Atmosphere volume requirements

It depends on

1. Type and size of furnace
2. Environment and presence of draft.
3. The nature and size of work pieces.
4. Metallurgical process involved.
5. Presence or absence of curtains  at entrance and exit.

Atmospheric sensors

It is important to measure the concentration of various components of the atmosphere during the treatment in the furnace. The constituents of atmosphere are  and hydrocarbon gases such as CH₄. The main objective of furnace atmosphere is to prevent decarburization, hydrogen embrittlement, oxidation, surface blueing and soot formation.

ORSAT analysis can be used to determine the composition of  and . ORSAT  analysis is described in lecture 10.

Among other techniques gas chromatography, thermal conductivity, oxygen sensors, dew point are also used. Details about the sensors can be obtained in references given at the end of the lecture.
 
References:

Y.V. Deshmukh: industrial heating. 2004.
Furnace atmospheres and carbon control: ASM Committee on furnace atmospheres