🔍 Key Concepts

• Function of firebrick (refractory) in boiler furnaces • Heat transfer and protection of water wall / generating tubes • Protection of furnace structure and casing from high temperature

💭 Think About

• Think about where firebrick (refractory) is physically located in a water tube boiler and what parts of the boiler it is in direct contact with. • Ask yourself: what components in the furnace actually need shielding from direct flame and high radiant heat? Just the tubes, just the casing, or more than one thing? • Consider whether firebrick’s role is mainly structural, thermal protection, or both, and which of the listed statements match that purpose.

✅ Before You Answer

• Verify what refractory/firebrick is designed to do: insulate, reflect heat, and protect metal components. • Check which metal parts would be damaged first by direct flame impingement and very high furnace temperature. • Confirm whether the inner casing of the furnace is directly exposed to the flame without firebrick in place.