BLDG 371 – Building Service Systems
Assignment #2
Due date: February, 20th 2021
1- How large is the duct required to carry 20,000 CFM of air if the velocity is not to exceed
1600 ft/min? Calculate the lost pressure due to air velocity in this duct. What is the
equivalent rectangular duct with equal friction and capacity if one side is 26 in?
2- Compute the loss in total pressure for each run of the duct system shown below. The ducts
are of round cross section. Turns and fittings are as shown. Use the equivalent length
approach and SI units.
3- The duct system shown below is part of a complete air-distribution system. Diffuser boots
turn up 90 degrees and all elbows are pleated. Size the various sections of the system, using
the equal-friction method and round pipe. Velocity in the main duct should be 900 fpm.
Compute the actual loss in total pressure in branch A, assuming that the shown amount of air
is flowing.
1
Assignment #2
Due date: February, 20th 2021
1- How large is the duct required to carry 20,000 CFM of air if the velocity is not to exceed
1600 ft/min? Calculate the lost pressure due to air velocity in this duct. What is the
equivalent rectangular duct with equal friction and capacity if one side is 26 in?
2- Compute the loss in total pressure for each run of the duct system shown below. The ducts
are of round cross section. Turns and fittings are as shown. Use the equivalent length
approach and SI units.
3- The duct system shown below is part of a complete air-distribution system. Diffuser boots
turn up 90 degrees and all elbows are pleated. Size the various sections of the system, using
the equal-friction method and round pipe. Velocity in the main duct should be 900 fpm.
Compute the actual loss in total pressure in branch A, assuming that the shown amount of air
is flowing.
1
