Transcript Proposed Changes to PTCS Duct Sealing Specifications & Standards

Proposed Changes to PTCS Duct
Sealing Specifications & Standards
RTF
January 23rd 2033
Bob Davis & Bruce Manclark
Current Specifications
• Systems must be sealed with mastic
– Mastic comes out of a bucket - not off of a roll
– UL 181 tape may be used to provide service access
• Worst case depressurization test must be below minus 3 Pascals
• Must have UL listed Carbon Monoxide alarm if combustion
appliances are present
• Testing must be performed by a Climate Crafter certified technician
• Room by room heat loss required for duct sizing in accordance with
industry standards
• No recommended changes
Current Tightness Standards
• New Construction
– Total leakage or leakage@ 50PA to exterior
cannot exceed:
• 6% of floor area (2,000 sq. ft. house max leakage
of 120 CFM) OR
• 75 CFM
• No recommended changes
Current Tightness Standards
• Existing Homes
– Achieve a 50% reduction in exterior leakage
@50PA by duct sealing
– Leakage to exterior less than 10% of
conditioned floor area (2,000 sq. ft. house
max leakage of 200 CFM)
– All pressure pans less than 1 Pascals
– Proposed changes: Eliminate the use of
Pressure Pans as a standard
Why Eliminate Pressure Pans
• Not a solid standard
– Many variables other
than holes to the
exterior affect their
readings
•
•
•
•
•
Filter
Inside coils
Sq. inches of registers
Other inside leakage
Tightness of seal
(carpet vs. bare floor)
Why Eliminate Pressure Pans
•
Crews receive inconsistent
feedback
– Small reductions in holes may
mean large pressure pan
reductions
– Large reductions in holes may
mean small pressure pan
reductions
• Impossible to make energy
savings projections from
pressure pan numbers
Side by Side Comparisons of
Pressure Pans and Duct Blasters
• 141 unsealed duct systems in western
Oregon
– All crawl space homes
– Only shows average pressure pan numbers
Duct Leakage to Exterior @50PA
141 Site Built homes
1400
Exterior Leakage CFM50
1200
1000
800
600
400
200
0
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23
Average Pan Number
Mobile Home Data
• 41 mobile homes in Eugene, Oregon
– Good variety of double wides and single
wides
– Good variety of ages
– Pre and post results on same homes
Mobile Home Exterior Duct Leakage @50PA for Fail and Pass Rule - all Pans < 1Pa
fail
pass
800
700
CFM @ % PA
600
500
400
300
200
100
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48
Chart ID Number
Duct Leakage to Exterior @50PA With all Pans <1 Pa
Mobile Homes
300
CFM@ 50Pa
250
200
150
100
50
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
Chart ID Number
% of Floor Area of Duct Leakage to Exterior @50PA all Pans Below 1Pa - Passed Pressure Pan
Rule
35.0%
Percent of floor area
30.0%
25.0%
20.0%
15.0%
10.0%
5.0%
0.0%
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Chart ID Number
18
19
20
21
22
23
24
25
26
27
28
29
30
% of Floor Area of Duct Leakage to Exterior @50PA at least one above 1Pa - Failed Pressure
Pan Rule
65.0%
55.0%
45.0%
35.0%
25.0%
15.0%
Chart ID Number
49
47
45
43
41
39
37
35
33
31
29
27
25
23
21
19
17
15
13
9
7
5
11
-5.0%
3
5.0%
1
Leakage as Percent of Floor Area
75.0%