The specification was prepared and published by the British Standards Institution (BSI) and built on the previous 'Standards for Compost' scheme.

It improves confidence in composted materials among end-users, specifiers and blenders, and helps producers differentiate products that are safe, reliable and of high performance. BSI PAS 100 is the specification that composted materials must meet in order to achieve the independently verified Compost Certification Scheme.

BSI PAS 100 was developed following extensive consultation across the compost industry. It only covers biodegradable materials that have been kept separate from non-biodegradables, and applies to composted materials produced at centralised, on-farm and community composting facilities. It does not extend to end products of home composting for self-use.

The specification was updated in 2011 following a period of intensive stakeholder review and consultation, building on its predecessor by including a number of improvements and efficiencies.

Key improvements included:

  • New upper limits for some test parameters
  • A new test method for E.Coli. 
  • The updated BSI PAS 100 does not allow the composting of sewage sludge or its derivatives
  • Allows the addition of digestates from anaerobic and aerobic digestion processes
  • References to new legislation, guidelines and scientific reports
  • Re-formatted to make it easier to use

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Download conditions

  • The Publicly Available Specifications (PAS) which are available for download from this website are made available to the public with the permission of the British Standards Institution (BSI) under licence. Copyright in all BSI publications is owned by the BSI. Please respect this copyright.
  • The PAS are available to download on the condition that they are not reproduced, duplicated, copied, sold, resold or exploited for any commercial purposes.
  • Downloads from this website are subject to WRAP’s Terms and Conditions.

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