The signing of a rental contract only takes place if there is no health risk. For this reason, there is the possibility of establishing an optimization value from the point of view of the City of Vienna in the context of a private law contract. This value is defined as the guideline.
In the case of mobile radio systems on urban objects, the operator must prove mathematically before agreeing to install a mobile radio system that the planned power density, including the existing RF services, will not exceed the optimization value.
Due to the licensing by the Federal Regulatory Authority in September 2010, regarding the expansion of the LTE mobile radio technology, the implementing provision for the approval of the construction of mobile radio systems on properties of the City of Vienna and Wiener Wohnen was revised.
For the expansion of the network, existing mobile radio sites have priority. New stations are only approved where there is no suitable infrastructure.
The basic intention of the new guideline is to undercut the optimization value of 100 mW / m² total exposure at the main emission point in the building (this is the point at which the greatest imission is to be expected with simultaneous regular residence of humans). A technically feasible and economically justifiable minimization is required regardless. This means that, taking into account the average base value at the immission site, the total exposure of 6.14 V / m (100 mW / m²) at the immission points to be considered should not be exceeded. For GSM / UMTS 10mW / m² per channel and technology must not be exceeded. Total exposure is understood to mean the interaction of the RF services acting at the main point of immission.
These are in particular: all mobile radio frequencies (GSM, UMTS, LTE, etc.), radio and television frequencies, WLAN, authorities radio - blue light organizations.
The average background level is based on practical measurement results by TÜV Austria in the city of Vienna. Basically, a value of 5 mW / m² is assumed for this background level and subtracted from the optimization value (100 mW / m²). If measurements of the background level on site give higher or lower power flux densities, these should be used.
This background level includes all fixed radio services in the frequency range from 75 MHz to 3 GHz (broadcast, DVB-T, Tetra, W-LAN, etc.), assessed at the immission point, with the exception of mobile services (GSM / UMTS / LTE). Also included are mobile radio services, the transmission of which may well be higher, but which are only relevant for a short period of time due to the movement of the source or the intermittent operation of the transmitting radio station and which make a much smaller contribution to the total immission over a period of 6 minutes.
It can be assumed that the actual background level for immission measurements will be lower in almost all cases. However, since those radio transmitters which are responsible for the major part of the immission do not generate a uniform field distribution over the area of Vienna, the background level is defined as 5 mW / m² and thus this reference value is located in the upper limit of the background field strengths obtained from the measurement series.
If necessary, this background level is checked after consultation with an accredited measuring institute.