In Victorian England, gas build-up in underground sewers was often a problem for the city dwellers. Old sewers were not always laid on sufficient grade or on true line resulting in the accumulation of dangerous and highly inflammable methane gas that increased the chances of explosion. To prevent the build-up of stagnant gases, holes were poked into the sewer and free-standing vent pipes were installed to allow the foul gases to escape over the heads of pedestrians and the levels of adjacent homes. But some of these problematic sewers were located in areas where homes were multi-storied making vent pipes ineffective.
In the 1890s, Joseph Edmund Webb of Birmingham invented and patented a device called the “sewer gas destructor lamp” to deal with the problem of putrid sewer gases. These lamps looked and behaved like ordinary gas lamps that were once a common feature on streets around the United Kingdom and the rest of Europe as well. Webb’s idea was to vent methane gas up and out of the sewer mains through the lamp post to the burner at the top where it would be consumed by the flames. Webb expected the lamps to be fuelled entirely by sewer gas effectively turning a nuisance into functional street lights.
However, it was soon realized that the system didn’t work as expected —there was not enough methane to power the lights. The flame would die quickly and subsequent unburned methane release would create a nauseas condition in the area. Webb quickly modified his design so that the lamps burned town gas like ordinary gas lamps did, but they were still connected to the sewers below. The heat generated by the lamp head created an up draught which pulled gases from the sewer through lamp column to the 370 degree centigrade flame, where it burned together with the town gas. A single lamp was said to be capable of venting up to three quarters of a mile of sewer. The gas lamps not only removed methane but they also helped to sanitize the sewer air by burning dangerous microbes.
The sewer gas lamp turned out to be so effective that they were installed all around the UK in towns and cities including London, Sheffield, Winchester, Durham, Whitley Bay, Monkseaton and Blyth, Northumberland. The lamps remained lit all round the clock. The city of Sheffield, being a hilly area was more prone to gas pockets, and so had the highest number of sewer gas destructor lamps. They still have many of these lamps and some of them are still functioning.
London’s last remaining sewer gas destructor lamp on Carting Lane was knocked off by a reversing lorry some years ago. It is now replaced by a replica. Although an imitation, the lamp has earned Carting Lane the nickname of ‘Farting Lane’.
Sewer lamps became obsolete with the change in plumbing practice. Today, sewage gas is vented out above the roofs through the buildings’ plumbing system.
Sources: Historic England / Historic UK / Wikipedia / The History of Sanitary Sewers