Iowa Administrative Code › Agency 661 - Public Safety Department › Chapter 303 - State Building Code - Requirements for Energy Conservation in Construction › Rule 661-303.2 - Residential Energy Code

Current through Register Vol. 47, No. 3, July 24, 2024
The International Energy Conservation Code -Residential
				Provisions, 2012 edition, published by the International Code Council, 5203
				Leesburg Pike, Suite 600, Falls Church, VA 22041, is adopted by reference as
				the residential energy code of the state of Iowa building code, applicable to
				residential construction limited to three or fewer stories throughout the state
				of Iowa, with the following amendments:
Delete section R101.1.
Delete section R101.2 and insert in lieu thereof the following
				new section:
R101.2 Scope. This code applies to residential buildings and
				the building sites and associated systems and equipment as defined pursuant to
				661-subrule 303.1(2). The remodeling or renovation of one- and two-family
				dwelling units is not within the scope of this code.
Delete section Rl03.3.1.
Delete section R103.3.2.
Delete section R103.3.3.
Delete section R104.1 and insert in lieu thereof the following
				new section:
R104.1 General. Construction or other work that is required to
				be inspected by state law or local ordinance shall be in accordance with
				sections R104.2 through R104.8. The state fire marshal shall have authority to
				perform audits to ensure compliance with the requirements of this code. When
				local governments conduct compliance audits, the information may be provided to
				the Department of Energy or to the state fire marshal in a timely way. Local
				governments may contract with the state fire marshal to conduct audits.
Delete sections R108 and R109 and all sections contained
				therein.
Delete section R402.1.1 and insert in lieu thereof the
				following new section:
R402.1.1 Insulation and fenestration criteria. The building
				thermal envelope shall meet the requirements of Table R402.1.1 based on the
				climate zone specified in chapter 3.
Table R402.1.1
Table R402.1.1 Insulation and Fenestration Requirements by
				Componenta
Climate Zone
Fenestration U-Factor 
						b
Skylight
U-Factor
b
Glazed
Fenestration
SHGC 
						b,e
Ceiling R-Value
Wood Frame
Wall R-Value
Mass
Wall
R-Value
i
Floor R-Value
Basement
Wall R-Value
c
Slab R-Value & Depth
d
Crawl
Spacec
Wall
R-Value
1
NR
.75
.25
30
13
3/4
13
0
0
0
2
.40
.65
.25
38
13
4/6
13
0
0
0
3
.35
.55
.25
38
20 or 13+5h
8/2013
19
5/2013f
0
5/2013
4
.35
.55
.40
49
20 or 13+5h
8/2013
19
10/2013
10,2ft
10/2013
5
.32
.55
NR
49
20 or 13+5h
13/17
30g
15/19
10,2ft
15/19
6
.32
.55
NR
49
20 or 13+5h
15/20
30g
15/19
10,4ft
15/19
7&8
.32
.55
NR
49
20+5 or 13+10h
19/21
38g
15/19
10,4ft
15/19
aR-values are minimums. U-factors
				and SHGC are maximums. When insulation is installed in a cavity which is less
				than the label or design thickness of the insulation, the installed R-value of
				the insulation shall not be less than the R-value specified in the
				table.
bThe fenestration U-factor column
				excludes skylights. The SHGC column applies to all glazed fenestration.
				EXCEPTION: Skylights may be excluded from glazed fenestration SHGC requirements
				in Climate Zones 1 through 3 where the SHGC for such skylights does not exceed
				.30.
c"15/19" means R-15 continuous
				insulation on the interior or exterior of the home or R-19 cavity insulation at
				the interior of the basement wall. "15/19" shall be permitted to be met with
				R-13 cavity insulation on the interior of the basement wall plus R-5 continuous
				insulation on the interior or exterior of the home. "10/2013" means R-10
				continuous insulation on the interior or exterior of the home or R-13 cavity
				insulation at the interior of the basement wall.
dR-5 shall be added to the required
				slab edge R-values for heated slabs. Insulation depth shall be the depth of the
				footing or 2 feet, whichever is less in Climate Zones 1 through 3 for heated
				slabs.
eThere are no SHGC requirements in
				the Marine Zone.
fBasement wall insulation is not
				required in warm-humid locations as defined by Figure R301.1 and Table
				R301.1.
g Or insulation sufficient to fill
				the framing cavity, R-19 minimum.
hFirst value is cavity insulation;
				second value is continuous insulation or insulated siding. Therefore, "13+5"
				means R-13 cavity insulation plus R-5 continuous insulation or insulated
				siding. If structural sheathing covers 40 percent or less of the exterior,
				continuous insulation R-value shall be permitted to be reduced by no more than
				R-3 in the locations where structural sheathing is used - to maintain a
				consistent total sheathing thickness.
iThe second R-value applies when
				more than half the insulation is on the interior of the mass wall.
Delete section R402.4.1.2 and insert in lieu thereof the
				following new section:
R402.4.1.2 Testing. The building or dwelling unit shall be
				tested and verified as having an air leakage rate not exceeding 5 air changes
				per hour in Climate Zones 1 and 2, and 4 air changes per hour in Climate Zones
				3 through 8. Testing shall be conducted with a blower door at a pressure of 0.2
				inches w.g. (50 pascals). Where required by the code official, testing shall be
				conducted by an approved third party. A written report of the results of the
				test shall be signed by the party conducting the test and provided to the code
				official. Testing shall be performed at any time after creation of all
				penetrations of the building thermal envelope.
During testing:
1.
			 Exterior windows and doors, fireplace and stove doors shall be closed, but not
			 sealed beyond the intended weather stripping or other infiltration control
			 measures;
2. Dampers including
			 exhaust, intake, makeup air, backdraft and flue dampers shall be closed, but
			 not sealed beyond intended infiltration control measures;
3. Interior doors, if installed at the time
			 of the test, shall be open;
4.
			 Exterior doors for continuous ventilation systems and heat recovery ventilators
			 shall be closed and sealed;
5.
			 Heating and cooling systems, if installed at the time of the test, shall be
			 turned off; and
6.  Supply and
			 return registers, if installed at the time of the test, shall be fully open.
Delete section R403.2.2 and insert in lieu thereof the
				following new section:
R403.2.2 Sealing (mandatory). Ducts, air handlers, and filter
				boxes shall be sealed. Joints and seams shall comply with either the
				International Mechanical Code or International Residential Code, as
				applicable.
Exceptions:
1.
			 Air-impermeable spray foam products shall be permitted to be applied without
			 additional joint seals.
2. Where a
			 duct connection is made that is partially inaccessible, three screws or rivets
			 shall be equally spaced on the exposed portion of the joint so as to prevent a
			 hinge effect.
3. Continuously
			 welded and locking-type longitudinal joints and seams in ducts operating at
			 static pressures less than 2 inches of water column (500 Pa) pressure
			 classification shall not require additional closure systems.
Duct tightness shall be verified by either of the
				following:
1. Post construction test:
			 Leakage to outdoors shall be less than or equal to 4 cfm (113.3 L/min) per 100
			 square feet (9.29 m2) of conditioned floor area or
			 total leakage shall be less than or equal to 6 cfm (170 L/min) per 100 square
			 feet (9.29 m2) of conditioned floor area when tested
			 at a pressure differential of 0.1 inches w.g. (25 Pa) across the entire system,
			 including the manufacturer's air handler enclosure. All register boots shall be
			 taped or otherwise sealed during the test.
2. Rough-in test: Total leakage shall be less
			 than or equal to 6 cfm (170 L/min) per 100 square feet (9.29
			 m2) of conditioned floor area when tested at a
			 pressure differential of 0.1 inches w.g. (25 Pa) across the system, including
			 the manufacturer's air handler enclosure. All registers shall be taped or
			 otherwise sealed during the test. If the air handler is not installed at the
			 time of the test, total leakage shall be less than or equal to 3 cfm (85 L/min)
			 per 100 square feet (9.29 m2) of conditioned floor
			 area.
Testing shall be conducted by an approved third party. A
				written report of the results shall be signed by the party conducting the test
				and provided to the code official.
Exception: The duct leakage test is not required for ducts and
				air handlers located entirely within the building thermal envelope unless
				cavities are used for returns.
Delete section R403.2.3 and insert in lieu thereof the
				following new section:
R403.2.3 Building cavities (mandatory). Building framing
				cavities shall not be used as supply ducts. Building framing cavities may be
				used as return ducts if both of the following conditions
				exist:
1. Ducts must be
			 tested for duct leakage in accordance with section R403.2.2.
2. Exterior wall cavities shall not be used
			 for return ducts.