CEN/TC 89/WG 9 - Climatic data

2011-02-08 EMA: // final draft received in ISO/CS (see notification from 2011-02-07 in dataservice).
MINOR AMENDMENT!!!     MINOR AMENDMENT!!!     MINOR AMENDMENT!!!     MINOR AMENDMENT!!!

ISO 15927-3:2009 specifies two procedures for providing an estimate of the quantity of water likely to impact on a wall of any given orientation. It takes account of topography, local sheltering and the type of building and wall.
The first method, based on coincident hourly rainfall and wind data, defines the method of calculation of the annual average index, which influences the moisture content of an absorbent surface, such as masonry, and the spell index, which influences the likelihood of rain penetration through masonry and joints in other walling systems.
The second method, based on average wind data and a qualitative recording of the presence and intensity of rain (the present weather code for rain), defines a method for calculating the spell length during which an absorbent material such as masonry is moistened, having a 10 % probability of being exceeded in any year (commonly referred to as having a mean return period of 10 years).
ISO 15927-3:2009 provides a comparison between the two methods.
ISO 15927-3:2009 gives procedures to correct the results of both methods for topography, local sheltering and the type of building and wall.
The methods included in ISO 15927-3:2009 do not apply in mountainous areas with sheer cliffs or deep gorges, in areas in which more than 25 % of the annual rainfall comes from severe convective storms, and in areas and during periods when a significant proportion of precipitation is made up of snow or hail.

ISO 15927-2:2009 gives the definition, and specifies methods of calculation and presentation of the monthly external design climate to be used in determining the design cooling load of buildings and the design of air conditioning systems.

ISO 15927-6:2007 specifies the definition, method of computation and method of presentation of data on accumulated temperature differences, used for assessing the energy used for space heating in buildings. These are normally expressed in degree‑hours or degree-days, and such data are often referred to simply as "heating degree-hours" or "heating degree-days".
ISO 15927-6:2007 includes approximate methods for calculating accumulated temperature differences based on hourly or daily mean temperatures and for estimating monthly values to any base temperature, for use when data computed directly from meteorological air temperature records are not available.
In some countries, a threshold temperature different from the base temperature is used. ISO 15927-6:2007 does not cover this.

ISO 15927-4:2005 specifies a method for constructing a reference year of hourly values of appropriate meteorological data suitable for assessing the average annual energy for heating and cooling. Other reference years representing average conditions can be constructed for special purposes. The procedures in this part of ISO 15927-4:2005 are not suitable for constructing extreme or semi-extreme years for simulation of, for example, moisture damage or energy demand in cold years.
Meteorological instrumentation and methods of observation are not covered.

ISO 15927-5:2004 specifies the definition, method of calculation and method of presentation of the climatic data to be used in determining the design heat load for space heating in buildings. These include the winter external design air temperatures and the relevant wind speed and direction, where appropriate.
Heat loss through the ground, which also contributes to the heat load for buildings, depends on longer-term temperature changes; methods for calculating ground heat loss are given in ISO 13370.

ISO 15927-1:2003 specifies procedures for calculating and presenting the monthly means of those parameters of climatic data needed to assess some aspects of the thermal and moisture performance of buildings. Numerical values for any locations should be obtained from the meteorological service in the relevant country.
ISO 15927-1:2003 covers the following single climate variables: air temperature; atmospheric humidity; wind speed; precipitation; solar radiation; longwave radiation.
Meteorological instrumentation and methods of observation are not covered; these are specified by the World Meteorological Organisation (WMO).