hVac controls guide for Plans examiners and Building inspectors
hVac controls guide for Plans examiners and Building inspectors hVac controls guide for Plans examiners and Building inspectors
Figure 7: BAS screenshot showing temperature sensors measuring zone temperaturesAdditional Detail:a) ZoningEach zone is required to have a dedicated temperature control device. If the HVAC system is designed toregulate humidity, then each zone must also have a humidity control device.Code SectionsIECCASHRAE2009: 503.2.4.1 2007: 6.4.3.1.12012: 403.2.4.1 2010: 6.4.3.1.1b) DeadbandTemperature controls for each zone shall be capable of providing a range of 5 degrees above/belowsetpoint when no heating/cooling occurs. For example, a setpoint of 70°F for heating and 75°F for coolingprovides a 5 degree deadband where no heating or cooling will occur.Code SectionsIECCASHRAE2009: 503.2.4.2 2007: 6.4.3.2, 6.4.3.1.22012: 403.2.4.2 2010: 6.4.3.2, 6.4.3.1.2c) Thermostatic setback capabilitiesSetback controls must be able to setback temperatures during unoccupied times to 55 for heating and85°F or 90°F for cooling.Code SectionsIECCASHRAE2009: 503.2.4.3.1 2007: 6.4.3.3.22012: 403.2.4.3.1 2010: 6.4.3.3.214 Control Requirements for All Systems
d) Automatic setback and shutdown capabilitiesProgrammable thermostats shall be capable of different programs for different daily occupancy schedules.They must also retain information during power outage for 10 hours and have a temporary manualoverride option.Code SectionsIECCASHRAE2009: 503.2.4.3.2 2007: 6.4.3.3.12012: 403.2.4.3.2 2010: 6.4.3.3.1e) Optimum start controlsThe system controls shall be capable of varying the start time to bring each space up to setpointimmediately prior to scheduled occupancy. This optimum start capability recognizes that the system willrequire a variable amount of time to bring zones to comfortable conditions, depending on the building’sunoccupied condition and the weather. Systems with a capacity less than 10,000 CFM may be exemptfrom this requirement.Code SectionsIECCASHRAE2009: NA 2007: 6.4.3.3.32012: 403.2.4.3.3 2010: 6.4.3.3.3f) Zone isolationWhere multiple zones are served by a common HVAC system, but will be occupied on different schedules,the system must include controls that allow the unoccupied zones to be automatically isolated. Whenisolated, the HVAC system will neither supply nor exhaust air from the unoccupied zones.Code SectionsIECCASHRAE2009: NA 2007: 6.4.3.3.42012: NA 2010: 6.4.3.3.4Supply Fan Motor ControlASHRAE 90.1-2010 introduced a new requirement for variable airflow controls in the following types ofequipment:• Air handling and fan coil units served by chilled water and having a supply fan motor larger than 5 hp.• Units serving a single zone and having direct expansion cooling capacity of more than 110,000 Btu/h.Such equipment is required to use two speed motors or variable-speed drives on the supply fan.Control Requirements for All Systems 15
- Page 2 and 3: ContentsIntroduction ..............
- Page 5 and 6: Commercial buildingControl requirem
- Page 7 and 8: Prescriptive requirementsfor Comple
- Page 9 and 10: Code Requirements andCompliance Che
- Page 11 and 12: Control Requirements for All System
- Page 13: Figure 4: Sample control sequence s
- Page 17 and 18: Figure 9: VSD installed on a supply
- Page 19 and 20: Figure 13: Motorized damperFigure 1
- Page 21 and 22: Building InspectionSuggested Compli
- Page 23 and 24: 4) The supply of outside air is red
- Page 25 and 26: ) Control strategyEconomizers must
- Page 27 and 28: 4) The supply of outside air is red
- Page 29 and 30: must be positioned well down the du
- Page 31 and 32: Figure 23: BAS screen shot indicati
- Page 33 and 34: Code SectionsIECCASHRAE2009: NA 200
- Page 35 and 36: Figure 27: Illustrated control sequ
- Page 37 and 38: Code SectionsIECCASHRAE2009: 503.4.
- Page 39: Building InspectionSuggested Compli
- Page 42 and 43: Building InspectionSuggested Compli
- Page 44 and 45: Figure 38: Sample control sequence
- Page 46: Building Technology ProgramThe U.S.
d) Automatic setback <strong>and</strong> shutdown capabilitiesProgrammable thermostats shall be capable of different programs <strong>for</strong> different daily occupancy schedules.They must also retain in<strong>for</strong>mation during power outage <strong>for</strong> 10 hours <strong>and</strong> have a temporary manualoverride option.Code SectionsIECCASHRAE2009: 503.2.4.3.2 2007: 6.4.3.3.12012: 403.2.4.3.2 2010: 6.4.3.3.1e) Optimum start <strong>controls</strong>The system <strong>controls</strong> shall be capable of varying the start time to bring each space up to setpointimmediately prior to scheduled occupancy. This optimum start capability recognizes that the system willrequire a variable amount of time to bring zones to com<strong>for</strong>table conditions, depending on the building’sunoccupied condition <strong>and</strong> the weather. Systems with a capacity less than 10,000 CFM may be exemptfrom this requirement.Code SectionsIECCASHRAE2009: NA 2007: 6.4.3.3.32012: 403.2.4.3.3 2010: 6.4.3.3.3f) Zone isolationWhere multiple zones are served by a common HVAC system, but will be occupied on different schedules,the system must include <strong>controls</strong> that allow the unoccupied zones to be automatically isolated. Whenisolated, the HVAC system will neither supply nor exhaust air from the unoccupied zones.Code SectionsIECCASHRAE2009: NA 2007: 6.4.3.3.42012: NA 2010: 6.4.3.3.4Supply Fan Motor ControlASHRAE 90.1-2010 introduced a new requirement <strong>for</strong> variable airflow <strong>controls</strong> in the following types ofequipment:• Air h<strong>and</strong>ling <strong>and</strong> fan coil units served by chilled water <strong>and</strong> having a supply fan motor larger than 5 hp.• Units serving a single zone <strong>and</strong> having direct expansion cooling capacity of more than 110,000 Btu/h.Such equipment is required to use two speed motors or variable-speed drives on the supply fan.Control Requirements <strong>for</strong> All Systems 15
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