Holdfast Training Services Trial Blog

While we’re all sitting at home I thought I’d share this nugget from 2019 that made a little comeback in a lessons learned session we had before lock down. It is also an unexpected opportunity to use the word dumpling in an engineering context.

Back in June 2019 Keltbray were contracted to demolish two old gas holders in Sydenham. These gas holders are the large expanding “city gas” storage vessels that expand upward as gas is pumped in. The gas holders in question were of the “dumpling type” with a clay mound in the base centre of the gas holder (think the bottom of a champagne bottle). The gas holder is then partially filled with water to form an effective seal against the ground as gas is pumped in (see below). 

Dumpling type, two tier gas holder

As part of the dismantling sequence, the crown (lid) of the gas holder is removed, and the water and sludge is pumped out. On 12 June 2019, approximately three weeks after the pumping was completed on one of the holders, a crack through the dumpling was reported to WHP following heavy rainfall. However, the crack was first seen when the dumpling was first exposed; at the time, the crack did not alarm the site team and was considered superficial. The condition on 12 June, with the crack clearly visible, is shown below.

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