​Where

• s = lifecycle scope, such as A1–A3 or A1–A5 or A1-C etc;

• X = acoustic descriptor, such as Rw, Rw+C, or Rw+Ctr;

• T = reference study period in years, where time-dependent lifecycle stages are included.

   

The result is interpreted as follows:

• ACER < 1: lower GWP than that of the acoustic rating equivalent concrete reference;

• ACER = 1: equal GWP;

• ACER > 1: higher GWP than that of the acoustic rating equivalent concrete reference.

ACER Standard Reference Concrete is a fixed conventional benchmark comprising 1 m² of homogeneous, monolithic and unreinforced concrete of variable thickness.

The proposed reference is based on the Mineral Products Association UK sector Environmental Product Declaration for C28/35 CEM II/C-M (S-L) + SR ready-mixed concrete, registration EPD-IES-0011234:002.

The carbon assumptions include:

• A1–A3 GWP-total: 176.0 kgCO₂e/m³;

• A1–A5 GWP-total: 183.3 kgCO₂e/m³;

• A1–C4 GWP-total: 178.9 kgCO₂e/m³ for 30 years; 176.7 kgCO₂e/m³ for 60 years; 174.5 kgCO₂e/m³ for 100 years

• A4: 10 km delivery by Euro 6 concrete mixer truck;

• A5: pumped placement, 2.24 kWh/m³ installation energy, 44.78 litres/m³ water and 1.5% construction wastage.​