Lecture Notes #14

Question 1

What are the typical applications of a down blast fan type?

Answer 1

washrooms and non-hazardous applications

Question 2

When would you use an upward discharge exhaust fan?

Answer 2

for contaminated exhaust air or when air is having grease particles like in kitchens.

Question 3

Define “throw” in regards to air diffusion?

Answer 3

the distance the air is projected out from the outlet face. these are to be measured as a velocity, not a distance measurement (i.e. T150, T50, etc.)

Question 4

Define “drop” in regards to air diffusion?

Answer 4

the vertical distance that air extends below the ceiling. This is due to cool air being introduced into a warmer space

Question 5

Define “spread” in regards to air diffusion?

Answer 5

Defined as divergence of the primary air jet as it discharges from the air outlet.

Question 6

What is Surface effect? (also known as coanda effect)

Answer 6

This occurs when an air mass with velocity moves near a surface. The air mass tends to move along that surface until the air mass velocity diminishes to around 50 fpm.

Question 7

What’s the maximum allowable airflow velocity in an “occupied space”?

Answer 7

50 FPM