LCA threshold

Unblock an exceeded LCA threshold (collective housing)

ARKEMEP optimises the life cycle assessment before filing to bring the carbon indicator back below the RE2020 threshold. This is a design engineering assignment.

Getting back below the carbon threshold before filing

When the Ic_construction indicator of a collective-housing project exceeds the RE2020 threshold, the permit filing is at risk. The lever is upstream: material and construction-method choices, per-package LCA calculation, design trade-offs. ARKEMEP conducts this optimisation as an engineering firm, before the file is blocked.

It is a design engineering assignment, not coupled to any certification. The earlier it starts in the programme, the more room there is to bring the indicator below the threshold without inflating the operation.

FAQ

Frequently asked questions

The optimisation focuses on material choices, per-package LCA calculation and design trade-offs, upstream of the filing. ARKEMEP conducts this engineering; no certification is coupled to it.
Thresholds tighten through successive regulatory steps (2025, 2028, 2031). ARKEMEP calibrates the design LCA below the applicable threshold to absorb construction-phase variation.

The situation

The threshold is missed, the permit is filed, the clock is running.

The most frequent version of this problem: a collective housing scheme reaches the carbon calculation late, exceeds the applicable threshold, and the structural design is already fixed. At that point the obvious answers, change the structure, change the envelope, are the expensive ones, and they restart the design.

The less obvious answers are usually available and are found in the calculation rather than in the building. Environmental product declarations for the actual products specified, rather than default values, frequently move the result by more than a material substitution would.

Method

Interrogate the model before rebuilding the project.

A carbon model built on default data is deliberately conservative: the regulation penalises the absence of information. Replacing defaults with manufacturer-specific declarations, verifying quantities against the actual bill of materials, and checking the allocation of shared elements typically recovers a meaningful margin, without changing a single design decision.

Where that is not enough, targeted substitutions ranked by carbon-per-euro give the project a shortlist rather than a redesign. The point is to know which lever is worth pulling, which requires the model to be interrogated first.

Going further

Related pages.

This question connects to these pages.

Optimise a blocked LCA

ARKEMEP, LCA and thermal engineering under one roof.

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