Should I specify a high percentage of recycled material?


Should I specify a high percentage of recycled material?

Recycling is good for the planet because it reduces waste and conserves (or substitutes) primary resources, furthermore recycling generally saves energy and reduces carbon emissions.

Specifying a high recycled content is a good driver for products where the aim is to encourage and establish a market for recycled materials that are otherwise limited, uneconomic or immature. This is not the case for steel however, which is already highly recycled (> 95% in the case of structural steel). Specifying steel with a high recycled content drives no positive climate impact at a global level, can have adverse consequences within the broader sustainability context and create market distortions.

It should be remembered that both major steel production routes use scrap. The primary or Blast Furnace-Basic Oxygen Furnace (BF-BOF) route up to 30% recycled content and the secondary Electric Arc Furnace (EAF) route 100%.

Specifying a high recycled content can be beneficial for some products however that is not the case for metals that are already highly recycled. Indeed, specifying steel with a high recycled content can have adverse consequences within the broader sustainability context.

In our daily lives we are all encouraged to recycle more. Recycling is good for the planet because it reduces waste and conserves (or substitutes) primary resources, furthermore recycling generally saves energy and carbon emissions.

But how should we measure and incentivise recycling? The answer to this is more complicated than the simple ‘recycling is good’ and ‘recycle more’ messages and needs to be understood by specifiers of construction products if unsustainable and unintended consequences are to be avoided.

There are two main ways of measuring recycling, recycled content and end-of-life recycling rate:

  • Recycled content is defined in ISO 14021 [1] and is a measure of how much recycled content (pre- and post-consumer) is used in the production of a new product,
  • End-of-life recycling rate is a measure that compares the actual amount of materials recycled with the amount of metals theoretically available at the end of the life of a product. In the context of construction, this is the proportion of demolition arisings that are recycled.

Specifying a high recycled content is a good driver for products where the aim is to encourage and establish a market for recycled materials that are otherwise limited, uneconomic or immature.

For example, the recycled content approach may be a useful metric/driver for a material that would otherwise be incinerated or landfilled as waste. Specifying a recycled content for products incorporating these materials, can divert them from incineration and landfill to recycling and reuse. Importantly, this is not the case for metals − as discussed below, metal recycling is economical and the metals recycling market is extensive and mature.

The application of the recycled content approach may create market distortions and environmental inefficiencies. If a designer specifies high recycled content in a well-meaning effort to reduce environmental impacts, it may stimulate the market to direct recycled feedstock towards designated products and away from production where recycling is most economical. For metals, where there is a limited supply of recycled feedstocks, market stimulation is ineffective and may result in inefficient processing and unnecessary transportation. See the declaration on recycling principles by the metals industry [2].

Global steel production
Global consumption of steel products continues to rise, mainly as a consequence of industrialisation in developing economies and particularly, in recent years, growth in China. For example, the World average per capita consumption of crude steel in 2019 was 229 kg. By comparison, the EU-28 average consumption is 310 kg/capita, UK consumption was 151 kg/capita and average consumption in Africa was just 28 kg/capita [3].

Global demand for new steel exceeds the supply of scrap steel by a factor of around two and therefore, to meet this increasing demand, new steel has to be produced from primary sources by the BF-BOF production route. Supplies of ferrous scrap are finite and exclusively specifying 100% recycled steel, will result in an increased demand for scrap that cannot be met and is not only unsustainable but may also drive up scrap prices.

Within the global context, there is no point specifying 100% recycled steel (in preference to BF-BOF steel) as all this will mean is that BF-BOF steel will be required to substitute EAF production to meet the excess global demand elsewhere. In addition, specifying imported 100% recycled steel in the UK, adds further transportation impacts.

The corollary of this is that on a global scale and while global demand for new steel exceeds the global supply of scrap, it is the end-of-life recycling rates achieved (not the recycled content) that is important for sustainable development.

This is not just the view of the metals industries. The following are extracts from other, independent sources.

WRAP undertook a number of studies promoting the use and specification of recycled content for construction products. However, for metals, WRAP concluded [5]:

For recycled content within the metals industry, where recycling is already optimised (where over 90% of waste arising is recycled or reused), an industry average for each product type, e.g. aluminium sheet or steel sections, should be declared, rather than on a site-by-site or company-by-company basis. If, for example, steel sections available globally to the UK market have 60% recycled content on average, then the steel industry could all use that figure as the recycled content of sections.

In her article [6] Kirsten Henson states:

Rather than insisting on high recycled content in structural steel, which ultimately drives no positive climate impact on a global scale (due to the fact that the majority of steel is already captured at end-of-life and recycled) and potentially contributes to the further decline of the UK steel industry, architects and building owners must seek innovative ways of re-using existing structures and engineers must use ingenuity to deliver the most materially efficient design solutions.

The ICE database V2.0 [7] includes an excellent, detailed treatise on how to account for the recycling of metals in embodied carbon assessments. The ICE authors share the views of the metals industry about market possible distortions that can result from specifying a high recycled content for steel. Consequently, the ICE database, which is ‘cradle-to-gate’ (Modules A1 – A3) only, recommends the implementation of an effective average recycled content for steel products and states:

To implement this method effectively the same recycled content must be modelled for all different forms of (carbon) steel (e.g. rebar, sheet or section). Technological and economic factors often dictate where scrap materials are directed. The fact that a certain type of steel is almost exclusively manufactured from primary feedstock (iron ore) or secondary feedstock (scrap steel) becomes irrelevant. For example, steel rebar is often manufactured in an electric arc furnace (EAF) and therefore often has a recycled content of 100%. Conversely steel sheet is typically derived from a primary production route. An increase in the demand and production of steel rebar will not result in an increase in the global average recycled content for worldwide steel. Likewise, an increase in the demand and production of steel sheet will not reduce the global average recycled content. Scrap steel remains a valuable commodity and will be consumed regardless of the demand for certain types of steel. Consequently, changes in the demand of certain forms of steel (rebar, sheet or section) have no capacity to increase the global average recycled content. The consequences of this are that although rebar is normally made from recycled steel and sheet is typically made from virgin steel both materials are given an ‘effective market average recycled content’ within the ICE database.