CC-1000_2018

Soil Gas Control Systems ANSI/AARST CC-1000 2018 in New Construction of Buildings 20 SECTION 11: HVAC EVALUATIONS REQUIRED 13 11.1 General The intended building design and mechanical ventilation systems shall be evaluated by a heating and cooling design specialist for natural and mechanically induced negative pressure in enclosed spaces with respect to: a) locations below and to the side of the exterior foundation surfaces that adjoin soil and other earthen aggregates; and b) adjoining parking garages that are not constructed with soil gas vent systems . 11.1.1 The evaluation The evaluation shall include the building design and mechanical system response to changing diurnal and seasonal outdoor temperatures that alter both: a) pressures induced by mechanical system operation; and b) natural negative pressure commonly observed in taller buildings due to unobstructed vertical air passageways such as stairwells, elevator shafts and other thermal bypasses between floors. 11.2 Controlled negative pressure The combination of HVAC design (e.g., duct balancing and air handler capacity) and compartmentalized isolation of interior airspaces shall be designed to avoid excessive negative pressure with a design goal to result in nominally neutral or positive air pressure within the enclosed spaces. Specific ocations of concern include enclosed spaces that immediately adjoin crawl spaces, slab-on-grade or basement slabs, rooms with walls that adjoin soil and other earthen aggregates, and attached garages. Exception : Enclosed spaces that are intentionally designed to be under negative pressure (e.g., bathrooms and kitchens). 11.3 Appropriate designs HVAC designs for mitigating negative pressure shall be reviewed for: compliance with ASHRAE ventilation standards 14 ; unnecessary energy consumption 15 ; and 13 For general applicability of these methods and impact on other indoor air quality issues, see “Indoor Air Quality Guide – Best Practices for Design Construction and Commissioning” published by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). www.ashrae.org 14 For further information, see ANSI/ASHRAE Standard 62.1 “Ventilation for Acceptable Indoor Air Quality” for buildings that are more than three stories tall or ANSI/ASHRAE Standard 62.2 “Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings” design capabilities to accommodate degradation to the system’s functionality that often occurs over time. 11.4 Controls Controls for mechanical equipment shall be configured and verified after building construction to consistently meet design goals across normal fluctuations in diurnal and seasonal outdoor temperatures. 11.5 Label monitors, controls and startup Control settings and fan monitors shall have a label on or in close proximity to the mechanism that describes the purpose of the control and general instructions for operation. System control settings for any mechanical equipment shall be clearly marked to indicate the settings that existed at the time design goals were achieved and verified. 11.6 Documentation of evaluations and actions A written evaluation and related actions shall be provided by the heating and cooling design specialist and included in the operation, maintenance and monitoring (OM&M) manual. 11.7 HVAC use for supplemental mitigation The design and installation of HVAC systems shall comply with ANSI/AARST RMS-MF Radon Mitigation Standards for Multifamily Buildings or ANSI/AARST RMS-LB Radon Mitigation Standards for Schools and Large Buildings , as applicable to the intended use of the building. 15 For further information, see ANSI/ASHRAE/ USGBC/IES 189.1, “Standard for the Design of High-Performance Green Buildings Except Low-Rise Residential Buildings”