When deploying a land mobile radio communications site a number of regulations and standards must be followed but one area of compliance which may not immediately come to mind relates to Electromagnetic Field (EMF) radiation exposure.
Please note that the following information is intended for private communications site operators. Mobile carrier base stations are subject to additional requirements and regulations which are not covered in this update.
Regulation and Requirements
The Australian Standards for EMF exposure are set by the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) in the Maximum Exposure Levels to Radiofrequency Fields – 3KHz to 300GHz (Radio Protection Series No. 3) which includes:
- Basic Restrictions for exposure to Radio Frequency Fields between 3KHz and 300GHz
- Verification of compliance
- Occupational and general public exposure protection
The standard is enforced by the Australian Communications and Media Authority (ACMA) to ensure that members of the public and RF site workers are not exposed to harmful levels of EMF radiation.
For EMF compliance the ACMA divide transmitter installations into two categories, Compliance Level 1 and Compliance Level 2. Both must comply with the ARPANSA guidelines, however, only Level 2 installations are required to keep certified compliance records.
To be classified as Level 1, a transmitter installation must meet any of the following criteria:
- Is a mobile transmitter with an average total power not more than 100W
- The transmitter installation is a point-to-point link operating above 1GHz
- The average total power supplied by the transmitter is not more than 100W and each antenna fed by the transmitter is installed so that it is inaccessible to a member of the general public
- The average total equivalent isotropically radiated power (EIRP) of all antennas fed by the transmitter does not exceed 3200W in any direction and the base of the lowest antenna is at least 10m above ground level.
Transmitter installations which do not meet any of the above criteria are considered to be Level 2.
A variety of methods can be used to assess an installation’s EMF compliance including on-site measurements, ACMA guidelines and EMF simulation software. Organisations are permitted to carry out site self-assessments, however, if the ACMA perform an audit and do not agree with the provided information they will request an assessment be performed by a NATA (National Association of Testing Authorities Australia) accredited organisation.
The ACMA outline the following procedure for assessing a land mobile radio transmitter installation for EMF compliance:
- Ascertain the antenna type
Is the antenna directional (eg Yagi) or omni-directional (eg monopole)?
- Determine the antenna EIRP
If the associated frequency licence lists an EIRP this can be used otherwise the value can be calculated using the standard formula or using charts provided by the ACMA.
- Determine the distance from the antenna at which the EMR exposure limits are met
The ACMA provide resources which can be used to calculate this distance or specialised software can be used. Adequate access restrictions should be put in place to ensure that members of the public or site workers cannot enter areas where the applicable exposure limits are exceeded.
The ACMA offer a free online EME self-assessment tool which gives the region around a given antenna where the ARPANSA limits for public EMF exposure will be exceeded (known as the “public exclusion zone”). The tool covers a selection of basic antenna types and typical power levels.
More sophisticated EMF simulation software solutions are available which allow users to create 3D site models, calculate the EMF exclusion zones and automatically generate customisable compliance reports.
Would you like a better understanding on the Australian EMF Exposure Standard or how to carry out a self-assessment then contact Mike Ryan (07) 3360 4900 or via email