BS 50554:2010 pdf download – Basic standard for the in-situ assessment of a broadcast site related to general public exposure to radio frequency electromagnetic fields
Simultaneous exposure to fields of different frequencies is the common case at broadcast sites and has to be taken into account during the public and worker exposure assessment. If a national or local relevant regulation treating multiple sources is available then this regulation shall be applied. If not, a threshold level has to be set, linked with the level of protection: each relevant source needs to be included to evaluate its influence.
4.6 Area to perform a detailed assessment In [2], it is stated: “(9) This recommendation … therefore applies, in particular, to relevant areas where members of the public spend significant time in relation to the effects covered by this recommendation;” Every place where the public and/or workers can access needs to be assessed. The emissions from a broadcast site only need to be taken into account within its relevant domain.
5 Assessment methodology in the relevant domain when the exposure situation changes
5.1 Introduction Change is defined as a variation in the exposure situation which has not been previously assessed.
5.2 Determination of the Threshold Distance (TD) The TD is the minimum distance out from the boundary of the controlled area at which compliance with the basic standards (EN 50413 and EN 50383) is achieved at all heights when considering emissions from the site alone. EN 50413 and EN 50383 give the methodology for determining the threshold distance using the radiation pattern of the antennas. The TD shall be determined by the broadcast operator of the highest authorized ERP value on the site. In the absence of data to carry out the required calculation, the threshold distance can be defined by using a worst case configuration of the services. An example of a simple method for estimation of the TD from a broadcast site is described in Annex A.
5.3 Area definition Assessment of the overall exposure can be made by many stakeholders. The analysis is split into three areas:
l) area A: inside the controlled area;
m) area B: outside the controlled area of the site but within the threshold distance;
n) area C: outside the threshold distance but inside the relevant domain.
In the absence of national rules, these areas are used to define the parties responsible for collating the relevant data and also for carrying out the assessment. 5.4 Assessment
5.4.1 General The stakeholder in charge of the assessment is defined in accordance with national rules (see Annex B for German and Italian examples). This responsible stakeholder may not be unique for all areas. As an example, the result of the assessment in area A, carried out by a site owner, could be an input to a telecom operator assessing areas A, B and C following a change in its equipment configuration.
5.4.2 For area A In the absence of national rules the stakeholders in charge of the assessment will be the site operator or the broadcast operator.
The site operator is responsible for gathering the data required for the assessment within area A from:
o) characteristics of services from other stakeholders;
p) worst case characteristics of services.
In accordance with national regulations, the site operator has to inform people accessing the site.
The stakeholder in charge of the assessment will use the EN 50496.
The assessment will be carried out as often as this is deemed necessary.
5.4.3 For area B
In the absence of national rules the stakeholders may be the service operator, the site operator, and local and/or national authorities. In the absence of national rules, the site operator is responsible for gathering the data required for the assessment within area B including:
q) RF data from the site (similar to the data collected for area A);
r) RF data from signals originating outside the site (to collect from national or local authorities) or the worst case characteristics of these services;
s) environment information such as building planning applications, exclusion areas following local rules, etc.;
t) measurement data (according to EN 50492) if available or make a survey, testing the areas around installations with wideband or selective measurement equipments.