[f. LAG sb.2] trans. To cover (a boiler, etc.) with wooden ‘lags,’ strips of felt, etc.
1887. J. A. Ewing, in Encycl. Brit., XXII. 488/1. The loss of efficiency due to this cause will therefore be greater in an unprotected cylinder than in one which is well lagged or covered with non-conducting material.
1888. in Sheffield Gloss.
1891. Labour Commission, Gloss., Lagging a boiler, covering a boiler in a steamship with some material to keep in the heat.
1898. Dublin Rev., April, 423. Lagged outside with layers of felt two centimetres thick.
