Senior Architectural Systems has expanded its Environmental Product Declarations beyond curtain wall to include three PURe aluminum window and door systems—using a methodology that strips out glazing to expose the true carbon footprint of the aluminum itself. Here's why spec writers and embodied-carbon consultants should care.
A Different Way to Read an Aluminum EPD
UK fenestration system house Senior Architectural Systems has expanded its library of independently verified Environmental Product Declarations (EPDs), adding four new documents to a methodology that is quietly reshaping how architects and contractors read carbon data for aluminum fenestration.
Following the publication of the EPD for its SF52 mullion-drained curtain wall, Senior has released new declarations for its PURe Commercial Door, PURe Casement and PURe Tilt & Turn aluminum windows, plus the zone-drained version of its SF52 curtain wall system. That brings the total to five product-specific EPDs covering the company's most-specified commercial systems.
For spec writers working under tightening whole-life carbon reporting requirements—whether driven by the GLA in London, LETI benchmarks, or the embodied-carbon limits creeping into Part Z proposals—the methodology matters as much as the numbers.
Why the Glazing Is Missing on Purpose
The defining choice in Senior's EPDs is what they leave out. The data focuses solely on the aluminum system itself, with insulated glass units removed from the calculations. The company argues that including IGUs in an aluminum system EPD is misleading because the heavy weight of glass, combined with its relatively low carbon per kg, can make the overall figures for the aluminum system look lower than they really are after conversion to a per-square-meter declared unit.
It is also a more honest reflection of how the supply chain actually works. Glazing is typically not supplied by system houses—it is sourced separately by the fabricator or contractor, often with its own product-specific EPD. Bundling it into the aluminum EPD double-counts carbon at best and obscures specification decisions at worst.
The practical implication: when you compare Senior's per-m² GWP figure to a competitor's that includes glazing, you are not comparing like for like. Architects pursuing accurate whole-building life-cycle assessments need to add glazing separately—and Senior's approach makes that arithmetic cleaner.
What's Actually In the Numbers
The EPDs go further than typical aluminum declarations in the other direction—by pulling in components that are often excluded. Senior's documents include the environmental impact of profile extrusion and non-aluminum components such as thermal breaks, gaskets and fixings. These elements are often excluded from conventional EPDs, yet they can significantly influence the overall footprint of a façade system.
That matters for the PURe range in particular. The PURe Commercial Door, PURe Casement window and PURe Tilt & Turn window systems all feature Senior's patented expanded polyurethane thermal break, which delivers high thermal performance without compromising design flexibility. Polyurethane has a meaningful carbon contribution per kg, and earlier-generation EPDs that excluded it were understating the system footprint.
The EPDs also use non-linear scaling, with multiple system sizes verified and consolidated into single publications—an approach Senior and its verifier EPD Hub say is currently unmatched in the sector. For architects, that means a single document supports configuration-specific carbon math instead of forcing a one-size reference back-calculation.
Practical Implications for Spec Writers
- Recalibrate your benchmarks. If your office is comparing aluminum curtain wall EPDs, check whether glazing is included. The same product can look 20–40% "greener" on paper depending on whether IGUs are bundled in. Standardize on glazing-excluded figures before you draw conclusions.
- Add glazing separately. Senior's approach assumes you are sourcing IGU EPDs from your glass supplier—Saint-Gobain, Pilkington, Guardian, AGC and Vitro all publish them. Build your LCA model with the aluminum system, the glazing, and the spacer/edge seal accounted for as separate line items.
- Press for component-level data. Thermal breaks and gaskets can move the per-m² number more than spec writers realize. When evaluating systems, ask whether the EPD covers profile extrusion and non-aluminum components, not just primary aluminum billet.
- Match scaling to project geometry. Non-linear scaling means specifiers can model the actual mullion grid being designed, not a generic reference façade. Use it on projects where bay width and floor-to-floor heights deviate from typical reference dimensions.
The broader signal is that EPD methodology is maturing fast. As whole-life carbon limits move from voluntary frameworks into procurement requirements and—eventually—building regulations, the days of treating EPDs as marketing documents are ending. Senior's PURe and SF52 declarations are a useful template for what spec-ready carbon data should actually contain.