swfASHRAE_55_2004_Thermal_Environmental_Conditions_for_Human_Occupancy

ASHRAE Standard Project Committee 55

Cognizant TC:TC 2.1,Physiology and Human Environment

SPLS Liaison:Frank E.Jakob

WayneA Dunn,Chair* ByronWJones DipakJ ShahGai lS Brager,Vice-Chair* Joseph N Knapp PeterSimmonds*GaetanoAlfano Al ison G Kwok* JerryM Sipes*LarryG Berglund HalLevin* El iaM Sterl ing*KarlA Brown ArsenK Mel ikov BenjaminPSun*DanielR Clark BjarneW Olesen* (Chair, 1995-1998) StevenT Taylor*JosephJ Deringer* NigelA Oseland Shin-IchiTanabeCl ifford C Federspiel Nicholas B Rajkovich* RobertW Tinsley*JaapJ Hogel ing GaryRaw JornToftum*Daniel Int-Hout, I I I* (Chair, 1999-2001) David G Scheatzle* Stephen C Turner*- James E Woods

*Denotes members of voting status when the document was approved forpublication

- VanD Baxter,Chair FrankE Jakob- Davor NovoselDonaldB Bivens DavidE Knebel- DeanS Borges FrederickH KohlossPaulWCabot MerleFMcBrideCharlesW Coward, Jr MarkPModeraHughFCrowther CyrusH NasseriBrianP Dougherty GideonShavitHakimElmahdy DavidR TreeMattR Hargan ThomasH Wi l l iamsRichardD Hermans JamesE WoodsJohnFHogan RossD Montgomery,BODExO

Kent W Peterson,CO

Claire B Ramspeck,Manager of Standards

SPECIAL NOTE

ThisAmerican NationalStandard(ANS) isanationalvoluntaryconsensusstandarddeveloped undertheauspicesof theAmericanSocietyof Heating,Refrigerating andAir-Conditioning Engineers(ASHRAE)Consensus isdefined bytheAmerican National StandardsInstitute(ANSI),of which ASHRAE is a memberand which has approved this standard as an ANS,as“substantial agreement reachedby directly and material ly affected interestcategories This signifies the concurrence of more than a simple majority,but not necessari lyunanimity Consensus requires that al l views and objections be considered, and that an effort be made toward their resolution”Compl iance with this standard is voluntary unti l and unless a legal jurisdiction makes compl iance mandatorythrough legislationASHRAE obtains consensus through participation of its national and international members, associated societies, and publ icrevi ew

ASHRAE Standards are prepared by a Project Committee appointed specifical ly for the purpose of writing the Standard TheProject Committee Chairand Vice-Chair must be members of ASHRAE;whi le othercommittee members mayor may not beASHRAEmembers,al l must be technical ly qual ified in the subject area of the Standard Everyeffort is made to balance the concerned interestson al l Project Committees

The Manager of Standards of ASHRAE should be contacted for:a interpretation of the contents of this Standard,b participation in the next review of the Standard,c offering constructive criticism for improving the Standard,d permission to reprint portions of the Standard

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CONTENTS

ANSI/ASHRAE Standard 55-2004

Thermal Environmental Conditions for Human Occupancy

SECTION PAGEForeword. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

1 Purpose. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

2 Scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

3 Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

4 General Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

5 Conditions that Provide Thermal Comfort. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

6 Compl iance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 1

7 Evaluation of the Thermal Environment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

8 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

N- ormative Appendix A: Activity Levels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

Normative Appendix B: Clothing Insulation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

Informative Appendix C:Acceptable Approximation for Operative Temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Informative Appendix E:Thermal Environment Survey. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

I-nformative Appendix F: Bibl iography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

©Copyright 2004 American Society of Heating,

Refrigerating and Air-Conditioning Engineers, Inc.

1791 Tul l ieCircle NE

Atlanta,GA 30329www ashrae org

Al l rights reserved

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(This foreword is not part of this standard. It is merely 3. DEFINITIONSinformative and does not contain requirements necessaryfor conformance to the standard. It has not been pro- adaptive model:a model that relates indoor design tempera-cessed according to the ANSI requirements for a stan- tures or acceptable temperature ranges to outdoormeteorolog-dard and may contain material that has not been subject ical or climatalogical parameters.to public review or a consensus process.)air speed: the rate of air movement at a point,without regardFOREWORD to direction.

The designer may choos.

1. PURPOSE

The purpose of this standard is to specify the combina- (or density)of water vapor at the same temperature and thetions of indoor thermal environmental factors and personal same total pressure.factors that will produce thermal environmental conditionsacceptable to a majority of the occupants within the space. insulation,clothing/ensemble(Icl):the resistance to sensibleheat transfer provided by a clothing ensemble.Expressed in

2. SCOPE clounits.Note:The definitionofclothinginsulationrelatesto

person-

2.2 It is intended that all of the criteria in this standard be ble heat transfer obtained from adding an individual garmentapplied together since comfort in the indoor environment is over the nude body.Expressed in clo units.

2.4 This standard does not address such nonthermal envi- energy into heat and mechanical work by metabolic activitiesronmental factors as air quality,acoustics,and illumination or within an organism,usually expressed in terms of unit area ofother physical, chemical, or biological space contaminants the total body surface. In this standard, this rate is expressedthat may affect comfort or health. in met units.

primarily by the opening and closing of windows by the occu- a small plane element is the same as in the existing environ-p ants. ment.

lence intensity may also be expressed in percent (i.e.

point thermal sensation scale. water vaporpressure(-m

-response time(90%):the time for a measuring sensor to reach ity over an interval of time.

tion, the 90%response time equals 2.3 times the “time the instantaneous air velocity around the mean air velocity inconstant.” a frequency distribution, defined as the square root of the

step change:an incremental change in a variable.

temperature,air(ta): the temperature of the air surrounding and 1.8 m(6 ft)above the floor and more than 1.0 m(3.3 ft)the occupant. from outside walls/windows or fixed heating,ventilating,or

vap or(psdp

temp eratu rature of an imaginary black enclosure in which an occupant the space) to which it applies.would exchange the same amount of radiant heat as in the The activity and clothing ofthe occupants must be consid-

for information on body position within the imaginary enclo- ments are not met for some known set of occupants,then thesesure. occupants must be identified.

Copyright ASHRAE

The thermal environmental conditions required for to groups of occupants such as are found in classroom situa-comfort are determined according to Section 5.2 or Section 5.3 tions.of this standard.Any application of this standard must clearly Section 5.2 contains the methodology that shall be usedstate which of these sections is used.Additionally,all require- for most applications.However, the conditions required forments of the applicable section,5.2 or 5.3,must be met. thermal comfort in spaces that are naturally conditioned arenot necessarily the same as those conditions required for other

5.CONDITIONS THAT PROVIDE indoor spaces.Field experiments have shownthat innaturallyTHERMAL COMFORT conditionedspaces,where occupantshave controlofoperable

standard is used to determine the thermal environmental 5.2 Method for Determining Acceptable Thermalconditions in a space that are necessary to achieve acceptance Conditions in Occupied Spacesby a specified percentage of occupants of that space. When Section 5.2 is used to determine the requirements

There are six primary factors that must be addressed when for thermal comfort, the requirements of all subsections—defining conditions for thermal comfort.A number of other, 5.2.1,5.2.2,5.2.3,5.2.4,and 5.2.5—must be met.This stan-secondary factors affect comfort in some circumstancessix primary factors are listed below.Complete descriptions of constitutes acceptability and values of the thermal environ-these factors are presented in Section 5.4 and Appendices A ment associated with this percentage.and B. 5.2.1 Operative Temperature. For given values of

1. Metabolic rate humidity,air speed,metabolic rate,and clothing insulation,a2

3. Air temperature acceptable thermal environmental conditions or in terms of

is addressed in Section 5.2.4. 5.2.1.1 Graphical Method for Typical Indoor Envi-

The vast majority of the available thermal comfort data ronments.The method in this section may be applied topertains to sedentary or near sedentary physical activity levels spaces where the occupants have activity levels that result intypical of office work.This standard is intended primarily for metabolic rates between 1.0 met and 1.3 met and where cloth-these conditions.However, it may also be used to determine ing is worn that provides between 0.5 clo and 1.0 clo of ther-appropriate environmental conditions for moderately elevated mal insulation.See Appendix A for estimation of metabolicactivity. It does not apply to sleeping or bed rest.The body of rates and Appendix B for estimation of clothing insulation.available data does not contain significant information regard- Most office spaces fall within these limitations.ing the comfort requirements of children, the disabled,or the The range of operative temperatures presented in Figureinfirm.However,the information in this standard can often be 5.2.1.1 are for 80%occupant acceptability.This is based on aapplied to these types of occupants if it is appliedjudiciously 10%dissatisfaction criteria for general (whole body) thermal

Figure 5.2.1.1 Acceptable range of operative temperature and humidity for spaces that meet the criteria specified in Section 5.2.1.1.

interpolation between the limits for 0.5 clo and 1.0 clo,usingthe following relationships: Figure 5.2.1.2 Predicted percentage dissatisfied(PPD)as a

.

+(1.0 clo–Icl)Tmin,05clo] /0.5 clo

Tmax,Icl=[(Icl–0.5 clo)Tmax, 10 clo insulation.See Appendix A for estimation of metabolic rates

+(1.where:

to increase the upper operative temperature limit for the –2 cool

spaces where the occupants have activity levels that result in above scale.The PPD(predicted percentage of dissatisfied)average metabolic rates between 1.0 met and 2.0 met and index is related to the PMV as defined in Figure 5.2.1.2. It iswhere clothing is worn that provides 1.5 clo or less of thermal based on the assumption that people voting+2,+3,–2,or–3

is within the recommended limits specified in Table 5.2.1.2.

The PMV model is calculated with the air temperature and Figure 5.2.3 Air speed required to offset increasedmean radiant temperature in question along with the applica- temperature.-

ity. If the resulting PMV value generated by the model is -within the recommended range, the conditions are within the The indicated increase in temperature pertains to both thecomfort zone. mean radiant temperature and the air temperature.That is

Use of the PMV model in this standard is limited to air both temperatures increase by the same amount with respect tospeeds not greater than 0.20 m/s (40 fpm).Air speeds greater the starting point.When the mean radiant temperature is low -than 0.20 m/s (40 ft/min)may be used to increase the upper and the air temperature is high,elevated air speed is less effec-temperature limits of the comfort zone in certain circum- tive at increasing heat loss.Conversely,elevated air speed is

established.However, this standard allows elevated air speed Due to increased body coverage, the effect of increasedto be used to increase the maximum temperature for accept- air speed is less with higher levels of clothing insulation.Thus,ability if the affected occupants are able to control the air Figure 5.2.3 will underestimate the required air speed for

between 0.5 clo and 0.7 clo)who is engaged in near sedentary cold floor must be considered in determining conditions forphysical activity(with metabolic rates between 1.0 met and acceptable thermal comfort.Requirements for these factors

1.3 met). are specified in this section.

TABLE 5.2.4

Percentage Dissatisfied Due to Local Discomfort from Draft (DR)or Other Sources(PD)

DR

Allowable Radiant Temperature Asymmetry

W

-may be conservative for conditions near the upper temperature Figure 5.2.4.1 Local thermal discomfort caused by radiantlimits of the comfort zone and may underestimate acceptabil- asymmetry.ity at the lower temperature limits of the comfort zone.

Table 5.2.4 specifies the expected percent dissatisfied

(PD)for each source of local thermal discomfort described in comprising the ankles,feet,and legs.The requirements in thisSections 5.2.4.1 through 5.2.4.4.The criteria for all sources of section are based on sensitivity to draft in the head region withlocal thermal discomfort must be met simultaneously at the airflow from behind and may be conservative for some loca-levels specified for an environment to meet the requirements tions on the body and for some directions of airflow.of this standard. The maximum allowable air speed is specified in Figure

) ,the predicted percentage of dissatisfied occupants as a func- where

) .the skin is not covered by clothing,especially the head region For v<0.05 m/s (10 fpm),use v=0.05 m/s (10 fpm).comprising the head,neck,and shoulders and the leg region For DR>100%,use DR=100%.