Introduction to thermal comfort standards and to the proposed new version of EN ISO 7730
Jan 16, 2016
Introduction to thermal comfort standards and to
the proposed new version of EN ISO 7730
Outline
Introduction How is an ISO standard produced? ISO 9920 ergonomics of the thermal General thermal comfort Local thermal discomfort Discussion and conclusion
Introduction
The International Standards Organization (ISO) was set up in 1947 and has over 130 member countries
The aim of this paper is to provide an introduction to ISO standards concerned with thermal comfort and to describe the proposed revision of thermal comfort standard EN ISO 7730
How is an ISO standard produced
Table 1 Six-stage process to the production of an International Standard (ISO)
Six-stage process to the production of an International Standard (ISO)
How is an ISO standard produced?
ISO standards are produced by experts from participating countries according to agreed rules and a system of voting
A thermal comfort standard is proposed and supported by a document that explains the requirement
How is an ISO standard produced?
The Committee Draft (ISO CD 7730) is circulated to member countries who will circulate it within their country and provide comments and a vote
The WG will respond to comments and revise the document accordingly A Draft International Standard (ISO DIS 7730) will then be produced
ISO 7730
The PMV predicts the mean value of the votes of a large group of people on the ISO thermal sensation scale (+3=hot;+2=warm;+1=slightly warm; 0=neutral;-1=slightly cool; -2=cool; -3=cold)
ISO 7730: validity
Related to the validity of ISO 7730 is the validity of ISO 8996-metabolic rate and ISO 9920-clothing
The estimation of metabolic heat production and clothing insulation and other properties are difficult especially when considering practical dynamic contexts
ISO 7730: scope
The standard notes that deviations may occur due to ethnic and national geographic deviations and for people who are sick or disabled.It applies to healthy men and women Children are not considered
ISO 9920 ergonomics of the thermal
Environment estimation of the thermal insulation and evaporative resistance of a clothing ensemble ISO 9920 provides an extensive database of the thermal properties of clothing and garments
ISO 9920 ergonomics of the thermal
Table 2 The influence of accuracy of estimate of metabolic rate and clothing insulation on PMV and
PPD values
ISO 9920 ergonomics of the thermal
Table 3 Three categories of thermal environment: percentage of dissatisfied due to general comfort and local discomfort
General thermal comfort
Separate comfort zones for two seasons reflect the fact that people usually change clothing according to outside temperature
General thermal comfort
Table 4 Example criteria for operative temperature and mean air velocity for typical spaces
General thermal comfort
Fig.1 Air speed required to offset increased temperature.
General thermal comfort
Fig.2 Comparison of the RP-884 adaptive models predicted indoor comfort temperatures with those predicted by the PMV-model for both air-conditioned and naturally ventilated buildings
Local thermal discomfort
Local thermal discomfort may be caused by draught, high vertical temperature difference between head and ankles
Too warm or too cool a floor, or by too high a radiant temperature asymmetry Persons engaged in light sedentary activity are the most sensitive to local discomfort
Local thermal discomfort
Fig.3 Mean air velocity as a function of local air temperature and turbulence intensity for the three categories of the thermal environment
Local thermal discomfort
Fig.4 Local discomfort caused by vertical air temperature difference.
Local thermal discomfort
Fig.5 Local thermal discomfort caused by warm or cold floors.
Local thermal discomfort
Fig.6 Local thermal discomfort caused by radiant temperature asymmetry
Discussion and conclusion
Some important issues are being discussed in the current round of standard revisions.
Fulfilling the given criteria does not guarantee 100% thermal acceptability
Discussion and conclusion
the local thermal discomfort parameters like vertical air temperature differences, floor surface temperatures and radiant temperature asymmetry have mainly been studied for younger, sedentary people in general thermal comfort
Discussion and conclusion
Standards governing indoor thermal environments at the international level (International Standard Organization (ISO);European Standard Organization (CEN)), and also the national level (ASHRAE) are on a constant cycle of revision, public review,and promulgation
簡報結束
Thank you