Chapter 51-11C State Building Code adoption and amendment of the 2021 edition of the International Energy Conservation Code, Commercial.

C403.2.2 Ventilation and exhaust.C403.2.2.1 Ventilation. Ventilation, either natural or mechanical, shall be provided in accordance with Chapter 4 of the International Mechanical Code. Where mechanical ventilation is provided, the system shall be configured to provide no greater …

C403.2.3 Fault detection and diagnostics. New buildings with an HVAC system serving a gross conditioned floor area of 100,000 square feet (9290 m2) or larger shall include a fault detection and diagnostics (FDD) system to monitor the HVAC system's performance and automatically id…

C403.2.4 Variable flow capacity. For fan and pump motors 5.0 hp and greater including motors in or serving custom and packaged air handlers serving variable air volume fan systems, constant volume fans, heating and cooling hydronic pumping systems, pool and service water pumping …

[Statutory Authority: RCW 19.27A.020, 19.27A.025, 19.27A.160 and chapter 19.27 RCW. WSR 19-24-040, § 51-11C-40325, filed 11/26/19, effective 7/1/20. Statutory Authority: RCW 19.27A.025, 19.27A.160, and 19.27.074. WSR 16-03-072, § 51-11C-40325, filed 1/19/16, effective 7/1/16. Sta…

[Statutory Authority: RCW 19.27A.020, 19.27A.025, 19.27A.160 and chapter 19.27 RCW. WSR 19-24-040, § 51-11C-40326, filed 11/26/19, effective 7/1/20. Statutory Authority: RCW 19.27A.025, 19.27A.160, and 19.27.074. WSR 16-03-072, § 51-11C-40326, filed 1/19/16, effective 7/1/16. Sta…

[Statutory Authority: RCW 19.27A.020, 19.27A.025, 19.27A.160 and chapter 19.27 RCW. WSR 19-24-040, § 51-11C-40327, filed 11/26/19, effective 7/1/20. Statutory Authority: RCW 19.27A.025, 19.27A.160, and 19.27.074. WSR 16-03-072, § 51-11C-40327, filed 1/19/16, effective 7/1/16. Sta…

[Statutory Authority: RCW 19.27A.020, 19.27A.025, 19.27A.160 and chapter 19.27 RCW. WSR 19-24-040, § 51-11C-40328, filed 11/26/19, effective 7/1/20. Statutory Authority: RCW 19.27A.025, 19.27A.160, and 19.27.074. WSR 16-03-072, § 51-11C-40328, filed 1/19/16, effective 7/1/16. Sta…

[Statutory Authority: RCW 19.27A.020, 19.27A.025, 19.27A.160 and chapter 19.27 RCW. WSR 19-24-040, § 51-11C-40329, filed 11/26/19, effective 7/1/20. Statutory Authority: RCW 19.27A.025, 19.27A.160, and 19.27.074. WSR 16-03-072, § 51-11C-40329, filed 1/19/16, effective 7/1/16. Sta…

C403.3 Equipment selection. Heating and cooling equipment installed in mechanical systems shall be sized in accordance with Section C403.3.1 and shall not be less efficient in the use of energy than as specified in Section C403.3.2.[Statutory Authority: RCW 19.27A.020, 19.27A.025…

C403.3.1 Equipment and system sizing. The output capacity of heating and cooling equipment shall be not greater than that of the smallest available equipment size that exceeds the loads calculated in accordance with Section C403.1.2. A single piece of equipment providing both hea…

C403.3.2 HVAC equipment performance requirements. Equipment shall meet the minimum efficiency requirements of Tables C403.3.2(1) through C403.3.2(16) when tested and rated in accordance with the applicable test procedure. Plate-type liquid-to-liquid heat exchangers shall meet the…

Table C403.3.2(1)Minimum Efficiency Requirements—Electrically Operated Unitary Air Conditioners and Condensing Unitsc,dEquipment TypeSize CategoryHeating Section TypeSubcategory or Rating ConditionMinimum EfficiencyTest ProcedureaAir conditioners, air cooled< 65,000 Btu/hbAllSpli…

Table C403.3.2(2)Electrically Operated Air-Cooled Unitary Heat Pumps—Minimum Efficiency RequirementsEquipment TypeSize CategoryHeating Section TypeSubcategory or Rating ConditionMinimum EfficiencyTest ProcedureaAir cooled (cooling mode) < 65,000 Btu/hAllSplit System, three phase …

Table C403.3.2(3)Water Chilling Packages—Minimum Efficiency Requirementsa,b,e,f Size Category Path APath BTest ProcedurecEquipment TypeUnitsFLIPLV.IPFLIPLV.IPAir-cooled chillers< 150 tonsEER(Btu/Wh)≥ 10.100≥ 13.700≥ 9.700≥ 15.800 ≥ 150 tonsEER(Btu/Wh)≥ 10.100≥ 14.000≥ 9.700≥ 16.1…

Table C403.3.2(4)Electrically Operated Packaged Terminal Air Conditioners, Packaged Terminal Heat Pumps, Single-Package Vertical Air Conditioners, Single-Package Vertical Heat Pumps, Room Air Conditioners and Room Air-Conditioner Heat Pumps—Minimum Efficiency RequirementseEquipme…

Table C403.3.2(5)Warm Air Furnaces and Combination Warm Air Furnaces/Air-Conditioning Units, Warm Air Duct Furnaces and Unit Heaters—Minimum Efficiency RequirementsEquipment TypeSize Category (Input)Subcategory or Rating ConditionMinimum Efficiencyd,cTest ProcedureaWarm-air furna…

Table C403.3.2(6)Gas- and Oil-Fired Boilers—Minimum Efficiency RequirementsEquipment TypeaSubcategory or Rating ConditionSize Category (Input)Minimum EfficiencyTest ProcedureaBoilers, hot waterGas-fired< 300,000 Btu/hg,h for applications outsidethe U.S.82% AFUEDOE 10 C.F.R. 430 A…

Table C403.3.2(7)Heat Rejection Equipment—Minimum Efficiency RequirementsiEquipment TypeaTotal System Heat Rejection Capacity at Rated ConditionsSubcategory or Rating ConditionhPerformanceRequiredb,c,d,f,gTest Procedurea,ePropeller or axial fan open-circuit cooling towersAll95°F …

Table C403.3.2(8)Electrically Operated Variable Refrigerant Flow Air Conditioners—Minimum Efficiency RequirementsbEquipment TypeSize CategoryHeating Section TypeSubcategory or Rating ConditionMinimum EfficiencyTest Procedurea < 65,000 Btu/hAllVRF Multi-Split System13.0 SEER VRF A…

Table C403.3.2(9)Electrically Operated Variable Refrigerant Flow Air-to-Air and Applied Heat Pumps—Minimum Efficiency RequirementsbEquipment TypeSize CategoryHeating Section TypeSubcategory or Rating ConditionMinimum EfficiencyTest Procedurea < 65,000 Btu/hAllVRF Multi-Split Syst…

C403.3.3 Hot gas bypass limitation. Cooling systems shall not use hot gas bypass or other evaporator pressure control systems unless the system is designed with multiple steps of unloading or continuous capacity modulation. The capacity of the hot gas bypass shall be limited as i…

C403.3.4Boiler requirements.Boiler systems shall comply with Sections C403.3.4.1 through C403.3.4.5.2.C403.3.4.1 Combustion air positive shut-off. Combustion air positive shut-off shall be provided on all newly installed boiler systems as follows:1. All boiler systems with an inp…

C403.3.5 Dedicated outdoor air systems (DOAS). For buildings with occupancies as shown in Table C403.3.5, outdoor air shall be provided to each occupied space by a dedicated outdoor air system (DOAS) which delivers 100 percent outdoor air without requiring operation of the heatin…

C403.3.6 Ventilation for Group R-2 occupancy. For all Group R-2 dwelling and sleeping units, a balanced ventilation system with a heat recovery system shall provide outdoor air directly to all habitable spaces. The heat recovery system shall have a 60 percent minimum sensible rec…

C403.3.7 Hydronic system flow rate. Chilled water and condenser water piping shall be designed such that the design flow rate in each pipe segment shall not exceed the values listed in Table C403.3.7 for the appropriate total annual hours of operation. Pipe sizes for systems that…

C403.3.8 Hydronic coil selection. Hydronic coils shall comply with Sections C403.3.8.1 and C403.3.8.2.EXCEPTION:Replacement coils within existing equipment.C403.3.8.1 Chilled-water coil selection. Chilled-water cooling coils shall be selected to provide a 15°F or higher temperatu…

C403.4 HVAC system controls. HVAC systems shall be provided with controls in accordance with Sections C403.4.1 through C403.4.12 and shall be capable of and configured to implement all required control functions in this code.[Statutory Authority: RCW 19.27A.020, 19.27A.025, 19.27…

C403.4.1 Thermostatic controls. The supply of heating and cooling energy to each zone shall be controlled by individual thermostatic controls capable of responding to temperature within the zone. Controls in the same zone or in neighboring zones connected by openings larger than …

C403.4.2 Off-hour controls. For all occupancies other than Group R, each zone shall be provided with thermostatic setback controls that are controlled by either an automatic time clock or programmable control system.EXCEPTIONS:1. Zones that will be operated continuously. 2. Zones…

C403.4.3 Hydronic systems controls. The heating of fluids that have been previously mechanically cooled and the cooling of fluids that have been previously mechanically heated shall be limited in accordance with Sections C403.4.3.1 through C403.4.3.3. Hydronic heating systems com…

[Statutory Authority: RCW 19.27A.025, 19.27A.160, and 19.27.074. WSR 16-03-072, § 51-11C-403431, filed 1/19/16, effective 7/1/16. Statutory Authority: RCW 19.27A.020, 19.27A.025 and chapters 19.27 and 34.05 RCW. WSR 13-04-056, § 51-11C-403431, filed 2/1/13, effective 7/1/13.]

C403.4.4 Part load controls. Hydronic systems greater than or equal to 300,000 Btu/h (88 kW) in design output capacity supplying heated or chilled water to comfort conditioning systems shall include controls that are configured to:1. Automatically reset the supply-water temperatu…

C403.4.5 Pump isolation. Chilled water plants including more than one chiller shall be capable of and configured to reduce flow automatically through the chiller plant when a chiller is shut down and automatically shut off flow to chillers that are shut down. Chillers piped in se…

C403.4.6 Variable flow controls. Individual pumps required by this code to have variable speed control shall be controlled in one of the following manners:1. For systems having a combined pump motor horsepower less than or equal to 20 hp (15 kW) and without direct digital control…

C403.4.7 Combustion heating equipment controls. Combustion heating equipment with a capacity over 225,000 Btu/h shall have modulating or staged combustion control.EXCEPTIONS:1. Boilers. 2. Radiant heaters.C403.4.7.1 Combustion decorative vented appliance, combustion fireplace and…

C403.4.8 Group R-1 hotel/motel guestrooms. See Section C403.7.4.C403.4.9 Group R-2 and R-3 dwelling units. The primary space conditioning system within each dwelling unit shall be provided with at least one programmable thermostat for the regulation of space temperature. The ther…

C403.4.11 Direct digital control systems. Direct digital control (DDC) shall be required as specified in Sections C403.4.11.1 through C403.4.11.4.C403.4.11.1 DDC applications. DDC shall be provided in the applications and qualifications listed in Table C403.4.11.1 and for load ma…

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 oth…

C403.5.1 Integrated economizer control. Economizer systems shall be integrated with the mechanical cooling system and be configured to provide partial cooling even where additional mechanical cooling is required to provide the remainder of the cooling load. Controls shall not be …

C403.5.2 Economizer heating system impact. HVAC system design and economizer controls shall be such that economizer operation does not increase building heating energy use during normal operation.EXCEPTION:Economizers on VAV systems that cause zone level heating to increase due t…

C403.5.3 Air economizers. Air economizers shall comply with Sections C403.5.3.1 through C403.5.3.5.C403.5.3.1 Design capacity. Air economizer systems shall be configured to modulate outdoor air and return air dampers to provide up to 100 percent of the design supply air quantity …

C403.5.4 Waterside economizers. Waterside economizers shall comply with Sections C403.5.4.1 and C403.5.4.2.C403.5.4.1 Design capacity. Water economizer systems shall be configured to cool supply air by indirect evaporation and providing up to 100 percent of the expected system co…

C403.5.5 Economizer fault detection and diagnostics (FDD). Air-cooled unitary direct-expansion units with a cooling capacity of 54,000 Btu/h or greater listed in the tables in Section C403.3.2 that are equipped with an economizer in accordance with Section C403.5 shall include a …

C403.6 Requirements for mechanical systems serving multiple zones. Sections C403.6.1 through C403.6.10 shall apply to mechanical systems serving multiple zones.C403.6.1 Variable air volume (VAV) and multiple zone systems. Supply air systems serving multiple zones shall be VAV sys…

C403.6.10 High efficiency variable air volume (VAV) systems. For HVAC systems subject to the requirements of Section C403.3.5 but utilizing Exception 2 of that section, a high efficiency multiple-zone VAV system may be provided without a separate parallel DOAS when the system is …

C403.7 Ventilation and exhaust systems. In addition to other requirements of Section C403 applicable to the provisions of ventilation air or the exhaust of air, ventilation and exhaust systems shall be in accordance with Sections C403.7.1 through C403.7.8.[Statutory Authority: RC…

C403.7.1 Demand control ventilation.C403.7.1.1 Spaces requiring demand control ventilation. Demand control ventilation (DCV) shall be provided for the following:1. Spaces with ventilation provided by single-zone systems where an air economizer is provided to comply with Section C…

C403.7.2 Occupancy sensors. Classrooms, gyms, auditoriums, conference rooms, and other spaces with an occupant load greater than or equal to 25 people per 1000 square feet (93 m2) of floor area (as established in Table 403.3.1.1 of the International Mechanical Code) that are larg…

C403.7.3 Ventilation air heating control. For ventilation air units with supplemental heating capacity that operate in conjunction with zone heating and cooling systems, supplemental heating shall not warm ventilation supply air to a temperature greater than 55°F (13°C).[Statutor…

C403.7.4 Automatic control of HVAC systems serving guestrooms. In Group R-1 buildings containing more than 50 guestrooms, each guestroom shall be provided with controls complying with the provisions of Sections C403.7.4.1 and C403.7.4.2. Card key controls comply with these requir…