mechanical ventilation

Question 1

Purpose of Ventilation

Answer 1

• provide oxygen for human respiration
• reduce concentration of CO2
• provide sufficient air circulation for the comfort
• dilute gaseous contaminants to below max levels
• dilute airborne particles concentration in industrial premises dur to industrial processes

Question 2

types of ventilation

Answer 2

nature or mechanical

Question 3

calculation questions formula thingy

Answer 3

total vol of air X air change needed = ventilation rate

Question 4

Exit Staircases

Answer 4

• mechanical ventilation need 4 air-change per hour
• independent system of supply mode only
• supply from air directly from external, no less than 5m from exhaust discharge opening
• staircases serving more than 4 storeys - vertical
  duct and outlets distributed at alternate floor.
• POSITIVE PRESSURE

Question 5

jet fans

Answer 5

• replace ductwork
• create & control air movement within the space
• kinda like grilles in a traditional ducted system
• allow control over supply & exhaust air movement within car park

Question 6

duct fans

Answer 6

• Traditionally, ventilation of basement car parks has been achieved
• by supplying outdoor air at a high level into the space via a system of supply air fan and distribution ductwork,
• terminating at a number of well-distributed supply air grilles and extracting air also via a system of exhaust fans and exhaust ductwork fitted with low and high level exhaust air grilles.

Question 7

fire damper

Answer 7

• containing fire within specific enclosures

Question 8

where are fire dampers installed?

Answer 8

• where ducts penetrate through floor slabs & firewalls

Question 9

how do fire dampers work?

Answer 9

• fusible links that melt at 70 degrees
• shuts off damper
• rated for 1-2 hours resistance depending on rating of fire barrier

Question 10

types of fans

Answer 10

• centrifugal fans
• axial fans

Question 11

centrifugal fans

Answer 11

• Air flows into the impeller axially and is discharged radially into the volute of the casing.
• suitable for medium to low volume flow rates
  at medium to high pressures

Question 12

Axial fans

Answer 12

Air enters and leaves the axial fan along the axis of the shaft. They are used
for high to medium flow rates at medium to low pressures

Question 13

three groups of axial fans

Answer 13

• propeller
• tube axial
• vane axial