Building Engineering Mechanical Engineering 4

Question 1

What does the MERV rating system classify for HVAC air filters?

Accepted Answer

Minimum efficiency reporting value for particle capture efficiency

Answer

MERV (Minimum Efficiency Reporting Value) rates filters from 1–16 based on their ability to capture particles of specific sizes, with higher numbers indicating finer filtration.

Question 2

When sizing an expansion tank for a closed hydronic system, what is the primary variable the tank must accommodate?

Accepted Answer

Volume change of water as it heats from fill temperature to operating temperature

Answer

Water expands as it heats; the expansion tank provides a sealed air cushion to absorb this volume increase and keep system pressure within design limits.

Question 3

According to ASHRAE 90.1 energy code, what control is required for HVAC systems serving spaces with variable occupancy to reduce energy use during unoccupied hours?

Accepted Answer

Occupancy scheduling with setback temperature control

Answer

ASHRAE 90.1 requires programmable setback controls that reduce heating and cooling set points during unoccupied periods, reducing energy consumption.

Question 4

What is 'hydronic balancing' and why is it performed on a new building's heating/cooling water system?

Accepted Answer

Adjusting flow rates at each terminal to match design values so all zones receive adequate capacity

Answer

Hydronic balancing adjusts balancing valves so each coil or terminal receives its design flow rate, preventing overflowing near terminals and starving remote ones.

Question 5

A mechanical engineer specifies 'low-leakage' dampers in a pressurized air system. Which AMCA rating class would meet the most stringent leakage requirement?

Accepted Answer

AMCA Class I

Answer

AMCA Class I dampers have the lowest permissible leakage rate, making them appropriate for critical pressurized applications like smoke control and clean rooms.

Building Engineering Practice Test

Building Engineering Practice Test

Building Engineering Mechanical Engineering 4