Frequently Asked Questions

  • What is IBA? 
    IBA or Incinerator Bottom Ash is a residue from Energy from Waste processes that transform household and commercial waste into electricity. IBA typically contains glass, ceramics, metals, clinker, masonry and ash
  • What is IBA Aggregate?
    The major output of processing IBA is a sustainable source of aggregate, which can be used in construction for a variety of applications, including subbase for roads, hardstanding’s and industrial buildings. During processing of IBA, ferrous and non-ferrous metals are recovered and sent to be smelted and brought back into use.
  • Is IBA and IBA Aggregate hazardous?
    IBA and IBA Aggregate are classified routinely as non-hazardous by using the ESA IBA sampling & testing protocol. WRC General Report (esauk.org)
  • Does IBA & IBAA help the environment?
    For every single tonne of IBA processed, approximately 530 black bags are diverted from UK landfills;
    – For every tonne of IBAA used in construction, approximately 1.13tonnes of primary / virgin aggregate remains in the ground.
    – Energy from Waste and IBA processing facilities are typically located in urban areas, this significantly reduces the CO2 footprint when compared to primary / virgin aggregates extracted from rurally located quarries, because of reduced haulage distances to the place of use.
  • Can I use IBA Aggregate anywhere?
    Although not hazardous, IBA Aggregate is currently still considered a waste and therefore requires a regulatory tool for its use. Whilst the EA and IBA processors continue to work towards a permanent permitting solution, the current regulatory tool for IBA Aggregate to be used in construction projects is set out in the EA`s Regulatory Position Statement 247 Using unbound incinerator bottom ash aggregate (IBAA) in construction activities: RPS 247 – GOV.UK (www.gov.uk)
  • Do I use less IBA Aggregate than primary aggregate in construction projects?
    IBA Aggregate has a typical compacted bulk density of 2.1 tonnes per cubic metre when compared with quarried limestone that typically has a compacted bulk density of 2.4 tonnes per cubic metre. This means that you broadly require 12% – 13% less IBA Aggregate for your projects.
  • Does IBA Aggregate meet material specifications?
    IBA Aggregate is in scope for the Specification for Highways Works (SHW) Series 800 ROAD PAVEMENTS — UNBOUND, CEMENT AND OTHER HYDRAULICALLY BOUND MIXTURES, where as a manufactured aggregate it is a permitted constituent for all unbound mixtures including Type 1 (clause 803) subbase, and Cement and Hydraulically Bound Mixtures (HBM). IBA Aggregate is also in scope for the Specification for Highways Works (SHW) Series 600 Earthworks, where it is a permitted constituent for use as capping or fill. IBAA can be specified using criteria in EN13242 – Aggregates for Unbound and Hydraulically Bound Mixtures and EN13285 – Unbound mixtures.
  • How long has IBA Aggregate been used in the UK as construction material?
    IBA Aggregate has been successfully used in the UK for over 20 years. Currently the UK uses approximately 3 million tonnes of IBA Aggregate each year in construction projects.


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