Building Services Engineering 5th Edition Handbook

120 Heating
27. Which is not correct about the heating hot water, HHW, source:
1. Often called a boiler.
2. A boiler is a gas-fired or electrically heated device which generates steam.
3. HHW circulating at 75 ◦ C is steam at atmospheric pressure when it leaks out of the pipes.
4. Is usually a gas-fired water heater at 75 ◦ C.
5. Is a sealed water system having a thermal expansion tank.
28. Outstation and main control boxes of a building management system are normally
found in:
1. Terminal air-conditioning units.
2. Plant rooms.
3. Computer rooms.
4. Services shafts.
5. The office of the building management personnel.
29. Programming and commissioning of a building management system is carried out:
1. With a screwdriver.
2. At the server computer.
3. Remotely through the internet.
4. By calibrating room air temperature sensors with a thermometer.
5. With a laptop computer communicating directly with each control box.
30. What types of cable system are used for building management system communications
cables?
1. 240 V alternating current.
2. Screened TV Arial cable.
3. RS485 and RS232 copper 10 V twisted pair.
4. Mineral-insulated copper conduit.
5. Any earthed cable.
31. What is a room-sealed gas appliance? More than one correct answer.
1. Gas-fired heater installed outside a room in the outside air.
2. Gas-fired warm-air ducted heater installed within a sealed cupboard.
3. Any balanced-flue gas appliance.
4. No such thing.
5. Gas-fired heater where combustion air enters the unit directly from outdoors through
the same wall terminal where flue gas is discharged into the outdoor air.
32. What does an air curtain do?
1. Provides a security screen at an international airport flight passenger entrance.
2. A draught to overcome prevailing wind direction at a doorway.
3. Creates a downward or horizontal air stream across an open doorway.
4. Makes entering a building very draughty.
5. Wastes energy from fan power.