Data Source Quality

Data Quality Assessment

Data quality/variability requirements, as specified in the PCR, are applied. This section describes the achieved data quality relative to the ISO 14044:2006 requirements. Data quality is judged based on its precision (measured, calculated or estimated), completeness (e.g., unreported emissions), consistency (degree of uniformity of the methodology applied within a study serving as a data source) and representativeness (geographical, temporal, and technological).

Precision: Through measurement and calculation, the manufacturers collected and provided primary data on their annual production. For accuracy, the LCA practitioner and 3rd Party Verifier validated the plant gate-to-gate data.

Completeness: All relevant specific processes, including inputs (raw materials, energy and ancillary materials) and outputs (emissions and production volume) were considered and modeled to represent the specified and declared products. The relevant background materials and processes were taken from ecoinvent v3.4 LCI databases where relatively recent Canadian-specific electricity inputs were utilized.

Consistency: To ensure consistency, the LCI modeling of the production weighted input and output LCI data for the declared products used the same modeling structure across the respective product systems, which consisted of raw material inputs and ancillary material, energy flows, water resource inputs, product and co-products outputs, returned and recovered concrete materials, emissions to air, water and soil, and waste recycling and treatment. The same background LCI datasets the ecoinvent v3.4 database were used across all product systems. Crosschecks concerning the plausibility of mass and energy flows were continuously conducted. The LCA team conducted mass and energy balances at the plant and selected process level to maintain a high level of consistency.

Reproducibility: Internal reproducibility is possible since the data and the models are stored and available in a machine readable project file for all foreground and background processes, and in P3 Optima’s proprietary concrete LCA calculator* for all production facility and mix-specific calculations. A considerable level of transparency is provided throughout the LCA report as the specifications and material quantity make-up for the declared products are presented and key primary and secondary LCI data sources are summarized. The provision of more detailed data to allow full external reproducibility was not possible due to reasons of confidentiality.

*P3 Optima has developed a proprietary tool that allows the calculation of PCR-compliant LCA results for ready-mixed concrete product mix designs. The tool auto-calculates results by scaling base-unit technosphere inputs (i.e. 1 kg portland cement, 1 kWh electricity, etc.) to replicate the reference flow conversions that take place in any typical LCA software like openLCA or SimaPro. The tool was tested against several LCAs performed in openLCA and the tool generated identical results to those realized in openLCA across every impact category and inventory metric (where comparisons could be readily made).

Representativeness: The representativeness of the data is summarized as follows.

• Time related coverage of the manufacturing processes’ primary collected data from to .
• Upstream (background) LCI data was either the PCR specified default or more appropriate LCI datasets as found in the Canadian-adjusted ecoinvent v3.4 database, 2017.
• Geographical coverage for the cement and concrete plant operations is Canada; other upstream and background processes are based on US, North American, or global average data and adjusted to regional electricity mixes when relevant.
• Technological coverage is typical or average – specific to the participating facilities for all primary data.