eToolLCD follows the EN15978 standard for calculating recycling burdens and benefits. What this means in simple terms is:
If the building designer is hoping to understand the net benefits associated with recycled content in buildings products used for construction and refurbishment, they should report Modules A-C inclusive. In other words, reporting Modules A-C rewards the use of recycled content in new products.
If the building designer is hoping to understand the net benefits associated with recycling rates in the waste streams from refurbishment and demolition at the end of a products life they should report Modules A-D inclusive. In other words, reporting Modules A-D rewards design for deconstruction (high recycling rates in the waste stream).
The methodology that drive this approach is that only the net outflow of a product is considered in Module D. So if a material used in the buildings has a very high recycled content (when new) but a lower recycling recovery rate (in the waste stream) there will be negative net flow of material for secondary use from the system and a burden will be applied in Module D. If on the other hand a product has a low recycled content and a high recovery rate there will be a large positive net outflow of material for secondary use and a benefit will be applied in Module D.
Closed Loop Recycling
The figure below demonstrates how impact calculations are made for the different life cycle phases. In this example, the material is made up of 40% recycled content and 60% primary production content. The impacts associated with primary production are 10units. The impacts associated with secondary production are 2 units. Based on these parameters, the calculation for Module A1-A3 is:
A1-A3 = Primary Impact x Primary Content (%) + Secondary Impact x Secondary Content (%)
A1-A3 = 10 x 0.6 + 2 x 0.4
A1-A3 = 6.8
At the end of the building life, 10% of the material is lost to landfill due to collection losses, corrosion, materials embedded within waste etc. 90% of the material hence flows through to secondary production. In EN15978, a benefit of only 50% of the total material input (not 90%) is claimed in Module D because of the original material contained 40% recycled content. So the net benefit calculated in module D is:
D = (Recycling Rate – Secondary Content) x (Secondary Impact – Primary Impact)
D = (0.9 – 0.4) x (2 – 10)
D = 4
Although this method means that the values of A1-3 and D will change depending on both recycled content and end of life recycling rate, the net impact (A1-3 + D) is entirely dependent on end of life recycling rate. If a study excludes reporting of Module D, the recycling allocation approach matches that of a recycled content allocation (100%,0%) and if Module D is included, it matches that of an end of life recycling rate allocation (0%,100%). In other words, the design for recovery and reuse methodology is supported in determining net impacts due to recycled content and recycling rates. A similar example is given in the Product Category Rules for Aluminium Products (European Aluminium Association 2013).
Open Loop Recycling
Materials that are recovered for downstream use in other materials re-entering the economy need special treatment to differentiate where impacts and benefits will be allocated. Examples include:
- Brick waste that is crushed and used in road base
- Concrete waste that is crushed and used in road base
- Plastics that are down cycled into less pure products
- Glass that is crushed and used as aggregate
These materials do offset the use of primary materials and hence can have net benefits on the environment where recovery makes sense. As the materials they are replacing often have very low primary impacts anyway (eg road base), the benefits can be marginal and may depend largely on transportation distances.
Economic allocation is used to differentiate where benefits and loads should be accounted for. If a material is a genuine waste at the end of the building life cycle (negative value or zero value) then at this point no benefits can be claimed for this building, and the next building (recovered materials used in place of primary materials) will claim the benefit in modules A1-3. If the material has value at the end of the building life, the net benefits of recovery and primary material offsetting can be claimed in module D.