Retrotec USACE - Manual (Page 181)

Appendix D D51
D.4.1.12 Damaged or Missing Refractory (Ineffi ciency)
Figure D83. Damage to housing (left) of boiler (right).
Figure D84. Inside of boiler, showing water
tubes and refractory.
Refractory or masonry blocks known as bricks are used as the inner lining of
the combustion chamber. They protect boiler components from high tempera-
tures and aid in the insulation of the boiler’s walls and roof. Defi ciencies in
the refractory can result in damaging of the boiler and excessive heat losses
(Figure D83). The internal refractory should be inspected on a yearly basis
when the boiler is undergoing inspection and cleaning (Figure D84).
D.4.1.13 Combustible Gases in the Flue Exhaust (Ineffi ciency)
Figure D85. Combustion gas monitors located
in boiler breeching to analyze products of
combustion.
If there is a presence of high levels of carbon monoxide, unburned natural gas,
or high levels of soot in the combustion gases, inadequate oxygen is present at
the burner for proper combustion. Poor boiler effi ciency will be the result. If
the concentration of combustible gases is too high, an explosive mixture could