Editing Firebox (steam engine) (section)

===Combustion chamber===

[[File:Hinterkessel.jpg|thumb|'''Combustion chamber''' of a steam locomotive firebox, extending forwards (leftwards) of the main firebox, into the boiler barrel]]

Some fireboxes were equipped with a so-called [[combustion chamber]], this is a distinct component from the firebox and tubes - a large single extension of the firebox space, into the boiler barrel, and above the brick arch and separated from the grate and the fire bed, this placed additional space between the fire and the rear fire tube/flue sheet. 

This allowed more complete combustion (reducing fuel wastage) and increased firebox surface area for greater heat-transfer, these  factors Improved both boiler efficiency and fuel economy.  The improved combustion (which reduces carbon-soot ejection) reduced the carry over of ash and soot into the fire-tubes and smoke box, reducing the frequency of cleaning required.  Soot buildup and scale buildup (on the water side) severely reduce heat transfer through the fire tubes/flues, reducing steam generation and boiler efficiency. 

Buildup of soot and scale can also lead to overheating and subsequent tube failure if not cleaned properly to remove soot (with water, compressed air and cleaning rods) and scale with boiler washouts and [[Water_treatment#Boiler_water_treatment|water treatment]] e.g. [[Boiler_feedwater#Locomotive boilers|Porta Treatment]] (minimizes and virtually prevents scale buildup) is named after the Argentine locomotive engineer [[Livio Dante Porta]], who invented it.