gasometers

A gasometer, or gas holder, is a large vertical storage tank used to hold town gas (coal gas) produced for lighting and heating. The term refers to a family of vessels designed to store gas at near atmospheric pressure, achieved with a movable internal gas holder that rises and falls inside a larger water-filled shell.

Construction typically comprises an outer steel tank containing a shallow bath of water and, inside it, a buoyant gas holder (a metal bell) that can float or be supported by the water. Gas is stored above the water within the bell; as gas is added, the bell rises, displacing water; as gas is withdrawn, it sinks. The outer shell often carries calibrated scales to indicate the volume of gas, and valves connect the holder to the distribution network.

Operation buffers production and consumption in town gas systems. Gas produced in a works fills the holder; the outer tank maintains water levels and acts as a seal. The stored gas volume is read from the scales on the shell, and the gas is supplied to consumers as demand requires.

History and decline: Gasometers were widely built in the 19th and early 20th centuries to store coal gas for urban distribution. With the shift to natural gas and changes in storage technology, many were dismantled or repurposed in the late 20th century. Some remain as protected industrial heritage sites and features of regional landscapes.

Capacity and scale: Individual gasometers varied in size, with diameters typically tens of meters and heights up to several tens of meters. They were iconic features of city skylines in Europe and North America and are often preserved or adapted for modern uses in the present day.