ASHRAE-Standard-55 - Page 023
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range, the basis for selecting a single value within that range shall be stated. If any occupants are deemed nonrepresentative, they shall be identified along with the rationale for their exclusion. d. Describe the design comfort conditions. These conditions are specific combinations of indoor and out door factors at which occupant thermal comfort shall be evaluated. Design comfort conditions shall be chosen to cover the most challenging thermal comfort scenarios likely experienced by the occupant, including the possible impact of direct solar radiation. Each unique combination of space and representative occupant shall be evaluated at a minimum of two design comfort conditions: cooling and heating. ( Informative Note: The design comfort conditions may not align with system or room peak heating and cooling load conditions and should be considered carefully by the designer—e.g. evaluating direct beam solar on an occupant in a perimeter room during winter.) e. State the operative temperature to, including expected ranges, used in the comfort calculation for each
combination of space, representative occupant, and design comfort condition. f. When direct-beam solar radiation falls on a representative occupant, documentation shall include the method in Section 5.3.3 used for compliance and associated documentation for the chosen method. The calculation inputs, methods, and results shall be stated where applicable. g. Thermal environmental control classification level shall be documented for each unique space, indicat ing the control measure(s) for environmental factors, the means of control, and the degree to which control changes the environmental factor. h. State compliance, or lack thereof, for each combination of space, representative occupant, and design
comfort condition.
6.2.2 Section 5.3 Specific Documentation
a. State the relative humidity and average air speed Va, including expected ranges, used in the comfort cal culation for each combination of space, representative occupant, and design comfort condition. b. Local thermal discomfort shall be addressed, at a minimum, by a narrative explanation of why an effect
is not likely to exceed Section 5 limits. Where calculations are used to determine the effect of local thermal discomfort in accordance with Section 5, the calculation inputs, methods, and results shall be stated. c. Where elevated air speed with occupant control is employed to provide satisfactory thermal conditions,
documentation shall be provided to identify the method and equipment for occupant control.
6.2.3 Section 5.4 Specific Documentation
a. State compliance time period(s) for Section 5.4 applicability. ( Informative Note: This could be select
months of the year or periods of outdoor thermal conditions when a mixed-mode system changes to natural ventilation mode.) b. State prevailing mean outdoor design temperature for each compliance time period and confirmation it is
within the bounds of Section 5.4. c. Confirm that no heating or cooling system is in operation during the compliance time period(s). d. Confirm that representative occupant metabolic rates are within the bounds of Section 5.4. e. Confirm that occupants are freely able to alter their clothing as required by Section 5.4. f. State predicted operative temperature range during occupied hours for each compliance time period, considering the dynamic performance of the space, meteorological weather data, and the effects of direct solar radiation on mean radiant temperature. g. State increased air speed adjustment to upper operative temperature limit based on Table 5-12, if applicable.
Informative Note: A sample compliance form can be downloaded at www.ashrae.org/55Files (requires
Microsoft Excel [®] .
7. EVALUATION OF COMFORT IN EXISTING BUILDINGS
7.1 Introduction. Evaluation of comfort in existing buildings is not a requirement of this standard. When such evaluation is otherwise required (e.g., by code or another standard) use one of the following methods:
7.1.1 Occupant surveys using Sections 7.2.1, 7.3.1, or 7.4.1. 7.1.2 Environmental measurement using Sections 7.2.2, 7.3.2, 7.3.3, 7.3.4, or 7.4.2. 7.1.3 When using the building automation system as an adjunct to Sections 7.1.1 or 7.1.2, it shall have the characteristics described in Section 7.3.5. 7.2 Criteria for Comfort in Existing Buildings 7.2.1 Comfort Determination from Occupant Surveys. Satisfaction is directly determined from the responses of occupants using the scales and comfort limits described in Section 7.3.1.
7.2.2 Prediction of Comfort from Environmental Measurements
ANSI/ASHRAE Standard 55-2023 21