Construction and Building Materials Multiple Choice Questions & Answers (MCQs) on “Types of Ventilation”.
1. The term _________ is used to mean the free passage of clean air in a structure.
a) Circulation
b) Ventilation
c) Dissipation
d) Condensation
Answer: b
Clarification: In other words, the removal of all vitiated air from a building and its replacement with fresh air is known as ventilation. It is important from the engineering viewpoint for various reasons.
2. For comfortable working, the ___________ content should be limited to about 0.6% by volume.
a) Oxygen
b) Hydrogen
c) Carbon monoxide
d) Carbon dioxide
Answer: d
Clarification: It is observed that breathing is difficult when the amount of carbon dioxide by volume is about 6% and a man loses consciousness when it reaches about 10% or so. The more the amount of carbon dioxide, the more difficult is the breathing.
3. The difference of temperature between the outside air and inside air tends to the deposition of moisture in the room surfaces known as ___________
a) Ventilation
b) Diffusion
c) Condensation
d) Dissipation
Answer: c
Clarification: The proper and sufficient ventilation results in the absence of condensation. It can be effectively controlled by the provision of suitable ventilation of the room.
4. Where people are working, there has to be ______________ to cause proper ventilation of the premises.
a) Air change
b) Humidity
c) Temperature
d) Moisture
Answer: a
Clarification: The minimum and maximum rates of air change per hour is 1 and 60 respectively. If the rate of change is less than 1/hour, it will not create any appreciable effect of the ventilation system. On the other hand, at the rate of air changes more than 60/hour, it will result in discomfort due to high velocities of air.
5. The rate of amount of water vapour present to the amount it would have contained, had it been saturated, is known as the ___________ the temperature being same.
a) Relative humidity
b) Saturated air
c) Dry bulb temperature
d) Wet bulb temperature
Answer: a
Clarification: When a certain volume of air at a certain temperature contents as much water vapour as it can, it is said to be Saturated air. Generally, the air is not saturated at all times. But it contains a certain amount of water vapour in it.
6. For working a temperature of 21 degree Celsius, range of 30% to 70% of ____________ is desirable.
a) Saturated air
b) Dry bulb temperature
c) Relative humidity
d) Wet bulb temperature
Answer: c
Clarification: The value of relative humidity is obtained by comparing dry bulb and wet bulb temperature. For higher temperatures, the low humidity and greater air movements are necessary for removing greater portion of heat from the body.
7. The ________________ plays an important role in the comfort of persons affected by ventilation system.
a) Carbon monoxide
b) Purity of air
c) Volume of room
d) Health of occupant
Answer: b
Clarification: The air should be free from odours, organic matter, inorganic dust and unhealthy fumes of gases such as carbon monoxide, carbon dioxide and Sulphur Dioxide, etc. All the above impurities depend on the habits of occupants, volume of a room, source of ventilating air, etc.
8. It is quite evident that the incoming air for ventilation should be ________ in summer and ________ in winter before it enters the room.
a) cool, warm
b) warm, cool
c) humid, dry
d) dry, humid
Answer: a
Clarification: The usual difference of temperature between inside and outside is kept as about 8°C to 10°C. With regards to human comfort, the term effective temperature is used. It is an index which combines the effect of air movements, humidity and temperature.
9. __________________ is an index which combines the effect of air movement, humidity and temperature.
a) Saturated air
b) Effective humidity
c) Dry bulb temperature
d) Effective temperature
Answer: d
Clarification: Effective temperature indicates the temperature of air at which sensation of same degree of cold or warmth will be experienced as in quite a fully saturated at the same temperature. Thus, if two rooms have the same effective temperature, no change of temperature will be experienced by a person when he suddenly leaves one room and enters the room.
10. The value of ______________ depends on type of activity, geographical conditions, age of occupants, etc.
a) Saturated air
b) Relative humidity
c) Effective temperature
d) Condensation
Answer: c
Clarification: The popular values of effective temperature in winter and summer or 20°C and 22°C respectively. It should however be remembered that the effective temperature indicates same feeling of cool or warmth. But it results in human comfort only when it is correlated with humidity and air movements.
11. In ______________ system, the use is made of doors, windows, ventilators and skylights to make the room properly ventilated.
a) Artificial ventilation
b) Air conditioning
c) Natural ventilation
d) Mechanical ventilation
Answer: c
Clarification: Natural ventilation is useful for small buildings and it cannot be adopted for big offices, theatres, auditoriums, etc. The only advantage of the system is that it is economical in the sense that no special equipment is necessary for making the room adequately ventilated and that is affords living under natural conditions.
12. In _____________ system, some mechanical arrangement is adopted to provide enough ventilation to the room.
a) Natural ventilation
b) Skylight
c) Artificial ventilation
d) Man made
Answer: c
Clarification: Mechanical or Artificial ventilation has become popular due to recent change in notion regarding ventilation. At present, the ventilation is required not nearly to furnish warm air or cool air. But the ventilation system should provide air of such qualities regarding humidity, temperature, etc.
13. Exhaust system, supply system, air conditioning, etc. comes under ________ type of ventilation system.
a) Natural
b) Mechanical
c) Man made
d) Doors
Answer: b
Clarification: The mechanical system is costly, but it results in a considerable increase in the efficiency of the person under the command of the system. This system is adopted for big offices, banks, industrial plants, theatres, etc.
14. In ______________ system, the partial vacuum is created inside of the room by exhausting the vitiated inside air by fans or blowers.
a) Supply
b) Plenum
c) Air conditioning
d) Exhaust
Answer: d
Clarification: In exhaust system, the extraction of air from inside sets of the current of fresh air from outside to inside and thus, it becomes possible to provide fresh air to the room through doors and windows. The fans or blowers are installed at suitable places in the outside wall and they are connected to different rooms through duct system.
15. _______________ system is just the reverse of the exhaust system.
a) Air conditioning
b) Exhaust
c) Plenum
d) Supply
Answer: d
Clarification: Supply system consist in supplying fresh air to the room by installing input fans in outside walls. This system is used for ventilating rooms near an unusual quantity of heat or odours is not produced.