Pilkington Glass is to mothball one of two floatlines at its Cowley Hill site in St Helens, UK.
The closure will result in the loss of 140 jobs. The reason given by the company is the lack of demand for flat glass due to a continuing downturn in the construction sector.
The company plans to close the CH2 float line in November 2013. Off-line coating, silvering, laminating and warehousing operations will continue on the site.
The company, which employs 2,500 staff across the UK, said it decided to close the floatline at the Cowley Hill site after making "huge losses".
The firm has produced glass at the factory since 1871.
It will continue to manufacture float glass at its larger production line at Greengate in St Helens, and other activity including laminating and silvering will continue at Cowley Hill.
The company has said it is in discussions over compulsory and voluntary redundancies with employees and their representatives.
It is owned by Japan-based firm NSG, which in February cut 3,500 jobs globally.