24 24 16-18 14 14 16 8½ by 8½ 10 28 24 16-18 14 14 16 8½ by 8½ 10 24 28 16-18 14 14 20 8½ by 8½ 10 30 28 16-18 16 14 20 8½ by 13 10 36 28 16-18 22 14 20 8½ by 13 12 42 28 16-18 28 14 20 8½ by 18 12 36 32 18-20 20 14 24 8½ by 18 12 42 32 18-20 26 14 24 13 by 11 12 48 32 18-20 32 11 24 13 by 13 15 42 36 18-20 26 11 28 13 by 13 15 48 36 18-20 32 14 28 13 by 18 15 54 36 18-20 38 14 28 13 by 18 15 60 36 18-20 44 14 28 13 by 18 15 42 40 20-22 24 17 29 13 by 13 15 48 40 20-22 30 17 29 13 by 18 15 54 40 20-22 36 17 29 13 by 18 15 60 40 20-22 42 17 29 18 by 18 18 66 40 20-22 48 17 29 18 by 13 18 72 40 22-28 51 17 29 18 by 18 18 [Illustration: Figure 33.--In regions where natural gas is plentiful and in cities, fireplaces of this type, burning gas with a flickering flame, are frequently used as an auxiliary to the main heating plant. Some types have imitation logs of metal perforated for gas jets.] Footings Footings for chimneys with fireplaces should be provided as described on page 7; for chimneys without fireplaces, the footings should rest on good firm soil. [Illustration: Figure 34.--A typical fireplace, illustrating practical details of construction. An alternate method of supporting the hearth is shown in the lower right-hand corner. The various letters refer to specific features discussed in the text.] Hearth The hearth should be about flush with the floor, for sweepings may then be brushed into the fireplace. When there is a basement, an ash dump located in the hearth near the back of the fireplace is convenient. The dump consists of a metal frame about 5 by 8 inches in size, with a plate, generally pivoted, through which ashes can be dropped into a pit below (fig. 35). [Illustration: Figure 35.--The ash-pit should be of tight masonry and should be provided with a tightly fitting iron clean-out door and frame about 10 by 12 inches in size. A clean-out for the furnace flue as shown is sometimes provided.]