Understanding Timber Fire Treatment: Charring

The question describes a specific method of treating timber using fire. When timber is subjected to burning over a defined surface depth, typically around 15 mm, this process is aimed at surface modification or preservation.

Identifying the Charring Process

The process described, where timber is burnt to a depth of about 15 mm, is specifically known as charring. This technique involves exposing the wood surface to flame, creating a protective carbon layer.

Distinguishing from Other Treatments

Other timber treatment processes involve different methods:

• Rueping Process: Involves impregnating timber with preservatives under pressure after an initial vacuum.
• Bethel Process: A high-pressure treatment, often using creosote, to force preservatives deep into the wood.
• Boucherie Process: Uses the wood's natural sap flow to introduce preservatives, typically for poles and posts.

Charring differs significantly as it relies on controlled burning of the surface rather than chemical impregnation.

Conclusion on Charring

Therefore, burning timber over a depth of approximately 15 mm is identified as the charring process.