Status and New Developments in Indoor Thermal Environmental Standards

摘要

New concepts for standards on the indoor thermal environment are being proposed on the international level, with ISO (International Standard Organisation) and CEN (European Standard Organisation), and on the national level with ASHRAE (American Society of Heating, Refrigerating and Air Conditioning Engineers). Among the new developments are recommendations for acceptable thermal environments to be speci ed as classes. This allows for differences in national requirements and for buildings designs to have different quality levels. This will require, and encourage better dialog between the client (builder, owner) and the designer. There is also an ongoing discussion within the standards review committees about how people can adapt to higher indoor temperatures during summer in naturally ventilated (free running) buildings. A method for a whole year evaluation of the indoor thermal environment is also proposed.The standards will be based on requirements for general thermal comfort (PMV, Operative temperature)and local thermal discomforts (radiant temperature asymmetry, draught, vertical air temperature differences, floor surface temperatures). One critical issue is the effect of air velocity. On one hand, increased air velocity has a bene cial effect at warm temperatures, but, on the other hand, increased air velocity may result in draught sensation in cooler temperatures. Another issue is the extent to which requirements of humidity need to be included in a standard for thermal comfort. Several recent research projects dealing with adaptation, in- uence of air velocity and the effect of humidity have been the basis for increasing the usefulness and accu-racy of the standards.