The use of a membrane or water-cooled walls has reduced the use of __________ in modern water tube boilers.
A ) refractory
B ) insulation
C ) cladding
D ) castables
Answer: D
The use of a membrane or water-cooled walls has reduced the use of __________ in modern water tube boilers.
A ) refractory
B ) insulation
C ) cladding
D ) castables
Answer: D