Expanded Shale, Clay, and Slate (ESCS) Lightweight Aggregates

Declaration details

Manufacturer

Expanded Shale, Clay and Slate Institute

Program operator

Smart EPD

Declaration number

SmartEPD-2026-155-1066-01

Date of issue

September 23, 2026

Valid until

September 23, 2031

Product category rules (PCR)

UL Part B: Expanded Shale, Clay, Slate, and Lightweight Aggregate (version 1)

Standard

ISO 14025:2006 and ISO 21930:2017

Declared unit

1 m3 of manufactured ESCS lightweight aggregate of product equivalent to 1.308 cubic yards

System boundary

Cradle to gate (A1 - A3)

Product specificity

Product Average

Manufacturing specificity

Industry Average

Product category

Aggregates

Product service life

100 years

Verifier

Sarah Curpen

LCA software

In-house LCA calculation tool N/A

Program instructions

Smart EPD General Program Instructions v.2.0, March 2025

Life cycle assessment results

Results per 1 m3 of manufactured ESCS lightweight aggregate of product equivalent to 1.308 cubic yards.

Environmental Impact Assessment Results

Resource Use Indicators

Waste and Output Flow Indicators

ND = not declared. Life cycle modules: A1-A3 product stage, A4-A5 construction process, B use stage, C end of life, D benefits and loads beyond the system boundary.

Material composition

Hazardous substances

No regulated hazardous or dangerous substances are included in this product.

Product description

ESCS is a ceramic material produced by expanding and vitrifying select shale, clay, or slate minerals in a rotary kiln at temperatures over 1000°C (1830°F). The production and raw material selection processes are strictly controlled to ensure a uniform, high-quality, lightweight aggregate. The process produces a high-quality ceramic aggregate containing a uniformly distributed system of pores with a size range of approximately 5 to 300μm (0.2 to 12 mil), developed in a continuous, relatively crack-free, high-strength vitreous phase. The ceramic nature of the aggregate ensures that the product is inert, non-toxic, and highly resistant to degradation. Interior pores are essentially non-interconnected; a small fraction remains unfilled after years of immersion. The pores system is responsible for the low density, insulative, and absorptive characteristics of ESCS. ESCS lightweight aggregate is a type of coarse and fine aggregate that is used in the production of lightweight concrete products such as concrete, masonry, backfill, pavement, soil amendments, and filter materials.

Interpretation

The A1-A3 results for the ESCS product show that the production stage A3 is the dominant contributor to most environmental impact categories. This is primarily due to fuel combustion for the high‑temperature rotary kiln process, and electricity use for drying, crushing, screening, and material handling. Transport to the construction site (A4) contributes a smaller share of impacts, mainly driven by diesel fuel use in heavy‑duty trucks.

Potential benefits beyond the system boundary (Module D) may occur when ESCS‑containing materials are recovered and used to replace virgin aggregate in future applications.

The results should be interpreted with consideration of the underlying assumptions, including scenario-based transport distances, regionally specific electricity mixes, typical end‑of‑life pathways, and closed‑loop internal recycling during manufacturing. Primary data quality for A1–A3 is high, and secondary datasets are temporally, geographically, and technologically representative for North American conditions. No data gaps are expected to materially influence the results.

The indicators presented are relative expressions of potential environmental impacts and do not represent actual environmental performance, risk, or exceedance of thresholds. Environmental improvements are most effectively achieved through optimizing kiln fuel use, improving energy efficiency, and increasing recovery and reuse of ESCS at end‑of‑life.