Exposure legislation, guidelines and levels

NRPB position
Current guidelines (ICNIRP)
Base-station power
Audit of basestations

NRPB position

Biological effects that result from heating of tissue by RF energy are often referred to as "thermal" effects. The current NRPB safety standard only limits transmitted power to levels below that which would cause heating. These standards only came into effect 50 years after the problem first became apparent – 2^nd World War RADAR crews suffered cataracts and tumours. At relatively low levels of exposure to RF radiation, i.e., field intensities lower than those that would produce significant and measurable heating, the possibility of "non-thermal" biological effects exists.

Current guidelines

Note: The figures 450 and 900 microwatts/sq.cm. could be could be  expressed as 0.45 and 0.9 Watts/m²

From: Dr. Gerard Joseph Hyland, Warwick University <gjhyland@hyland.demon.co.uk>  December 01, 2000 10:49 PM

I attach a paper that I hand out at public meetings. I hope it is of some help.
Concerning your query concerning the laxity of the UK exposure limits, the following is the situation:  following the report of the Independent Expert Group on Mobile Phones, the formerly adopted NRPB values of 3300 and10,000 microwatts/square cm where replaced by those recommended by ICNIRP -namely, 450 and 900 microwatts/sq. cm.  The lowest value in Europe is that of Switzerland, which is 4.5 and 9 microwatts/sq. cm. Thus the UK ICNIRP values are 100 times LESS stringent (and 1000 times less stringent before the adoption of ICNIRP)
I hope this clarifies the issue. In Italy the limit is 10microwatts/sq.cm.

How NRPB and ICNIRP compare

Both the NRPB and ICNIRP(1998) guidelines are intended to limit whole and partial body heating. ICNIRP notes that those with potentially higher thermal sensitivity include the frail and elderly, infants and young children. The lower ICNIRP limits having a wider ‘thermal effects’ safety margin but are not for protection against any ‘non-thermal effects’.

ICNIRP Guidelines  statement on NRPB website.

Base-station power

Based on figures in The Stewart Report (see below):
For one antenna the licence permits a maximum total power in the 1800 MHz band, from 18channels of EIRP 1500W per channel, of 24,000W EIRP.
For a typical 3 channels 1800MHz band antenna with maximum power on each channel the beam would be 4,500W EIRP.
From the present power assumed in the Stewart Report based on industry (FEI 2000) figures, the beam is 3,000W EIRP. However as they note this is only due to current technical limitations and so could go up as bandwidth requirements increase.

As WAP, videophones and 3G are brought in the bandwidth needed will go up. As bandwidth is increased (i.e. more channels used) then while signal amplitude stays constant the total power increases proportionally as does radiation exposure.

The Stewart Report [4.31- 4.32] The power of a typical base-station main beam is ratio of the EIRP to the total power output is called the gain of the antenna. For a 120 sector antenna the gain is usually between about 40 and 60.
 The licence sets the maximum EIRP at 1500 W per frequency channel corresponding to a maximum total radiated power of about 30 W per channel (= EIRP/gain). It also limits the number of channels per antenna to 16 (for 1800 MHz) and 10 (for 900 MHz). However, we have been told that in practice the number of channels is typically less than 4 for 1800 MHz and 2 to 4 at 900 MHz (FEI, 2000), which would correspond to maximum radiated powers of less than 120 W and 60–120 W, respectively. Similarly, the total radiated power emitted from an antenna is generally limited by the characteristics of the equipment to somewhat under 70 W (FEI, 2000), and a figure of 60 W will be assumed in this report. It needs to be stressed that the number of channels used, and hence the total radiated power, is limited by technical rather than legal requirements, which would in fact permit significantly larger powers to be radiated.

Audit of basestations

Following the publication of the report by the Independent Expert Group on Mobile Phones the Government asked the Radiocommunications Agency (RA) to implement a national measurement programme. Initially they will be concentrating on base stations located on school sites and anticipate visiting 100 sites after which a review of the work will take place. The Government will make a decision based on those results as to whether further measurements need to be taken.

The R.A. is only undertaking measurements and is not involved in advising whether those levels are safe.

Although priority is being given to schools with mobile phone base stations on their site, forms from schools with mobile phone base stations near their site will be accepted. The deadline for registration has passed but their site says that forms will still be accepted. The registration form was available at The RA website.

The first surveys were completed in December 2000 but by 19 February 2001 only 8 surveys had been completed. 

In April 2001, FADER queried the RA about slow audit progress and asked whether, with the introduction of new telecom 3G licence systems, the early results would still be relevant after 2 years?

Reply from Nicola Barber
Customer Services Policy Officer
Radiocommunications Agency  20th April 2001

The Radiocommunications Agency (RA) is confident that the timescale we have set for completing 100 site surveys by the end of 2001 will be met.  The initial audits were carried out by 2 teams of engineers.  Training of further teams during April is taking place to enable the audit to be rolled out across the UK.

The measurements currently being taken provide results for the situation as it stands at the moment.  Until the third generation networks are rolled out RA engineers cannot produce survey results covering these frequencies.

The 100 site audit was completed on time, Audit Results on RA website

The highest value recorded by the audit was at Folkestone School for Girls where theTotal Band Exposure Quotient was approximately 1/279 of the ICNIRP maximum guideline reference level for public exposure.

While this seems good, the RA audit results site gives no information as to how the 100 sites to survey were chosen, what antenna power was in use at the time of the survey and how locations to take measurements were chosen and how far these locations were from the transmitter (only measurements for 5 locations are reported in the Folkestone School for Girls audit)?

Without more information the results tell us almost nothing, and even then we still wouldn’t know what the measurements might be in a year or two as extra transmissions are added.

The results even carry the disclaimer “It should be noted that as the radio spectrum is continually changing, these measurements can only provide information on the RF conditions for the specific location(s) at the time of the survey.”

In 2002 the RA will be carrying out a  further audit on mobile phone base stations near to school and hospital sites.  Details of how schools and hospitals can register to be included in the audit should be posted by RA shortly.

RA SITEFINDER

The 'Sitefinder' national database of mobile phone base stations and their emissions, managed by the RA on behalf of Government, provides information on all operational, externally sited, cellular radio transmitters in the United Kingdom.

http://www.sitefinder.radio.gov.uk/

At Folkestone School for Girls, Sitefinder shows two GSM transmitters, each with a transmitter power roughly 6dB below the maximum licenced power (but note that transmitted power can be lower than transmitter power).

It would be helpful if the RA Sitefinder information included the basestations National Grid Reference. Hopefully the RA will also include basestations located inside existing structures (transmitting out through openings or Perspex ‘windows’).