Seamus James Laverty, 58, of Deer Park Road in Toome, pleaded guilty to 16 counts of fraud by false representation at Antrim Crown Court.
Laverty sold ordinary glass as fire safety glass between 2010 and 2013 when he worked on the factory floor of Glassworks Ireland.
The fraud totalled £145,000.
The glass was sold to the construction industry and later used in buildings across Northern Ireland, the Republic of Ireland and England.
These include the Ulster Hospital, Strathearn School in east Belfast, Lisburn Road Methodist Church in Belfast, Magherafelt High School in County Londonderry, Carrickfergus Primary School in County Antrim, Tallaght Hospital in Dubin and Manchester University.
A whistleblower, who was a competitor of Laverty, became suspicious of his company's cheap tenders and acquired a sample of fire safety glass from Glassworks Ireland.
He discovered it was, in fact, ordinary laminate glass which had been stamped as fire resistant.
The whistleblower alerted police and an investigation began.
The court heard that Laverty had his own glass business but had gone bankrupt, so the company was taken over by his son under a new name.
He was an employee of his son's business when the fraud occurred.
A judge described the case as "chilling".
Referring to potential harm to members of the public in a fire, he said: "By the grace of God it was avoided but that's no thanks to you."
The judge added that because of the extreme financial pressures Laverty had been under and mental difficulties he had experienced because of those, he was prepared to "temper justice with mercy".
Members of Laverty's family wept as he was sentenced to two years - one year to be served in prison and the other on licence.
A police spokesperson said Laverty's actions were "absolutely reckless".
They added: ""This was a fraud designed to make large amounts of money but which put lives, many of them vulnerable lives, at risk."

Tarzan has in the past dragged logs from the Migdale Rock Site of Special Scientific Interest in Ledmore and Migdale Woods in Sutherland.
The horse caused less damage to rare plants than modern forest machinery.
Tarzan has been put to use at the Highland Folk Museum in Newtonmore where woodland is being thinned out.
Trees in a dense plantation of Scots pine have been felled to improve it as a habitat for wildlife including red squirrels.
Meanwhile, Scots pine woods on a nature reserve at the most northerly estuary on Scotland's east coast are to be given greater protection.
Scottish Natural Heritage (SNH) plans to control deer numbers and remove non-native plants at the site at Loch Fleet near Golspie in Sutherland.
SNH said Scots pine trees in the area were in an "unfavourable condition".
Work to remove rhododendron and sycamore, which are both not native to the UK, will start next month.
Loch Fleet National Nature Reserve covers a large tidal basin surrounded by dunes, salt marsh and pine woods.
A County Antrim man has been jailed for a year for selling fake fire safety glass that was later installed at schools, universities and hospitals.
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A horse used in logging operations in a fragile wildlife habitat has been hauling timber in woodland at a museum of Highland life.