BSI PAS 100 - Compost specification

The Publicly Available Specification 100 (BSI PAS 100) for composted materials was sponsored by WRAP and developed in conjunction with the Association for Organics Recycling (AFOR).

Development of BSI PAS 100

The specification was prepared and published by the British Standards Institution (BSI) and built on the existing AFOR '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. AFOR has adopted BSI PAS 100 as the specification that composted materials must meet in order to achieve the independently verified AFOR certification and use of the logo.

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

Complete the form below to download BSI PAS 100

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