Details

The monument includes the standing and buried remains of a Hoffman Kiln,
situated in an industrial estate on Aizlewood Road, Sheffield.

In the 19th century production of bricks was limited by the time taken to
load, fire and unload the kilns that were then in use. These were known as
intermittent kilns which were fired individually as and when they were
required. The process was uneconomical as much of the fuel was consumed in
bringing the kiln up to firing heat. A technical breakthrough came with
the invention of the continuous kiln of which the first successful example
was built by the Austrian Fredrich Hoffman in 1857 and patented in 1858.

A Hoffman kiln is divided into bays which are loaded and fired in sequence
so that the fire burns continuously and efficiently, the flue gases being
directed into the required bay and for the required amount of time. The
green clay would be wheeled in on wooden barrows into the kiln bay, the
moulds would be stacked up and the access sealed for a week or so. The hot
flue gases would then be admitted for the required length of time.

The kiln on Aizlewood Road was built by the Sheffield Patent Brick Company
in 1879. It is rectangular in plan with rounded ends and is characteristic
of a design developed by Hoffman himself in 1870. The building is built of
brick and measures approximately 51m by 20m. It survives to roof height
although the chimney has been removed to accommodate the factory unit
which now sits above it. Externally it is clear that there were a number
of arched openings most of which are now blocked. Two of the openings have
been recut to provide modern access to the building. Internally small
arched openings representing bays are also evident at various points
around the kiln walls. The smoke flues, chamber flues, dampers and the
chimney are arranged in a linear pattern running north west to south east
down the centre of the building. The flue gases would have been directed
from this area to the relevant bay and the smoke expelled via the chimney.
The kilns firing chamber is basically `0'-shaped in plan with the central
flue system running down its centre. The electricity generator for the
factory unit above is housed in one of the central flue chambers.

The corrugated metal built factory unit above the kiln, the attached metal
stair cases which provide access to the first floor, the modern
ventilation flues attached to and penetrating the kiln and the adjoining
metal and breeze block storage units and tanks along the south western
side of the monument are excluded from the scheduling, although the ground
beneath all these features is included.

MAP EXTRACT
The site of the monument is shown on the attached map extract.

Source: Historic England

Reasons for Scheduling

The Hoffman kiln between Aizlewood Road and Cutts Terrace is a
particularly well-preserved example. Above ground it retains important
structural remains with architectural detail which contributes
significantly to the understanding of the physical development and
workings of the kiln. Below ground important archaeological deposits will
provide information relating to the use and technological development of
the kiln. Taken as a whole this information will add to our understanding
of the brick industry and its place within the wider industrial landscape.

Source: Historic England

Sources

Books and journals
Hague, G, 'The Yorkshire Architect' in The Brick Making Industry In Sheffield, , Vol. Jul/Aug, (1981), 38-39

Source: Historic England