(Supersedes ANSI/ASHRAE Standard ). Thermal. Environmental. Conditions for. Human Occupancy. Approved by the ASHRAE Standards Committee. See Appendix I for approval dates by the ASHRAE Standards Committee, the ASHRAE an ASHRAE Standard may be purchased from the ASHRAE Web site . This standard is in close agreement with ISO Standards and Page 1 ANSI/ASHRAE Standard R Public Review Draft Table of Contents 1.
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These requirements apply to the entire comfort zone, but wshrae be conservative for conditions near the upper temperature limits of the comfort zone and may underestimate acceptability at the lower temperature limits of the comfort zone. The radiant asymmetry 55–1992 determined at the waist level, 0.
Where the variability within a group of occupants is of the second form and is a result only of individuals freely making adjustments in clothing to suit their individual thermal preferencesit is acceptable to use a single representative average clothing insulation value for everyone in that group.
See Section 3 for definition of response time and its relation to the time constant. If 55-11992 are wearing articles of clothing not listed in the table, please enter them into the space provided below.
A occupant-controlled naturally conditioned space is where the thermal conditions of the space are primarily regulated by occupant-controlled openings. A temperature level should of course be selected to minimize the discomfort among the actual users 6. Allowable radiant temperature asymmetry for the three classes of thermal environment. All of the building systems must be designed to maintain the occupied spaces at the indoor conditions specified by one of the described evaluation methods at design conditions.
If the ensemble in question matches reasonably well with one of the ensembles in this table, then the azhrae value of I cl ashrrae be used.
ASHRAE 55 – Wikipedia
Weather based exceedence will usually be less than indicated by the exceedence percentage because other design loads will not often be concurrent. Building systems combination of mechanical systems, control systems, and thermal envelopes must be designed so that, at design conditions, they are able to maintain the space at conditions within the range specified by one of the methods in this standard.
It also added a general satisfaction survey to section 7 intended to evaluate general thermal comfort in an occupied space, bringing the standard in line with current survey-based post-occupancy evaluation POE practices.
In some situations, variations with a period not greater than 15 minutes are superimposed on variations with a longer period. See Appendix A for estimation of metabolic rates. From this definition, the commissioning team will evaluate the system’ s ability to meet and maintain the adhrae comfort level s.
However, the period may extend up to 15 minutes to average cyclic fluctuations if necessary. Any application of this standard must clearly state which of these sections is used. This asymmetry may cause local discomfort and reduce the thermal acceptability of the space. The metabolic rates associated with the activities of various individuals in a space may not be averaged awhrae find a single, average metabolic rate to be applied to that space.
Clothing insulation is the resistance to sensible heat transfer provided by a clothing ensemble expressed in units of clo, which is a unit to quantify the insulation provided by 55-992 and clothing ensembles.
Again, the method of trending must be included with this submission if it has not been provided prior to commissioning for approval. There should be at least seven points on the scale ending with “very acceptable” and “very unacceptable. These insulation levels are typical of clothing worn when the outdoor environment is warm and cool respectively. The allowable operative temperature limits in Figure 5. However, this standard may also be used to determine appropriate environmental conditions for moderately elevated activity.
However, when occupants choose to turn off the elevated air speed, these criteria apply. If any other version is used, it is the user’s responsibility to verify and document that the version used yields the same ashrea as the code in Appendix D for the conditions for which it is applied. This section specifies allowable differences between the air temperature at head level and the air temperature at ankle level. Requirements are now clearly stated and calculation procedures appear sequentially.
These values may be used in the above equation when the turbulence intensity is not measured. When occupants do not have control over the cyclical variation or drifts in indoor environmental conditions, the conditions within this section 55-1992 be met.
Determine the need to verify floor surface temperature, vertical temperature difference and radiant temperature asymmetry.
Standard 55 – Thermal Environmental Conditions for Human Occupancy
Purpose To specify the combinations of indoor thermal environmental factors and personal factors that will produce thermal environmental conditions acceptable to a majority of the occupants within the space.
However, other reasonable circumstances involving loads or malfunctions may also result in excursions. Radiant temperature asymmetry between ceiling and floor, and air and walls must be limited to reduce discomfort. The heights need to be adjusted for standing persons. The first form of variability may result in differences in the requirements for thermal comfort between the different occupants and these differences should be addressed in applying this standard.
The class of comfort must be specified by the user. Radiant asymmetry is the difference between the plane radiant temperature in opposite directions. Section 7 underwent major revisions for measuring thermal comfort in existing spaces including procedures for physical measurements and survey methods, and how to evaluate and report results.
The 551992 increase in temperature pertains to both the mean radiant temperature and the air temperature. The system input or output capacities necessary to attain the design indoor conditions at design outdoor ambient conditions should be stated in writing, as well as the full input or output capacities of the system as supplied and installed. A complete clothing ensemble may be defined using a combination of the garments listed in Table B2.
The second method is to add or subtract individual garment clo value to achieve the clothing ensemble in question.