Day 3 of testimony in the Deutsche Bank firefighter-manslaughter trial left one juror visibly struggling to stay awake throughout the afternoon.

Prosecution witness E.G. Ignacio, a project manager for Bovis Lend Lease — the general contractor for demolition of the 9/11-damaged former bank building — spent much of the afternoon testifying about standpipes.

Meanwhile, the snoozy male juror, who sat in the back row, repeatedly closed his eyes, head nodding forward for seconds at a time before he snapped to alertness.

Prosecutors plan to spend three months using technical testimony to prove that three construction workers knowingly created a fatal hazard by failing to repair a broken standpipe to carry crucial water.

Firefighters Robert Beddia and Joseph Graffagnino died on Aug. 18, 2007, after being trapped without water on the burning 14th floor.

Defense lawyers for Mitchel Alvo, Salvatore DePaola and Jeffrey Melofchik say other factors are to blame — including blocked stairwells, no sprinklers, and decisions by fire supervisors to let firefighters enter the deathtrap.