PROBLEM $7.(20$ POINTS$)$

A conference room in a building in Toronto, Ontario, has two exposed walls $($front and back$)$ and

measures $120$ ft long, $60$ ft wide and has a ceiling height of $20$ ft $.$ The conference room is on the

second floor of a four$-$story building, and is not mechanically ventilated. The conference room is

surrounded by conditioned space, left, right, up and down. Each of the exposed walls $($each $120$ ft

long$)$ contains $15$ windows. The windows are double$-$hung $($both upper and lower halves

operable$),$ wood framed, single glazed, non$-$weather$-$stripped, average fit, and each measures $3$ ft

wide by $5$ ft tall. The window frame$-$wall joint is caulked. One of the exposed walls faces

prevailing wind direction. The pressure difference between the outside and inside is estimated to

be $0\mathrm{.}2$ in water $($outside pressure is greater$).$