EXAC EXAM 3 QUESTIONS AND
CORRECT ANSWERS
Factors affecting human comfort - Answer- 1. Air temp
2. Relative humidity
3. Mean radiant temperature
4. Air motion
Air Temp and Mean Radiant Temp (MRT) - Answer- Higher MRT - Lower Air Temp
Air Temp and Relative Humidity - Answer- Higher Humidity - Lower Temp
Air Temp and Air Motion - Answer- Lower the temp, lower the air motion
3 Sources of heat gain - Answer- 1 - Infiltration: Air through cracks. Ensure tight seal of
air barrier
2 - Radiation: Through glass. Increase glass thermal performance (low e, argon filled,
triple glazed)
3 - Convection/ radiation: Poorly insulated walls. Increase wall insulation
HVAC - Min Maintenance - Answer- - All air (VAV, CAV)
HVAC - Min floor space and floor height - Answer- - Wall terminal (packaged units)
- Hydronic (All water)
- Electric radiant
HVAC - Min Visual - Answer- - All Air
HVAC - Min Noise - Answer- - Low velocity single duct VAV / CAV
- All water (Hydronic)
HVAC - Max Individual Control - Answer- - Hydronic (All Water)
- Packaged Terminal
- VAV
- Dual duct
- Fan coil terminals
- Induction units
- Multi zone
HVAC - Max Control Air Quality - Answer- - All Air
, Static Load vs Dynamic Load - Answer- 1. Static Load: Applied slowly
2. Dynamic Load: Applied suddenly
6 Types of static loads - Answer- 1. Live load (Occupant / Snow)
2. Dead load (self weight / mech)
3. Settlement loads (diff settlement)
4. Ground pressure (soil mass)
5. Hydrostatic Pressure
6. Impact load
2 Types Dynamic Loads - Answer- 1. Wind
2. Earthquake
Shear Strength Soil - Answer- Ability to resist displacement when forces applied
1 - Cohesive soils (clay, silt) retain strength when unconfined (high angle of repose)
2 - Non cohesive soils (gravel, sand) require confined forces and have shallow angle of
repose
Structural stresses - Answer- 1. Compression
2. Tension
3. Shear
4. Bending
5. Torsion (twisting)
Heating and cooling loads - Answer- 1. Heating load: Heat loss btu/hr
2. Cooling load: Heat gain btu/hr
Test for soil permeability - Answer- Percolation test
Septic system distances - Answer- Tank and Field
1. From wells - 100' (30m)
2. From Streams - 50' (15m)
3. From PL or Buildings - 10' (3m)
Septic Tank Drainage - Answer- 1 - Drainage field: Absorption trenches that drain into
field, seeps into soil
2- Seepage Pit: Use when soil is absorbent and water table 2'-0" below pit
3 - Subsurface sand filter: Use when the other two can't be used. Distribution pipes
surrounded by graded gravel
Heating systems - Answer- 1. Forced air
2. Hot water
3. Electrica
4. Radiant
5. Active solar
CORRECT ANSWERS
Factors affecting human comfort - Answer- 1. Air temp
2. Relative humidity
3. Mean radiant temperature
4. Air motion
Air Temp and Mean Radiant Temp (MRT) - Answer- Higher MRT - Lower Air Temp
Air Temp and Relative Humidity - Answer- Higher Humidity - Lower Temp
Air Temp and Air Motion - Answer- Lower the temp, lower the air motion
3 Sources of heat gain - Answer- 1 - Infiltration: Air through cracks. Ensure tight seal of
air barrier
2 - Radiation: Through glass. Increase glass thermal performance (low e, argon filled,
triple glazed)
3 - Convection/ radiation: Poorly insulated walls. Increase wall insulation
HVAC - Min Maintenance - Answer- - All air (VAV, CAV)
HVAC - Min floor space and floor height - Answer- - Wall terminal (packaged units)
- Hydronic (All water)
- Electric radiant
HVAC - Min Visual - Answer- - All Air
HVAC - Min Noise - Answer- - Low velocity single duct VAV / CAV
- All water (Hydronic)
HVAC - Max Individual Control - Answer- - Hydronic (All Water)
- Packaged Terminal
- VAV
- Dual duct
- Fan coil terminals
- Induction units
- Multi zone
HVAC - Max Control Air Quality - Answer- - All Air
, Static Load vs Dynamic Load - Answer- 1. Static Load: Applied slowly
2. Dynamic Load: Applied suddenly
6 Types of static loads - Answer- 1. Live load (Occupant / Snow)
2. Dead load (self weight / mech)
3. Settlement loads (diff settlement)
4. Ground pressure (soil mass)
5. Hydrostatic Pressure
6. Impact load
2 Types Dynamic Loads - Answer- 1. Wind
2. Earthquake
Shear Strength Soil - Answer- Ability to resist displacement when forces applied
1 - Cohesive soils (clay, silt) retain strength when unconfined (high angle of repose)
2 - Non cohesive soils (gravel, sand) require confined forces and have shallow angle of
repose
Structural stresses - Answer- 1. Compression
2. Tension
3. Shear
4. Bending
5. Torsion (twisting)
Heating and cooling loads - Answer- 1. Heating load: Heat loss btu/hr
2. Cooling load: Heat gain btu/hr
Test for soil permeability - Answer- Percolation test
Septic system distances - Answer- Tank and Field
1. From wells - 100' (30m)
2. From Streams - 50' (15m)
3. From PL or Buildings - 10' (3m)
Septic Tank Drainage - Answer- 1 - Drainage field: Absorption trenches that drain into
field, seeps into soil
2- Seepage Pit: Use when soil is absorbent and water table 2'-0" below pit
3 - Subsurface sand filter: Use when the other two can't be used. Distribution pipes
surrounded by graded gravel
Heating systems - Answer- 1. Forced air
2. Hot water
3. Electrica
4. Radiant
5. Active solar
