California Green Building Code (CALGreen) – Life Cycle Assessment

By designing buildings with extended life cycles, this technique seeks to indirectly conserve energy and resources. The organisations listed in the code are producing and gathering data on many kinds of materials and systems. It is obvious that this data gathering must continue for numerous generations in order to do long span life cycle analysis. Only then will the cost and life cycle be measured, resulting in a more accurate data set for the most efficient materials and processes.

Life Cycle Assessment

CALGreen Code Section A5.409.1: General.

Life cycle assessment shall be ISO 14044 compliant. The service life of the building and materials assemblies shall not be less than 60 years, unless designated in the construction documents as having a shorter service life as approved by the enforcing agency.

CALGreen Code Section A5.409.2: Whole building life cycle assessment.

Conduct a whole building life assessment, including operating energy, showing that the building project achieves at least a 10 percent improvement for at least three of the impacts listed in Section A5.409.2.2, one of which shall be climate change, compared to a reference building of similar size, function, complexity and operating energy performance, meeting the 2019 California Energy Code at a minimum.

CALGreen Code Section A5.409.2.1: Building components.

The building envelope, structural elements, including footings and foundations, interior ceilings, walls, and floors; and exterior finishes shall be considered in the assessment.


1. Plumbing, mechanical and electrical systems and controls; fire and smoke detection and alarm systems and controls; and conveying systems.

2. Interior finishes are not required to be included.


1. Software for calculating whole building life cycle assessments includes those found at the Athena Institute website (Impact Estimator software), the PE International website (GaBi software), and the PRe Consultants website (SimaPro software).

2. Interior finishes, if included, may be assessed using the NIST BEES tool.

CALGreen Code Section A5.409.2.2: Impacts to be considered.

Select from the following impacts in the assessment:

1. Climate change (greenhouse gases).

2. Fossil fuel depletion.

3. Stratospheric ozone depletion.

4. Acidification of land and water sources.

5. Eutrophication.

6. Photochemical oxidants (smog).

CALGreen Code Section A5.409.3: Materials and system assemblies.

If whole building analysis of the project is not elected, select a minimum of 50 percent of materials or assemblies based on life cycle assessment of at least three for the impacts listed in Section A5.409.2.3, one of which shall be climate change.

Note: Software for calculating life cycle assessments for assemblies and materials may be found at the Athena Institute website and the NIST BEES website.

CALGreen Code Section A5.409.4: Substitution for prescriptive standards.

Performance of a life cycle assessment completed in accordance with Section A5.409.2 may be substituted for other prescriptive Material Conservation and Resource Efficiency provisions of Division A5.4, including those made mandatory through local adoption of Tier 1 or Tier 2 in Division A5.6.

CALGreen Code Section A5.409.5: Verification of compliance.

Documentation of compliance shall be provided as follows:

1. The assessment is performed in accordance with ISO 14044.

2. The project meets the requirements of other parts of Title 24.

3. A copy of the analysis shall be made available to the enforcement authority.

4. A copy of the analysis and any maintenance or training recommendations shall be

included in the operation and maintenance manual.


The intent of this measure is to indirectly conserve energy and resources by creating buildings with a longer life cycle. If one building lasts 100 years and a similar occupancy building lasts a mere 30 years, the energy and resources to rebuild that particular building will be saved twice by merely increasing its usefulness (life cycle) by a factor of 3. Data are being created and collected on various types of materials and systems by the organizations named in the code. For long span life cycle analysis, the collection of this data clearly needs to continue over several generations. Only then can the cost along with the life cycle be quantified, so a more objective data set will exist for the “most” efficient materials and systems for a given use.

Compliance Method:

The generation of cost to life cycle analysis (LCA) is in its early stages. This type of analysis is by definition a very lengthy process. Until the energy and resources to produce a material or product is fully quantified, then objectively joined to the life cycle of the materials and products, an accurate overall efficiency may be placed on the cost to life cycle ratio, which will help designers make the best choices for specified materials and products. There are software programs available that can be used to calculate LCA, some of which are noted in this code section.


Plan intake: The plan reviewer should confirm in the construction documents support data for materials and products intended to create a longer life cycle; a database instituted to keep information on the projected life cycle vs. actual life cycle will provide the means of knowing which types of buildings have a superior overall energy and resource efficiency when compared to less durable construction materials, methods and products.

On-site enforcement: The inspector should verify that applicable standards are met in the quality of construction of buildings designed to be more durable.

(Excerpted from ‘Guide to the 2022 California Green Building Standards Code Nonresidential’ – Appendix A5)

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