PDFWAC 51-11C-40349

Section C403.4.11—DDC systems.

C403.4.11 Direct digital control systems. Direct digital control (DDC) shall be required as specified in Sections C403.4.11.1 through C403.4.11.3.
C403.4.11.1 DDC applications. DDC shall be provided in the applications and qualifications listed in Table C403.4.11.1.
C403.4.11.2 DDC controls. Where DDC is required by Section C403.4.11.1, the DDC system shall be capable of all of the following, as required to provide the system and zone control logic required in Sections C403.2, C403.5, C403.6.8 and C403.4.3:
1. Monitoring zone and system demand for fan pressure, pump pressure, heating and cooling.
2. Transferring zone and system demand information from zones to air distribution system controllers and from air distribution systems to heating and cooling plant controllers.
C403.4.11.3 DDC display. Where DDC is required by Section C403.4.11.1 for new buildings, the DDC system shall be capable of trending and graphically displaying input and output points.
Table C403.4.11.1
DDC Applications and Qualifications
Building Status
Application
Qualifications
New building
Air-handling system and all zones served by the system
All air-handling systems in buildings with building cooling capacity greater than 780,000 Btu/h
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 system(s) and fan coil(s) 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 percent 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
[Statutory Authority: RCW 19.27A.020, 19.27A.025, 19.27A.160 and chapter 19.27 RCW. WSR 19-24-040, § 51-11C-40349, filed 11/26/19, effective 7/1/20.]