TR19 standards explained — what each edition changed

TR19 has been published in multiple editions since 1998. The current edition relevant to commercial kitchens is TR19 Grease (2019), which is the standard your insurer references and your cleaning contractor should work to.

Edition history

• TR19 (1998): first publication. Covered general ventilation hygiene including kitchen extract. Now superseded.
• TR19 (2005): updated guide. Tighter cleanliness thresholds. Superseded.
• TR19 (2013): introduced wet film thickness as the measurement methodology. Tightened frequency requirements. Superseded for kitchen-specific work.
• TR19 Grease (2019): current. Separated kitchen extract requirements from general ventilation hygiene. This is what you want referenced on your certificate.

What "TR19 Grease (2019)" added

The 2019 edition was the first to fully separate kitchen-extract-specific guidance from general ventilation cleanliness. Key changes:

• Clarified the WFT measurement methodology and the 200μm threshold.
• Tightened access panel requirements for full system inspection.
• Specified certificate content requirements in more detail.
• Clarified frequency classification for atypical kitchen patterns (dark kitchens, 24-hour catering, event-only kitchens).

What this means for your certificate

If your certificate references "TR19 (2013)" or earlier, it is technically outdated. Ask your contractor to reissue the certificate against TR19 Grease (2019), or commission a new clean.

See our TR19 certificate page for current wording.