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184.108.40.206 Direct Digital Control (DDC) Requirements
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Direct digital control shall be required as follows.
DDC shall be provided in the applications and qualifications listed in Table 220.127.116.11.1.
Table 18.104.22.168.1 DDC Applications and Qualifications
|New building||Air-handling system and all zones served by the system||Individual systems supplying more than three zones and with fan system bhp of 10 hp and larger|
|Chilled-water plant and all coils and terminal units served by the system||Individual plants supplying more than three zones and with design cooling capacity of 300,000 Btu/h and larger|
|Hot-water plant and all coils and terminal units served by the system||Individual plants supplying more than three zones and with design heating capacity of 300,000 Btu/h and larger|
|Alteration or addition||Zone terminal unit such as VAV box||Where existing zones served by the same air-handling, chilled-water, or hot-water system have DDC|
|Air-handling system or fan coil||Where existing air-handling systems and fan coils served by the same chilled- or hot-water plant have DDC|
|New air-handling system and all new zones served by the system||Individual systems with fan system bhp of 10 hp and larger and supplying more than three zones and more than 75% of zones are new|
|New or upgraded chilled-water plant||Where all chillers are new and plant design cooling capacity is 300,000 Btu/h and larger|
|New or upgraded hot-water plant||Where all boilers are new and plant design heating capacity is 300,000 Btu/h and larger|
- Monitoring zone and system demand for fan pressure, pump pressure, heating, and cooling.
- Transferring zone and system demand information from zones to air distribution system controllers and from air distribution systems to heating and cooling plant controllers.
- Automatically detecting those zones and systems that may be excessively driving the reset logic and generate an alarm or other indication to the system operator.
- Readily allowing operator removal of zones from the reset algorithm.