regulations.

Those limitations often are compounded by the use of computerized LCA tools. That’s because the basic requirements necessary to conduct a legitimate LCA study that adheres to ISO standards simply cannot be distilled into a convenient software program. Unfortunately, they also create other complications that open the door to subjectivity and uncertainty.

LCA Comes Up Short For Product Evaluation in Building Codes

In terms of overall usefulness, a LCA may be a perfectly legitimate tool for a manufacturer to use in assessing building products, and possibly to compare products within the same category. It also may have benefits for products outside of building construction, where the use phase of a product’s life cycle is a much less dominant variable than with a building.

LCA introduces new challenges when used to assess a building product’s impact in terms of its emissions into air and water and in terms of its effects on human health and the environment in general over the life of a building.

In a building frame, for example, the emissions due to building materials represent at most 3% to 5% of the total emissions of the building during its life. In this case, the vast majority of emissions are not due to the building material, but due to the operation of the building.

In general, the ability to influence emissions by conducting an LCA for a building’s structural system will be less than about 1% of emissions over the life of a building—well outside the acceptable statistical limits of LCA methodology. An LCA in this case will lead to poor decision-making if applied to structural materials.

There is no actual “correct” answer with an LCA study, only relative points of comparison. This is one of many reasons why the scope of ISO 14400 warns against the use of LCAs for regulatory purposes: The standard states that there is no scientific basis for reducing LCA results to a single overall score or number.

Part of the problem is that data that complies with ISO 14044 is not available to conduct LCAs on a routine basis for major building structural materials, despite the presence of Life Cycle Inventory (LCI) databases compiled by reputable organizations.

The LCA databases that do exist use industry average data for major building materials. Unfortunately, this data is not even close to representative for a given manufacturing plant. For some materials like steel, the data is based on Canadian data from over a decade ago, ignoring the vast improvements the industry has made in reducing energy use per ton of steel in the same time frame in the United States.   

When it comes to assessing building materials, such data will produce meaningless LCA results—and may lead to the approval of construction projects that use products from manufacturers who are anything but green.

LCA Studies Ill-Suited To Use In A Regulatory Environment

The selection of specific impacts in an LCA study is a subjective act, and subject to manipulation and abuse. This fact alone makes LCA studies ill-suited to use in a regulatory environment.

Proponents of one product, for example, may push for LCA schemes that make other materials look bad. And in fact, there is no scientific method inherent in an LCA to allow decision-makers to determine one product is better than another in a building. Therefore, they must resort to some level of subjective decision-making. This opens the door to using the LCA to mask bias and abuse.

With regard to buildings, the same limitations that apply to LCAs apply to LCA software tools. Existing ”simplified” tools do not account for complete life cycle impacts, and none of them comply with ISO 14040. They do not, for example, address human health and all aspects of the natural environment require of the standard.

Shortcut LCA tools only further exacerbate the problems with representative data in further violation of ISO standards. For example, a valid LCA study should be a customized and detailed study that accounts for flows and impacts at all levels. But LCA as it currently is being practiced through existing and proposed software tools is not capable of providing that kind of assessment. Tools developers basically ignore local and regional issues. The results these tools produce can be misleading at best and a disaster at worst.

Omitting Key Factors

There are other weaknesses. For example, an LCA conducted using non-representative or nonspecific data assumes all emissions of the same pollutant are equal—even though this violates well-established principles of pollution control science. In the case of a water pollution release, an LCA might omit any number of critical factors—such as the conditions of the surrounding environment prior to a pollutant’s release, the pollutant’s release rate, and whether the release is a point or non-point release.

Another key shortcoming of LCA use for regulatory purposes is that LCA results are not reproducible among different tools and methods, or among different practitioners. The proponents of LCA tools for regulatory purposes appear to accept the notion that a methodical approach is equivalent to a valid scientific approach. But a method based on mathematical principles is not a valid scientific tool if it is not reproducible by independent parties.

In fact, the developers of LCA tools readily admit that one cannot compare results across their tools. Furthermore, they acknowledge that the results produced by those tools cannot be verified against a known correct answer. Thus, LCA shortcut tools violate basic scientific principles.

This lack of reproducibility is extremely problematic for regulators and code officials, because a project approved under one software tool may not receive the same treatment under another tool. Users could shop around for favorable results. Furthermore, results from several LCA tools could all be equally bad, equally good, or vary considerably, since the results are relative to some unknown “correct” answer.

And that simply is not enough to justify the use of LCA for buildings. Just because one product performs better than another, it does not mean that one product is a good performer, or that another product is a poor performer. In fact, it is possible that both products are harming the environment—or that both have little or no negative effect.

Some of the most misleading conclusions can occur when an LCA study or tool does not consider significant impacts. Those impacts that are omitted may be the most detrimental to the environment, but may never be known.  This explains how one industry can produce an LCA study proclaiming their product as superior to alternative products and their competitors do the same thing.  How can they both be correct?

In conclusion, regulators must decide whether they are willing to adopt LCA tools or processes that produce nice-sounding scores or other quantified results, even though—in some or even many cases—those results will lead them to approve projects that actually harm the environment.

Regulators also must ask themselves if it reasonable to burden building owners and designers with costly and time-consuming LCA studies—even if those studies produce results that may be meaningless.

There are many ways to improve the environmental impact of buildings.  Rash adoption of methods of questionable value is not one of them.  It’s time for the suppliers and manufacturers in the building industry to stop trying to use tools like LCA to position their product as superior to other products. Instead, the industry should focus on improving the environmental performance of all products and let the market decide which product is best for a given product.

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