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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 @50PA141 Site Built homes
0
200
400
600
800
1000
1200
1400
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
Ex
teri
or
Le
ak
ag
e C
FM
50
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
0
100
200
300
400
500
600
700
800
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
CFM
@ %
PA
fail pass
Duct Leakage to Exterior @50PA With all Pans <1 PaMobile Homes
0
50
100
150
200
250
300
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
CF
M@
50P
a
% of Floor Area of Duct Leakage to Exterior @50PA all Pans Below 1Pa - Passed Pressure Pan Rule
0.0%
5.0%
10.0%
15.0%
20.0%
25.0%
30.0%
35.0%
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
Perc
ent o
f flo
or a
rea
% of Floor Area of Duct Leakage to Exterior @50PA at least one above 1Pa - Failed Pressure Pan Rule
-5.0%
5.0%
15.0%
25.0%
35.0%
45.0%
55.0%
65.0%
75.0%
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49
Chart ID Number
Leak
age
as P
erce
nt o
f Flo
or A
rea