1. No category

1
Why ventilate?
•
•
•
•
•
Dilute contaminants
Control or aggravate humidity
Comfort or lack of cooling
Odors
Provide oxygen
2
Outdoor Air (cfm/person)
History of Minimum Ventilation
Recommendations
60
55
50
45
40
35
30
25
20
15
10
5
1825
smoking
62-89
Billings
1895
F l u g g e
1 95 0
smoking
62-81
A S H R
ASHRAE 6 29 - 8
62-73
Nightengale
1865
Yaglou
1936
Tredgold
ASHRAE 62-81
1836
Reid
1844
1850
1875
1900 1925
1950
1975 2000
3
2500
5
equilibrium co2
4.5
sbs data
2000
sbs curve fit
4
1500
3
2.5
1000
2
1.5
500
1
0.5
0
0
0
20
40
60
80
100
120
Ventilation (cfm/person)
Sick Building Syndrome data from Jan Sundell Swedish Office Building Study4
SBS Rtsk Factor
Equilibrium CO2 (ppm)
3.5
More than a Fan
• Exhaust vent point sources to
the outside
– Kitchen, bathroom, dryers (except
condensing dryers), combustion
devices, laundries
• Provide dilution ventilation
– Exhaust, supply, both
• Effective distribution
– Central air handlers?
– Baseboard or radiant heat?
• Air seal enclosure
– 1.25 in2 per 100 ft2 enclosure
• Multi-family issues
5
Ventilation Standards and Codes?
• IRC, IMC 2003
– 4 ft2window/100ft2 or 0.35 ach (not less than 15 cfm/person)
mechanical
– Bath 1.5 ft2 window(1/2operable) or 50 cfm intermittent or 20 cfm
continuous exhaust to outside
– Kitchens 100 cfm intermittent, 25cfm continuous
– Dryer must exhaust
• ASHRAE 62.2 2003 Residential Buildings
– 7.5 cfm/person+1cfm/100sq.ft. fan powered
• assumes additional 2cfm/100ft2 infiltration
• <4500 infiltration degree day exclusion
– Exhaust: Intermittent 100cfm kitchen, 50 cfm bath, or continuous 5
ach kitchen , 20 cfm bath (continuous exhaust fans can be used to
meet the dilution requirement)
– Dryer must exhaust; range hood required if flow less than 5 ach
– Some noise and installation requirements
6
Local exhaust
-Furnace
-Dryer
-Bathroom
-Kitchen
7
8
9
Door closed
Door Open
10
11
12
Fog never forms at 81 cfm
13
Recommendations for
Bathroom Exhaust
• Grille within 6 inches of ceiling
• 20 cfm continuous
• 80 cfm boost controlled by motion sensor
(light switch of timer switch ok)
14
15
Exhaust fan in
basement,
vented through
rim joist fitting
16
Is it working?
17
Is it the right amount?
18
19
20
• Compartmentalize
• Provide exhaust
for baths and
kitchens
• Stack effect in
cold climates
21
Exhaust System Components
ƒ Grilles in
apartments or
corridors
ƒ Bathrooms
ƒ Kitchens
ƒ Mushroom fans
on roofs
22
23
24
25
26
flow
pressure
27
28
Multi-family ventilation issues
29
• Each unit airsealed to 1.25 in2 per 100 ft2
enclosure
• No transfer to neighbors when system’s on
• 4% transfer when one unit turned off
• 1-3% exhaust re-enters through trickle
vents worst case
30
31
32
Tightness Specifications
LEED ETS multifamily
Battery Park City Multifamily
• 1.25 ELA/ 100ft2 enclosure
• 22.8 cfm50/100ft2 enclosure
• ~ 5-6ACH50
33
34
Ventilation rate
53 cfm
73 F
31 cfm
10 F
53 cfm
NPL - 3’
22 cfm
31 cfm
35
Ventilation rate
80 cfm
gain 27 cfm
50
cfm
73 F
37 cfm
10 F
30 cfm
NPL - 5’
43 cfm
37 cfm
36
Ventilation rate
80 cfm
50
cfm
80 cfm
73 F
23 cfm
10 F
NPL - 1’
7 cfm
23 cfm
37
Ventilation rate
112 cfm
gain 59 cfm
100
cfm
12 cfm
73 F
43 cfm
10 F
NPL - 7’
69 cfm
43 cfm
38
Ventilation rate
103 cfm
gain 50 cfm
50
cfm
50
cfm
10 F
73 F
31 cfm
53 cfm
NPL - 3’
22 cfm
31 cfm
39