Description
The Bacharach 21-0018 Smoke Scale is a printed reference card used to assess the density of combustion byproducts collected on a filter paper sample during a flue gas analysis test. It provides a graduated visual scale numbered from zero to nine, where each increment represents an increasing level of particulate concentration. Within HVAC systems, this scale is used during boiler and furnace tune-ups to evaluate burner combustion quality, where a higher smoke number indicates incomplete fuel burning that requires burner adjustment, nozzle replacement, or air-to-fuel ratio correction.
