Washington Administrative Code › Title 51 - Enterprise Services, Department of (Building Code Council) › Chapter 51-11C - State Building Code adoption and amendment of the 2021 edition of the International Energy Conservation Code, Commercial › Section 51-11C-40630 - Section C406.3-Load management credits

Current through Register Vol. 24-14, July 15, 2024
C406.3
Load
			 management credits.
Load management measures installed in the building
			 that meet the requirements in Sections C406.3.1 through C406.3.7 shall achieve
			 the credits listed for the occupancy group in Table C406.3 or where
			 calculations required by Sections C406.3.1 through C406.3.7 create or modify
			 the table credits the credits achieved will be based upon the section
			 calculations.
Each load management measure shall require automatic controls
				activated by either utility demand response, utility price response signal,
				peak price period time control, or local building demand monitoring. Controls
				shall be capable of and configured to provide the required load management
				sequences. As used in this section, "peak period" shall be either the
				coincident peak building load period, the peak price period, the peak utility
				load period, or the peak building demand period. The following additional
				requirements apply to these measures:
1. Where credit is taken for C406.3.6,
			 service water heating energy storage, the equipment shall be provided with
			 controls that comply with ANSI/CTA 2045-B.
2. For load management measures in Sections
			 C406.3.1 through C406.3.5:
2.1. Where the
			 serving utility has a real-time demand response or pricing program, an
			 interface compliant with serving utility requirements shall be
			 installed.
2.2. Where the serving
			 utility does not have a real-time demand response or pricing program, a digital
			 input to the system to support future utility programs shall be installed and
			 building demand monitoring shall be installed and integrated into the load
			 management sequence.
2.3. All
			 equipment involved in the required load management sequence shall have controls
			 connected to a central DDC system.
Table C406.3
Load Management Measure Credits
Measure Title
Applicable Section
Occupancy Group
Group R-1
Group R-2
Group B
Group E
Group M
All Other
1. Lighting load management
C406.3.1
12
15
27
15
NA
NA
2. HVAC load management
C406.3.2
29
24
42
23
13
26
3. Automated shading
C406.3.3
NA
7
12
16
NA
NA
4. Electric energy storage
C406.3.4
41
50
126
72
37
65
5. Cooling energy storage
C406.3.5
13
10
14
19
NA
14
6. Service hot water energy storage
C406.3.6
31
248
59
8
5
70
7. Building thermal mass
C406.3.7
NA
NA
50
95
96
80
C406.3.1
Lighting load
			 management.
Automatic controls shall be capable of gradually reducing
			 general lighting power with continuous dimming in 75 percent of the building
			 area by at least 20 percent during peak demand periods. Where less than 75
			 percent, but at least 50 percent, of the building area lighting is controlled,
			 the credits from Table C406.3 shall be prorated as follows:
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EXCEPTION:
Warehouse or retail storage building areas shall be
						  permitted to achieve this credit by switching off at least 25 percent of
						  lighting power in 75 percent of the building area without dimming.
C406.3.2
HVAC load management.
Automatic controls shall:
1. Where electric
			 cooling is used, be configured to gradually increase, over a minimum of three
			 hours, the cooling setpoint by at least 3°F during the summer peak
			 periods.
2. Where electric heating
			 is used, be configured to gradually reduce, over a minimum of three hours, the
			 heating setpoint by at least 3°F during winter peak periods.
C406.3.3
Automated shading
			 load management.
Where fenestration on south and west exposures exceeds
			 20 percent of the wall area, automatic controls shall be configured to operate
			 movable exterior shading devices or dynamic glazing to reduce solar gain
			 through sunlit fenestration on southern and western exposures by at least 50
			 percent during summer peak periods.
Informative Note
:
This credit can be met by exterior roller, movable
						  blind or movable shutter shading devices; however, fixed overhang, screen or
						  shutter shading will not meet the requirement. Roller shades that reject solar
						  gain but still allow a view are allowed as long as they provide an effective 50
						  percent reduction in net solar gain (e.g., have a shading coefficient of less
						  than 0.5 for the shading material itself). Interior shading devices will not
						  meet the requirement. Electrochromatic windows that achieve 50 percent of SHGC
						  would qualify.
C406.3.4
Electric energy
			 storage.
Automatic controls shall store electricity in electric storage
			 devices during nonpeak periods and use stored energy during peak periods.
			 Electric storage devices shall have a minimum capacity of 5
			 Wh/ft2 (58 Wh/m2) of
			 gross building area. For greater storage capacity up to 15
			 Wh/ft2 (160 Wh/m2),
			 credits shall be prorated as follows:
[Installed electric storage capacity,
				Wh/ft2] × [C406.3.4 credits from Table
				C406.3]
C406.3.5
Cooling energy storage.
Automatic controls shall be capable of
			 activating ice or chilled water storage to reduce peak period electric demand.
			 Credits shown in Table C406.3 are based on storage capacity of 2 ton-hours per
			 design day ton of cooling load (2 kWh per design day kW) with a 1.15 sizing
			 factor. Credits shall be prorated for installed storage systems sized between
			 0.5 and 3.5 ton-hours per design day ton (kWh per design day kW) of cooling
			 load rounded to the nearest whole credit. The storage tank shall have no more
			 than 1.5 percent of storage capacity standby loss per day.
C406.3.6
Service hot water energy
			 storage.
To achieve this credit, where service hot water is heated by
			 electricity, automatic controls shall preheat stored service hot water before
			 the peak period and suspend electric water heating during the peak period.
			 Storage capacity shall be provided by either:
1. Preheating water above 140°F
			 (60°C) delivery temperature with at least 1.34 kWh of energy storage per kW
			 of water heating capacity. Tempering valves shall be provided at the water
			 heater delivery location.
2.
			 Providing additional heated water tank storage capacity above peak service hot
			 water demand with equivalent peak storage capacity to item 1.
C406.3.7
Building thermal
			 mass.
To achieve this credit, the building shall have both additional
			 passive interior mass and a night-flush control of the HVAC system.
1. Interior to the
building thermal
			 envelope
insulation, provide 15 pounds of passive thermal mass per
			 square foot of building floor area. Mass construction shall be in the building
			 interior and the indoor facing portion of the exterior wall, and interior floor
			 construction. Mass construction shall have mass surfaces in direct contact with
			 the air in conditioned spaces with directly attached wall board or hard surface
			 flooring allowed. Mass with carpet or furred wallboard shall not be counted
			 toward the building mass required. For integral insulated concrete block walls
			 complying with ASTM C90, only the mass of the interior face shall be counted
			 toward the building mass required.
2. When summer mode is active and indoor
			 average temperature is 5°F (3°C) or more above outdoor temperature and
			 between 10:00 p.m. and 6:00 a.m.,
automatic
night flush
			 controls shall operate outdoor air economizers at low fan speed less than 66
			 percent during the unoccupied period until the average indoor air temperature
			 falls to the occupied heating setpoint. Summer mode shall be activated when
			 outdoor air exceeds 70°F (21°C) and continues until deactivated when
			 outdoor air falls below 45°F (7°C). Another night flush strategy shall
			 be permitted where demonstrated to be effective, avoids added morning heating
			 and is
approved
by the
code official
.
Informative Note
:
The simplified night flush sequence described will
						  operate in "summer mode" below the 70°F outdoor air trigger temperature
						  down until outdoor air of 45°F is hit when the "summer mode" is deactivated
						  until the outdoor air temperature rises above 70°F again. Other strategies
						  may be implemented that cool the space below the heating setpoint and adjust
						  the morning heating setpoint to avoid morning reheating.