In November of 2018 the National Fire Chiefs Council issued a document that simplified the minimum requirements for Fire Investigation. The Competency framework defined a two-tier system, briefly described as:

Tier 1 Fire Scene Investigations. Routine Fire Investigations usually undertaken to provide information required for the National Incident Recording system. Normally carried out by crew and watch managers who should receive a level of fire investigation awareness training which enables them to accurately complete the IRS. These personnel should be trained and competent to a level equivalent to meet all of the Skills for Justice level 2 Introduction to Fire Investigation Assessment criteria.

Tier 2 Fire Scene Investigations defined as complex fire and or explosion incidents where the origin and Cause is not easily established. The document also outlined the process for more serious fires stating that these should be investigated by a competent Tier 2 Investigator with specific training to undertake a more detailed investigation than a tier 1. Tier 2 investigators should be trained and competent to meet the SFJ level 5 certificate in Fire Investigation and be working to the standards prescribed in 2The Code of Practice for Fire Investigators within the Criminal Justice System.

An updated and more in-depth document was published in July 2021 aiming to drive improvement and consistency in service delivery and to help progress towards BS/EN ISO 17020. This revised framework document will assist FRS in demonstrating how they assure the competence of their fire investigation staff.

Tier 1 standards of training were outlined as the criteria identified within the SFJ level 2. Tier 2 Investigations to be carried out by those personnel demonstrating the essential knowledge and skills equivalent to a level 5 qualification. Working to the Code of Practice for Fire Investigators of Fires and Explosions for the Justice Systems in the UK, The forensic Regulators Code of Practice and BS/EN ISO 17020 where applicable. These Investigators must meet all specified elements and be able to demonstrate competence in their role against the National Occupational Standards. This competence must routinely be reassessed at defined intervals to ensure it is maintained and up to date. The document fully outlines the route to achieve the standard and competence within it.