Mill Valley Municipal Code Ch. 14.49 Low-Carbon Concrete Standards

A. The purpose of this chapter is to provide practical standards and requirements for the composition of concrete, as defined herein, that maintains adequate strength and durability for the intended application and at the same time reduces greenhouse gas emissions associated with concrete composition. This code includes pathways for compliance with either reduced cement levels or lower-emission supplementary cementitious materials.

B. The provisions of this chapter are applicable to the following types of construction: new buildings, construction on vacant lots, Major Remodels, construction projects involving the placement of 13 cubic yards or more of cast-in place concrete, and/or City-sponsored projects.

(Ord. 1367, 3/16/2026)

For the application of this chapter the following definitions shall apply:

A.

"Concrete"

means any approved combination of mineral aggregates bound together into a hardened conglomerate in accordance with the requirements of this code.

B.

"Environmental Product Declaration (EPD)"

means quantified environmental information on the life cycle of a product to enable comparisons between products fulfilling the same function. EPDs must conform to ISO 14025, and EN 15804 or ISO 21930, and have at least a "cradle to grave" scope (which covers product life cycle from resource extraction to the factory).

C.

"Major Remodel"

as defined in MVMC Section 14.48.030.

D.

"Upfront Embodied Carbon (Embodied Carbon)"

means the greenhouse gasses emitted in material extraction, transportation and manufacturing of a material corresponding to life cycle stages A1 (extraction and upstream production), A2 (transportation), and A3 (manufacturing). Definition is as noted in ISO 21930 and as defined in the Product Category Rule for Concrete by NSF dated February 22, 2019.

(Ord. 1367, 3/16/2026)

A. Summary of Compliance. Table 1 summarizes compliance with this chapter based on cement content and embodied carbon, as further described in subsections B through E below. Modifications to the requirements identified in the Table below may be granted through subsection F below or by seeking an exemption, as identified in Section 14.49.050.

MVMC 14.49.030-Table 1: Cement and Embodied Carbon Limit Compliance Options

Notes:

B. Cement Limit Method — Mix. Cement content of a concrete mix using this method shall not exceed the value shown in Table 1. Use of this method is limited to concrete with specified compressive strength not exceeding 5,000 psi.

C. Cement Limit Method — Project. Total cement content shall be based on total cement usage of all concrete mix designs within the same project. Total cement content for a project shall not exceed the value calculated according to Equation C.

D. Embodied Carbon Method — Mix. Embodied carbon of a concrete mix, based on an approved environmental product declaration (EPD), shall not exceed the value given in Table 1.

E. Embodied Carbon Method — Project. Total embodied carbon (ECproj) of all concrete mix designs within the same project shall not exceed the project limit (ECallowed) determined using Table 1 and Equation C.

F. Allowable Increases.

1. Cement and Embodied Carbon Limit Allowances. Cement or Embodied Carbon limits shown in Table 1 can be increased by 30% for concretes demonstrated to the Building Official as requiring high early strength. Such concretes could include, but are not limited to, precast, prestressed concrete; beams and slabs above grade; and shotcrete.

2. Approved Cements. The maximum cement content may be increased proportionally above the tabulated value when using an approved cement, or blended cement, demonstrated by approved EPD to have a plant-specific EPD lower than 1040 kg CO2e/metric ton. The increase in allowable cement content would be (1040/plant=specific EPD) %.

(Ord. 1367, 3/16/2026)

Compliance with the requirements of this chapter shall be demonstrated through the following:

A. As a condition prior to the issuance of every building permit involving placement of concrete, the permit applicant shall be required to submit a completed low-carbon concrete compliance form that shall be provided by and reviewed for compliance by the building department prior to issuing the permit.

B. As a condition of such building permits, and prior to approving construction inspections following placement of concrete, the permit applicant shall be required to submit batch certificate and/or EPDs provided by the concrete provider that demonstrate compliance with this chapter and the compliance form on file with the building permit. The batch certificates and/or EPDs shall be reviewed for compliance by the building department prior to approving any further inspections.

C. When deviations from compliance with this chapter occur the Building Official is authorized to require evidence of equivalent carbon reductions from the portions of remaining construction of the project to demonstrate alternative compliance with the intent of this chapter.

D. For projects involving placement of concrete by, or on behalf of the City of Mill Valley, specifications indicating compliance with this chapter shall be preserved in accordance with the City's document retention policy.

(Ord. 1367, 3/16/2026)

A. Hardship or Infeasibility Exemption. If an applicant for a project subject to this chapter believes that circumstances exist that make it a hardship or infeasible to meet the requirements of this chapter, the applicant may request an exemption as set forth below. In applying for an exemption, the burden is on the applicant to show hardship or infeasibility. The applicant shall identify in writing the specific requirements of the standards for compliance that the project is unable to achieve and the circumstances that make it a hardship or infeasible for the project to comply with this chapter.

Circumstances that constitute hardship or infeasibility may include, but are not limited to the following:

1. There is a lack of commercially available material necessary to comply with this chapter;

2. The cost of achieving compliance is disproportionate to the overall cost of the project;

3. Scope of work proposed for the project;

4. Compliance with certain requirements would impair the historic integrity of buildings listed on a local, state or federal list or register of historic structures as regulated by the California Historic Building Code (Title 24, Part 8).

B. Granting an Exemption. If the Building Official determines that it is a hardship or infeasible for the applicant to fully meet the requirements of this chapter and that granting the requested exemption will not cause the building to fail to comply with the California Building Standards Code, the Building Official shall determine the maximum feasible threshold of compliance reasonably achievable for the project. In making this determination, the Building Official shall consider whether alternate, practical means of achieving the objective of this chapter can be satisfied. If an exemption is granted, the applicant shall be required to comply with this chapter in all other respects and shall be required to achieve the threshold of compliance determined to be achievable by the Building Official.

C. Denial of Exception. If the Building Official determines that it is reasonably possible for the applicant to fully meet the requirements of this chapter, the request shall be denied and the applicant shall be notified of the decision in writing. The project and compliance documentation shall be modified to comply with the standards for compliance.

D. Appeal. Any aggrieved applicant or person may appeal the determination of the Building Official regarding the granting or denial of an exemption or compliance with any other provision of this chapter. Any appeal shall be filed in writing with the Building Official no later than 14 days after the date of the determination. The appeal shall state the alleged error or reason for the appeal. A timely filed appeal shall be processed and considered by the Building Official in accordance with the provisions of Chapter 20.100 of the Mill Valley Municipal Code.

(Ord. 1367, 3/16/2026)