Standard climate

Standard climates are constant artificial climatic conditions with a defined temperature and humidity and limited ranges of air pressure and flow velocity. They can be set up in clima cabinets, closets, or rooms. The standard climate 23/50 (23 °C and 50% relative humidity) is recommended. For standards, see Table 1 ( Climates ). 

In the future the Swedish formaldehyde rules may include other UF-bonded products as MDF-boards and the requirements also may be formulated as emission rates. On the behalf of the National Board of Physical Planning and Building, the Swedish National Testing Institute has performed a study on the emission from products bonded with formaldehyde based resin. The measurements have been performed in a ventilated test chamber at standardized climate in agreement within the work of the European Organization for Standardization, CEN. 16 West European countries are represented in CEN. 

Initially, Wolkoff et al. (1991) developed a testing protocol for the FLEC cell. Later, a Nordtest method for laboratory measurements was approved (Nordtest, 1995). This Nordtest method mainly deals with the FLEC as a testing device for the determination of VOCs at standard climate and using adsorbent tubes intended for analysis by GC. Trade standards describing materials sampling etc. have been developed for specific products like paints (SVEFF, 1997) and flooring materials (GBR 1992a, GBR... 

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Table 2.1 Important fibre properties in standard climate...

After the pure loading tests artificial weathering tests are also required. In these weather exposure tests strips taken in the warp and weft directions are subjected to a standard climate. The exposure time is normally 1000 hours. After this time the strengths are determined. A time acceleration factor of 10 can be achieved. In other words, after 1000 hours of artificial weathering the strength loss after 10,000 hours can be determined. Alongside this are also calculation methods for the determination of the loss of... 

After hot pressing, the bonded samples were conditioned again in standard climate. Microtome test specimens (20 pm thick) were prepared from three different... 

The creep behaviour under static shear load and standard climate conditions is assessed over a period of 335 h with small beech specimens. 

All the prepared lamellas were stored in a standard climate chamber at 20°C and 65% relative humidity (RH) for 6 months. After this time the moisture content (MC) of the specimens was different, depending on mass loss (Table 1). Groups of lamellas were then placed into different climates in order to reach a similar equilibrium MC within all the groups. The control samples were stored in a dry climate at 20°C and 44% RH, whereas the samples treated at 180°C were exposed to a standard... 

Treatment temperatures, mass loss and moisture content in a standard climate, and moisture content prior to bonding for different group of specimens... 

Group of specimens Heat treatment temperature Average mass loss (%) Average moisture content (%) in standard climate 20°C, 65% RH Average moisture content (%) prior to bonding... 

Rehabihtation systems involving structural adhesives have been used for many years in on-site repair and strengthening of timber structures. However, because they exhibit excellent initial joint strength when tested in standard climate conditions, there has not been a major concern about their service durability and reliable and reahstic accelerated ageing tests do not, therefore, currently exist [20]. 

After pressing and conditioning for at least 7 days in standard climate at 20°C and 65% relative humidity, final test samples are prepared and subjected to bending shear as shown in Fig. 7 under a climatic cycle composed of 2 parts described in Table 11. 

The open or working time is stated in the technical data sheet for the product concerned and must never be exceeded. It should also be borne in mind that the stated tack-free or skinning time is only applicable for the standard climatic conditions specified in the data sheet. At higher temperatures and/or relative humidity levels, the tack-free time is significantly shorter. 

Moisture-curing of IC-PUR adhesives is effected by climatic conditions. As an example, Fig. 72 shows the influence of humidity and temperature on the moisturecuring of SikaTack -Drive. In a standard climate (23°C/50% r.h.), the SDAT is 4 h. 

Fibers and fiber burrdles were tested for their tensile characteristics and width values. Prior to the investigations the fibers were conditioned for at least 24 hr in a standard climate at 20°C and 65% relative hurrridity according to DIN EN ISO 139. 

As a result of its hygroscopic properties, paper and board must be tested under standard climatic conditions and the samples must be conditioned in this climate for at least 4 hours before testing (sample conditioning). In ISO 187 (1990), the preferred climate for paper testing is specified as 23 °C and 50% relative humidity. In the following the most relevant test methods for paper and board testing -will be described. 

The standard climatic zones for use in pharmaceutical product stability studies are shown in Table 1. Reference to these zones and their associated storage conditions is discussed elsewhere. °... 

The results of textile tests are thus only comparable if they were determined under the same climate conditions. The expenses to ensure a stable testing climate can be considerable. As a result, depending on the clime, different standard climates were defined (DIN EN ISO 139). Many fiber properties depend more on humidity than temperature hence temperature is variable whereas air humidity is not. 

Standard climate of temperate zones Standard climate of tropical zones ... 

Standard climate conditions are often abbreviated, for example, 20/65. 

The mechanical properties are mainly measured using a tensile tester in standard climate conditions. 

The amount of water IF4 that a textile can absorb under standard climate conditions is called the water absorption capability. It is determined by weighing the... 

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