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Bricks and brickwork
Published in Arthur Lyons, Materials for Architects and Builders, 2019
Introduced in 1858, the Hoffman kiln is a continuous kiln in which the fire is transferred around a series of chambers that can be interconnected by the opening of dampers. There may be 12, 16 or 24 chambers, although 16 is usual. The chambers are filled with typically 100,000 green bricks. The chambers in front of the fire, as it moves around, are preheated, then firing takes place (960–1000°C), followed by cooling, unloading and resetting of the next load. The sequence moves on one chamber per day, with three days of burning. The usual fuel is natural gas, although low-grade coal and landfill methane are used by some manufacturers. Hoffmann kilns are being phased out of production in the UK.
Materials and components for masonry
Published in Peter Domone, John Illston, Construction Materials, 2018
The Hoffman kiln is a multi-chamber kiln in which the bricks remain stationary and the fire moves. It is mainly used for the manufacture of Flettons. In the classic form it consists of a row of chambers built of firebricks in the form of short tunnels or arches. In the most efficient form the tunnels form a circle or oval shape and are connected together and to a large central chimney by a complex arrangement of ducts. A single ‘fire’ runs round the circle and at any one time one chamber will be being loaded or ‘set’ ahead of the fire and one will be being unloaded behind the fire. The bricks are stacked in the kiln in groups of pillars termed ‘blades’, which leaves lots of spaces between units to enable the gases to circulate freely. Chambers immediately in front of the fire will be heating up using the exhaust gases from the hottest chamber, and those further ahead will be being dried or warmed by gases from chambers behind the fire that are cooling down.
Materials and components for masonry
Published in Marios Soutsos, Peter Domone, Construction Materials, 2017
The Hoffman kiln is a multi-chamber kiln in which the bricks remain stationary and the fire moves. It is mainly used for manufacture of Flettons. In the classic form, it consists of a row of chambers built of firebricks in the form of short tunnels or arches. In the most efficient form, the tunnels form a circle or oval shape and are connected together and to a large central chimney by a complex arrangement of ducts. A single ‘fire’ runs round the circle and at any one time one chamber will be being loaded or ‘set’ ahead of the fire and one will be being unloaded behind the fire. The bricks are stacked in the kiln in groups of pillars termed ‘blades’, which leaves lots of spaces between units to enable the gases to circulate freely. Chambers immediately in front of the fire will be heating up using the exhaust gases from the hottest chamber, and those further ahead will be being dried or warmed by gases from chambers behind the fire that are cooling down.
Structural Design Innovation and Building Technology Progress Represented by a Hybrid Strategy: Case Study of the “Wartime Architecture” in China’s Rear Area during World War II
Published in International Journal of Architectural Heritage, 2020
There is, of course, a predisposing factor that needs to be made clear: the “wartime architecture” must be constructed as much as possible in combination with plastered bamboo-fence walls and less with bricks. The technical logic was due to the shortage of sintered bricks in Chongqing and in the whole central and western regions at that time, especially the Hoffmann kiln. The kiln was used for a large production of machine-made clay bricks and was far from common in this area. However, the cost could be effectively reduced by adopting plastered bamboo-fence walls instead of masonry walls of bricks (Figure 12). For this reason, only bathrooms of the Baixi Campus of the National Central University used brick walls, and the rest all used plastered bamboo-fence walls. However, the plastered bamboo-fence wall was originally developed as a simple technical measure for column and tie construction, so it was not convenient to combine it with the western roof frame, especially the truss supported at both ends. As there were few or even no vertical landing bars, if the plastered bamboo-fence wall was to be used, the construction column and wall keel had to be set up separately (Figure 13), which increased the workload of design and construction, and hindered the reduction of labor and material costs. The advantage of the column and tie construction was that the center distance between the columns of the naturally formed wooden grid was generally 0.8–1.5 m, which can be combined with the plastered bamboo-fence wall, and was also a common practice of local craftsmen. Therefore, such a reasonable logic based on the concept of hybrid design was formed. In partition walls, gable column and tie construction was used in order to strengthen the buildability; the roof truss was used in the upper part of the larger space to reduce or even cancel the need for columns and provide high spatial compatibility.