EXAMPLE $-$ AIR FLOW IN DUCTS

A ventilation system is supplying air to a small office and meeting room, as detailed below.

The office and meeting room require air change rates per hour $($ACH$)$ of $4$hr$^(-1)$ and $5$hr$^(-1)$

respectively. They each are supplied by the same main supply duct of $400$ mm diameter, that

then branches to each room, by a $70$ mm circular duct to the meeting room, and splitting to

supply the office by two evenly distributed ducts of $350$mm diameter each.

Calculate the total volume flow rate of the main duct, and then the supply velocities given

the duct sizes provided.

Construct a table, and calculate the volume of the rooms from the first table. $($solve and sketch please$)$