Closing the damper won't do it, and closing off the firebox opening won't either.
From the charlotteobserver.com
I like the tepee method in my fireplace on the base of the firebox without a grate.
From the freep.com
Much of that work was completed, and the boiler and firebox remain in Pennsylvania.
From the newsday.com
The refinery gate guard ran to firebox 547 at the corner of 57th and Butler.
From the post-gazette.com
So I've decided to squeeze the tree on the raised hearth to the left of the firebox.
From the courier-journal.com
The restored steam train was retired again in 1999 after firebox problems.
From the nznewsuk.co.uk
No sensible heating contractor would caulk a cracked firebox in a furnace.
From the dailyherald.com
High-heat resistant paint can be used to cover the firebox when updating a fireplace.
From the charlotteobserver.com
A mock firebox and coal tinder will encourage kids to shovel coal into a glowing firebox.
From the kentucky.com
More examples
A furnace (as on a steam locomotive) in which fuel is burned
The firebox or firepit is the part of the fireplace where fuel is combusted, in distinction to the hearth, chimney, mantel, overmantel and flue elements of the total fireplace system. The firebox normally sits on a masonry base at the floor level of the room. ...
A firebox is used in the manufacturing of moonshine. It is often fashioned from stones or bricks, to contain the flames while also concealing them, and to keep the still apparatus above the ground.
In a steam engine, the firebox is the area where the fuel is burned, producing heat to boil the water in the boiler. Most are somewhat box-shaped, hence the name.
The bottom of the grill that holds the fire or heat.
This is the place where the fire is built. It consists of 3 walls and a floor constructed of firebrick and refractory mortar. This is where the grate is placed.
The part of a fuel-burning kiln where fuel gases combust before contacting wares. Gas kilns need little if any firebox, while wood and oil kilns produce long hot flames which require a large firebox unless flame-flashing and ash-slagging (with wood) effects are sought.
Literally a box containing the fire. It is surrounded by water on the top and all sides. The bottom is a grate with an ash pan below that.
That portion of the solid fuel appliance where the fuel is located and where primary combustion occurs.