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-40350 - Section C403.5-Economizers

Current through Register Vol. 24-14, July 15, 2024
C403.5
Economizers.
Air economizers shall be provided on all new cooling
			 systems including those serving computer server rooms, electronic equipment,
			 radio equipment, and telephone switchgear. Economizers shall comply with
			 Sections C403.5.1 through C403.5.5.
EXCEPTIONS:
1a. For other than Group R-2 occupancies, cooling
						  system where the supply fan is not installed outside the building thermal
						  envelope nor in a mechanical room adjacent to outdoors, and is installed in
						  conjunction with DOAS complying with Section C403.3.5 and serving only spaces
						  with year-round cooling loads from lights and equipment of less than 5 watts
						  per square foot.
1b. For Group R-2 occupancies, cooling system where
						  the supply fan is not installed outside the building thermal envelope nor in a
						  mechanical room adjacent to outdoors, and is installed in conjunction with DOAS
						  complying with Section C403.3.5, where the ERV/HRV has a minimum 68 percent
						  sensible recovery or 60 percent enthalpy recovery heating effectiveness
						  (Exception 3 of Section C403.3.5.1 is not utilized), and serving only spaces
						  with year-round cooling loads from lights and equipment of less than 5 watts
						  per square foot.
2. Unitary or packaged systems serving one zone with
						  dehumidification that affect other systems so as to increase the overall
						  building energy consumption. New humidification equipment shall comply with
						  Section C403.3.2.7.
3. Unitary or packaged systems serving one zone where
						  the cooling efficiency meets or exceeds the efficiency requirements in Table
						  C403.5
4. Equipment serving chilled beams and chilled ceiling
						  space cooling systems only which are provided with a water economizer meeting
						  the requirements of Section C403.5.4.
5. For Group R occupancies, cooling unit where the
						  supply fan is not installed outside the
building thermal
						  envelope
or in a
mechanical room
adjacent to outdoors
						  witess than 20,000 Btu/h acooling capacity less than 54,000 Btu/h provided that
						  these are high-efficiency cooling equipment with IEER, CEER, SEER, and EER
						  values more than 15 percent higher than minimum efficiencies listed in Tables
						  C403.3.2(1), C403.3.2(2), C403.3.2(4), C403.3.2(8) and C403.3.2(9) or an IPLV
						  kW/ton that is at least 15 percent loweruae1pmenttcao qualify for this
						  exception. For split systems, compliance is based on the cooling capacity of
						  individual fan coil units.
6. Equipment used to cool
Controlled Plant
						  Growth Environments
provided these are high-efficiency cooling
						  equipment with SEER, EER and IEER values a minimum of 20 percent greater than
						  the values listed in Tables C403.3.2 (1), (3), (4), and (15).
7. Equipment serving a space with year-round cooling
						  loads from lights and equipment of 5 watts per sqfoot or greaomplying with the
						  following criteria:
7.1. Equipment serving the space utilizes chilled water
						  as the cooling source; and
7.2. The chilled water plant includes a condenser heat
						  recovery system that meets the requirements of Section C403.9.5 or the building
						  and water-cooled system meets the following requirements:
7.2.1. A minimum of 90 percent (capacity-weighted) of
						  the building space heat is provided by hydronic heating water.
7.2.2. Chilled water plant includes a heat recovery
						  chiller or water-to-water heat pump capable of rejecting heat from the chilled
						  water system to the hydronic heating equipment capacity.
7.2.3. Heat recovery chillers shall have a minimum COP
						  of 7.0 when providing heating and cooling water simultaneously.
8. Water-cooled equipment served by systems meeting the
						  requirements of Section C403.9.2.4 Condenser heat recovery.
9. Equipment used to cool any dedicated server room,
						  electronic equipment room or telecom switch room provided the system complies
						  with option a, b, or c in the table below. The total cooling capacity of all
						  fan systems without economizers shall not exceed 240,000 Btu/h per building or
						  10 percent of its air economizer capacity, whichever is greater. This exception
						  shall not be used for total building performance.
10. Dedicated outdoor air systems that include energy
						  recovery as required by Section C403.7.6 but do not include mechanical
						  cooling.
11. Dedicated outdoor air systems not required by
						  Section C403.7.6 to include energy recovery that modulate the supply airflow to
						  provide only the minimum outdoor air required by Section C403.2.2.1 for
						  ventilation, exhaust air make-up, or other process air delivery.
Equipment Type
Higher Equipment
						  Efficiency
Part-Load Control
Economizer
Option a
Tables C403.3.2(1), C403.3.2(2) and C403.3.2
						  (14)a
+15%b
Required over 85,000
						  Btu/hc
None Required
Option b
Tables C403.3.2(1), C403.3.2(2) and C403.3.2
						  (14)a
+5%d
Required over 85,000
						  Btu/hc
Waterside Economizere
Option c
ASHRAE Standard 127f
+0%g
Required over 85,000
						  Btu/hc
Waterside Economizere
Notes for Exception 9:
aFor a system where all of the
				cooling equipment is subject to the AHRI standards listed in Tables
				C403.3.2(1), C403.3.2(2), and C403.3.2 (14), the system shall comply with all
				of the following (note that if the system contains any cooling equipment that
				exceeds the capacity limits in Table C403.3.2(1), C403.3.2(2), or C403.3.2(14),
				or if the system contains any cooling equipment that is not included in Table
				C403.3.2(1), C403.3.2(2), or C403.3.2(14), then the system is not allowed to
				use this option).
bThe cooling equipment shall have an EER
				value and an IPLV value that is a minimum of 15 percent greater than the value
				listed in Tables C403.3.2(1), C403.3.2(2), and C403.3.2 (14).
cFor units with a total cooling
				capacity over 85,000 Btu/h, the system shall utilize part-load capacity control
				schemes that are able to modulate to a part-load capacity of 50 percent of the
				load or less that results in the compressor operating at the same or higher EER
				at part loads than at full load (e.g., minimum of two-stages of compressor
				unloading such as cylinder unloading, two-stage scrolls, dual tandem scrolls,
				but hot gas bypass is not credited as a compressor unloading system).
dThe cooling equipment shall have
				an EER value and an IPLV value that is a minimum of 5 percent greater than the
				value listed in Tables C403.3.2(1), C403.3.2(2), and C403.3.2 (14).
eThe system shall include a water
				economizer in lieu of air economizer. Water economizers shall meet the
				requirements of C403.5.1 and C403.5.2 and be capable of providing the total
				concurrent cooling load served by the connected terminal equipment lacking
				airside economizer, at outside air temperatures of 50°F dry-bulb/45°F
				wet-bulb and below. For this calculation, all factors including solar and
				internal load shall be the same as those used for peak load calculations,
				except for the outside temperatures. The equipment shall be served by a
				dedicated condenser water system unless a nondedicated condenser water system
				exists that can provide appropriate water temperatures during hours when
				waterside economizer cooling is available.
fFor a system where all cooling
				equipment is subject to ASHRAE Standard 127.
gThe cooling equipment subject to
				the ASHRAE Standard 127 shall have an EER value and an IPLV value that is equal
				to or greater than the value listed in Tables C403.3.2(1), C403.3.2(2), and
				C403.3.2 (14) when determined in accordance with the rating conditions ASHRAE
				Standard 127 (i.e., not the rating conditionItandard 210/240 or 3460). This
				information shall be provided by an independent third party.
Table C403.5
Equipment Efficiency Performance Exception for
				Economizers
Climate Zones
Efficiency
						  Improvement
a
4C
64%
5B
59%
a If a unit is rated with an IPLV,
				IEER or SEER then to eliminate the required air or water economizer, the
				minimum cooling efficiency of the HVAC unit must be increased by the percentage
				shown. If the HVAC unit is only rated with a full load metric like EER or COP
				cooling, then these must be increased by the percentage shown.
Statutory Authority:
				  RCW
				    19.27A.020,
				  19.27A.025 and
				  chapters
				  19.27 and
				  34.05 RCW. 13-04-056, §
				  51-11C-40350, filed 2/1/13, effective
				  7/1/13.