Building Services Engineering 5th Edition Handbook

176 Ventilation and air conditioning
87. Which is correct about commissioning air-duct systems?
1. Air-duct systems do not need to be inspected during commissioning.
2. All air ducts must be internally cleaned prior to commissioning.
3. All air ducts must be internally inspected with remote-controlled lamps and cameras
before use.
4. Rough internal projections, rivets and metal cuttings are removed by the commissioning
technician.
5. Air-duct systems are sealed in sections and pressure tested for an air-tightness standard
compliance.
88. Which is correct about noise in air-conditioning ducts?
1. Ducts are mounted on springs to isolate vibration from the building structure.
2. Fan and motor are solidly bolted to a concrete plant base to isolate noise and vibration.
3. Noise from sources within the building cannot enter air ducts and transfer elsewhere.
4. Fans have a flexible air-tight fabric connection with air-conditioning ducts to stop
transmission of vibration.
5. Noise created in one room cannot travel through an air conditioning-duct and enter
another room.
89. Which is not correct about chlorinated fluorocarbons?
1. R22 commonly used in large refrigeration systems such as chilled-water plant.
2. Contained within sealed refrigeration systems at below atmospheric pressure so never
leaks into atmosphere.
3. Used in halon fire extinguishing fluid.
4. Non-toxic.
5. Only exists at atmospheric pressure in gaseous form.
90. What happens to chlorinated fluorocarbons when released into the atmosphere?
1. Dissolved by nearby water and rain.
2. Harmlessly coexist in the atmosphere.
3. Vaporized and dispersed by wind and rain.
4. Degraded by ultraviolet solar radiation releasing chlorine into upper atmosphere that
remains there for many years.
5. Degraded by infrared solar radiation in the upper atmosphere releasing harmless oxides
of chlorine, carbon and fluorine.
91. Which factor is included in SBS assessment?
1. Poorly maintained mechanical equipment.
2. Time of day.
3. Shift work times.
4. Overbearing management style over workforce.
5. Illegal medication.
92. Which factor is not included in SBS assessment?
1. Inadequately clean working environment.
2. Staff not taking work breaks.
3. Dust in workspace.
4. Lighting glare.
5. Tiredness.