ASTM_D_5157_-_97_2014.pdf

Designation:D515797(Reapproved 2014)Standard Guide forStatistical Evaluation of Indoor Air Quality Models1This standard is issued under the fixed designation D5157;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This guide provides quantitative and qualitative tools forevaluation of indoor air quality(IAQ)models.These toolsinclude methods for assessing overall model performance aswell as identifying specific areas of deficiency.Guidance isalso provided in choosing data sets for model evaluation and inapplying and interpreting the evaluation tools.The focus of theguide is on end results(that is,the accuracy of indoorconcentrations predicted by a model),rather than operationaldetails such as the ease of model implementation or the timerequired for model calculations to be performed.1.2 Although IAQ models have been used for some time,there is little guidance in the technical literature on theevaluation of such models.Evaluation principles and tools inthis guide are drawn from past efforts related to outdoor airquality or meteorological models,which have objectives simi-lar to those for IAQ models and a history of evaluationliterature.(1)2Some limited experience exists in the use ofthese tools for evaluation of IAQ models.2.Referenced Documents2.1 ASTM Standards:3D1356 Terminology Relating to Sampling and Analysis ofAtmospheres3.Terminology3.1 Definitions:For definitions of terms used in thisstandard,refer to Terminology D1356.3.2 Definitions of Terms Specific to This Standard:3.2.1 IAQ model,nan equation,algorithm,or series ofequations/algorithms used to calculate average or time-varyingpollutant concentrations in one or more indoor chambers for aspecific situation.3.2.2 model bias,na systematic difference between modelpredictions and measured indoor concentrations(for example,the model prediction is generally higher than the measuredconcentration for a specific situation).3.2.3 model chamber,nan indoor airspace of definedvolume used in model calculations;IAQ models can bespecified for a single chamber or for multiple,interconnectedchambers.3.2.4 model evaluation,na series of steps through which amodel developer or user assesses a models performance forselected situations.3.2.5 model parameter,na mathematical term in an IAQmodel that must be estimated by the model developer or userbefore model calculations can be performed.3.2.6 model residual,nthe difference between an indoorconcentration predicted by an IAQ model and a representativemeasurement of the true indoor concentration;the value shouldbe stated as positive or negative.3.2.7 model validation,na series of evaluations under-taken by an agency or organization to provide a basis forendorsing a specific model(or models)for a specific applica-tion(or applications).3.2.8 pollutant concentration,nthe extent of the occur-rence of a pollutant or the parameters describing a pollutant ina defined airspace,expressed in units characteristic to thepollutant(for example,mg/m3,ppm,Bq/m3,area/m3,or colonyforming units per cubic metre).4.Significance and Use4.1 Using the tools described in this guide,an individualseeking to apply an IAQ model should be able to(1)assess theperformance of the model for a specific situation or(2)recognize or assess its advantages and limitations.4.2 This guide can also be used for identifying specific areasof model deficiency that require further development or refine-ment.5.Components of Model Evaluation5.1 The components of model evaluation include the fol-lowing:(1)stating the purpose(s)or objective(s)of theevaluation,(2)acquiring a basic understanding of the specifi-cation and underlying principles or assumptions,(3)selecting1This guide is under the jurisdiction of ASTM Committee D22 on Air Qualityand is the direct responsibility of Subcommittee D22.05 on Indoor Air.Current edition approved Sept.1,2014.Published September 2014.Originallyapproved in 1991.Last previous edition approved in 2008 as D5157 97(2008).DOI:10.1520/D5157-97R14.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 data sets as inputs to the evaluation process,and(4)selectingand using appropriate tools for assessing model performance.Just as model evaluation has multiple components,modelvalidation consists of one or more evaluations.However,model validation is beyond the scope of this document.5.1.1 Establishing Evaluation Objectives: