Design Conditions
301.1 General: The criteria of this chapter establish the design conditions upon which the minimum thermal design requirements of the building envelope and the design of the HVAC system are to be based.
301.2 Heating and Cooling: A building that is designed to be both heated and cooled shall meet the more stringent of the heating or cooling requirements as required in this Code when requirements of the exterior envelope differ.
SECTION 302 - THERMAL DESIGN PARAMETERS
302.1 Exterior Design Conditions: The heating or cooling outdoor design temperatures shall be selected from 0.6% column for winter and 0.5% column for summer from the Puget Sound Chapter of ASHRAE publication "Recommended Outdoor Design Temperatures, Washington State, ASHRAE." (See also Washington State Energy Code Manual.) **Form Equipment Sizing**
302.2 Interior Design Conditions
302.2.1 Indoor Design Temperature: Indoor design temperature shall be 70°F for heating and 78°F for cooling.
EXCEPTION: Other design temperatures may be used for equipment selection if it results in a lower energy usage.
302.2.2 Humidification: If humidification is provided during heating, it shall be designed for a maximum relative humidity of 30%. When comfort air conditioning is provided, the actual design relative humidity within the comfort envelope as defined in Standard RS-4, listed in Chapter 7, shall be selected for minimum total HVAC system energy use.
302.3 Climate Zones: All buildings shall comply with the requirements of the appropriate climate zone as defined herein.
ZONE 1: Climate Zone 1 shall include all counties not included in Climate Zone 2.
ZONE 2: Climate Zone 2 shall include: Adams, Chelan, Douglas, Ferry, Grant, Kittitas, Lincoln, Okanogan, Pend Oreille, Spokane, Stevens and Whitman counties.
SECTION 303 - MECHANICAL VENTILATION
For all Occupancies, the minimum requirements for ventilation shall comply with the Washington State Ventilation and Indoor Air Quality Code (WAC 51-13). **CAM 406**
