CMI CMI HVAC Systems & Ventilation Inspection 2

Question 1

What is 'thermal bypassing' in duct systems and how does it contribute to mold growth?

Accepted Answer

Unsealed duct connections allow warm humid air to contact cold duct surfaces, causing condensation and mold growth

Answer

Thermal bypassing refers to insulation that is too thick, blocking heat exchange

Answer

It describes a situation where heated air skips certain rooms

Answer

Thermal bypassing is a positive feature that improves energy efficiency

Question 2

Which ASHRAE standard provides ventilation rate recommendations that, when not met, can contribute to elevated indoor humidity and mold risk?

Accepted Answer

ASHRAE 62.1

Answer

ASHRAE 90.1

Answer

ASHRAE 55

Answer

ASHRAE 15

Question 3

A mold inspector discovers mold growth on supply diffusers throughout a commercial building. What is the most likely underlying cause?

Accepted Answer

The supply air is below the dew point of the room air, causing condensation on the diffuser surfaces

Answer

The diffusers are made of a material that supports mold growth regardless of moisture

Answer

Mold spores have contaminated only the diffusers and not the ductwork

Answer

High air velocity through diffusers prevents condensation

Question 4

What indoor relative humidity range is recommended by the EPA to minimize mold growth in residential buildings?

Accepted Answer

30–50%

Answer

20–30%

Answer

55–65%

Answer

60–70%

Question 5

When inspecting a bathroom exhaust fan for mold-related concerns, what is the most critical functional check?

Accepted Answer

Verify that the fan is vented to the exterior and not into an attic or wall cavity

Answer

Confirm the fan produces at least 200 CFM of airflow

Answer

Check that the fan is on the same circuit as the HVAC system

Answer

Ensure the fan has a built-in HEPA filter

Question 6

What is the purpose of an energy recovery ventilator (ERV) in preventing mold in a tightly sealed building?

Accepted Answer

It brings in fresh outdoor air while transferring heat and moisture between airstreams to prevent humidity extremes

Answer

It recirculates indoor air through HEPA filters without introducing outdoor air

Answer

It heats incoming outdoor air to 100°F to kill mold spores before distribution

Answer

ERVs are designed to reduce radon levels, not humidity