HVAC Ventilation Design 3

Question 1

What is the purpose of the 'uncorrected outdoor air intake' (Vou) calculation in ASHRAE 62.1's Ventilation Rate Procedure?

Accepted Answer

To determine outdoor air needed before accounting for system efficiency

Answer

Vou represents the total system outdoor air requirement before applying the system ventilation efficiency correction factor (Ev).

Question 2

A building with a high window-to-wall ratio in a mild climate is best suited for which passive ventilation strategy?

Accepted Answer

Cross ventilation

Answer

Cross ventilation relies on wind-driven airflow through windows on opposite or adjacent walls, effective when openings are well-positioned and climate is mild.

Question 3

Which duct leakage class per SMACNA represents the tightest construction standard?

Accepted Answer

Class 1

Answer

SMACNA Class 1 (formerly Class A) allows only 1 cfm per 100 sq ft of duct surface at 1 inch w.g. and represents the most airtight construction.

Question 4

In displacement ventilation design, supply air is introduced at which location?

Accepted Answer

Low on the wall or floor level

Answer

Displacement ventilation supplies cool, fresh air at low velocity near the floor, allowing it to rise naturally as it absorbs heat and contaminants from occupants.

Question 5

What is the ASHRAE 62.1 term for the ratio of outdoor air to total supply air at the zone level?

Accepted Answer

Zone outdoor air fraction (Zpz)

Answer

Zpz (zone outdoor air fraction) equals the zone outdoor airflow (Vbz) divided by the zone supply airflow (Vpz) and is used to calculate system-level efficiency.

HVAC Practice Test

HVAC Practice Test

HVAC Ventilation Design 3