Review of the Potential Health Effects of Smart Water Meter Systems Used in the Thames Water Region

Transcription

1 Review of the Potential Health Effects of Smart Water Meter Systems Used in the Thames Water Region Report Reference: UC

2 WRc is an Independent Centre of Excellence for Innovation and Growth. We bring a shared purpose of discovering and delivering new and exciting solutions that enable our clients to meet the challenges of the future. We operate across the Water, Environment, Gas, Waste and Resources sectors. RESTRICTION: This report has the following limited distribution: External: Thames Water Any enquiries relating to this report should be referred to the Project Manager at the following address: WRc plc, Frankland Road, Blagrove, Swindon, Wiltshire, SN5 8YF Telephone: + 44 (0) Website: Follow Us:

3 Review of the Potential Health Effects of Smart Water Meter Systems Used in the Thames Water Region Authors: Andy Godley Senior Consultant Customer Engagement Date: Report Reference: UC Leon Rockett Senior Toxicologist Catchment Management Project Manager: Rowena Gee Project No.: Paul Rumsby Principal Toxicologist Catchment Management Client: Client Manager: Thames Water Martin Hall Rowena Gee Project Manager Catchment Management Document History Version number Purpose Issued by Quality Checks Approved by Date V1.0 Draft report issued to client for comment. Rowena Gee, Project Manager Carmen Snowdon 30/01/15 V2.0 Second draft report issued to client. Rowena Gee, Project Manager Carmen Snowdon 22/05/15 V3.0 Final report issued to client Rowena Gee, Project Manager Carmen Snowdon 01/10/15 V4.0 Final report re-issued to client with minor amendments Rowena Gee, Project Manager Mark Kowalski 14/10/15 V5.0 Final report re-issued to client with minor amendment Rowena Gee, Project Manager Rowena Gee 11/11/15 WRc plc 2015 The contents of this document are subject to copyright and all rights are reserved. No part of this document may be reproduced, stored in a retrieval system or transmitted, in any form or by any means electronic, mechanical, photocopying, recording or otherwise, without the prior written consent of WRc plc. This document has been produced by WRc plc.

4 Contents Glossary... 1 Summary Introduction Smart Meter Systems Introduction Homerider FlexNet RF emissions Meter locations Comparison of RF Emissions from Smart Meters with Other Sources Introduction Previous studies Exposure Estimates from Smart Meters Human Health Review Introduction Guideline values Report of the Independent Advisory Group on Non-Ionising Radiation Evaluation by the International Agency for Research on Cancer Verschaeve (2012) European Commission Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) (2015) Specific Reviews of Smart Meters Summary Conclusions References Appendices Appendix A Regulatory Conformance Requirements... 44

5 List of Tables Table 2.1 Homerider system radiated power levels... 9 Table 2.2 Operating frequencies and power for FlexNet system... 9 Table 2.3 Duration and occurrence of transmissions from FlexNet Table 3.1 Table 3.2 Table 3.3 Table 3.4 Table 3.5 Level of exposure from electrical devices that emit RF energy Level of exposure from electrical devices that emit RF energy (EPRI, 2011) Calculated potential exposure to RF energy from the Homerider system components Calculated potential exposure to RF energy from FlexNet smart meters Comparison of crude and refined exposure estimates for the Homerider system Table 3.6 Calculated duty cycles for the FlexNet system Table 3.7 Table 3.8 Table 4.1 Comparison of crude and refined exposure estimates for the FlexNet system in fixed network mode Comparison of crude and refined exposure estimates for the FlexNet system in AMR mode Reference Levels applicable to the Homerider and FlexNet systems Table 4.2 Comparison of Reference Levels with exposure estimates List of Figures Figure 2.1 How to recognise the Homerider System... 7 Figure 2.2 Overview of the FlexNet fixed network solution... 7 Figure 2.3 How to recognise the FlexNet system; meter and LCE... 8 Figure 3.1 Figure 3.2 Figure 3.3 Figure 3.4 Figure 3.5 Figure 3.6 Figure 3.7 Level of exposure to RF from Homerider transmitters compared with other common household devices Level of exposure to RF from FlexNet system components compared with other common household devices Comparison of calculated exposure from Homerider smart meter transmitters with and without consideration of duty cycle and reflected exposure Comparison of crude and refined exposure estimates from FlexNet SWM Low Power Radio Comparison of crude and refined exposure estimates from FlexNet LCE Low Power Radio Comparison of crude and refined exposure estimates from FlexNet LCE Wide-Area Radio Comparison of crude and refined exposure estimates from FlexNet radio base station Figure 4.1 Risk assessment process... 27

6 Glossary AGNIR AMR ARPANSA CCST COMAR DoC Duty Cycle EEG EMR EPRI ERC EU FCC HPA IARC ICNIRP IEEE ISM LCE UK independent Advisory Group on Non-ionising Radiation Automatic Meter Reading Australian Radiation Protection and Nuclear Safety Agency California Council on Science and Technology Committee on Man and Radiation Declaration of Conformity The fraction of time a smart meter is transmitting, i.e. a duty cycle of 100% would be equivalent to continuous transmission; a 1% duty cycle would be equivalent to transmitting for 1% per 24 hours (14.4 minutes/day) Electroencephalography; a test used to detect abnormalities related to electrical activity of the brain Electromagnetic Radiation US Electric Power and Research Institute European Research Council European Union US Federal Communications Commission Health Protection Agency; former name for Public Health England International Agency for Research on Cancer International Commission on Non-Ionizing Radiation Protection Institute of Electrical and Electronic Engineers Industrial, Scientific and Medical (ISM) radio bands are portions of the radio spectrum reserved internationally for industrial, scientific and medical purposes other than telecommunications Local Communication Equipment WRc plc

7 MPE NCET PG&E PHE R&TTE Directive RF SAR SWM TETRA WHO WOE Maximum Permissible Exposure; the highest power or energy density (measured in W/cm 2 or J/cm 2 ) of radiation that is considered safe ; used to limit average exposure over a given time period National Centre for Environmental Toxicology; part of the independent research consultancy, WRc Pacific Gas and Electric Company Public Health England The European Radio equipment and Telecommunications Terminal Equipment Directive Radio Frequency; radiation (part of the EM spectrum) in the range of approximately 3 khz to 300 GHz, which corresponds to the frequency of radio waves and the alternating currents which carry radio signals Specific Absorption Rate; measures the rate of energy absorption and is expressed as watts (W) per kilogram (kg) of body mass Smart Water Meter Terrestrial Trunked Radio, formerly known as Trans-European Trunked Radio: a professional mobile radio and two-way transceiver (colloquially known as a walkie talkie) specification. TETRA was specifically designed for use by government agencies, emergency services, for public safety networks, rail transport staff for train radios, transport services and the military. World Health Organization Weight-Of-Evidence; the process of considering the strengths and weaknesses of various pieces of information in reaching and supporting a conclusion WRc plc

8 Summary Thames Water is deploying smart water meters over much of its region and wishes to be proactive in addressing any customer concerns about perceived health effects from exposure to radio frequency 1 (RF) electromagnetic radiation (EMR) from these devices. Such perceived health concerns have existed for several years in relation to smart meters generally. This report, from specialists at the National Centre for Environmental Toxicology (NCET), addresses these concerns by comparing prolonged exposure from smart water meters in close proximity with RF emissions from other common household equipment, and with international guideline limit levels (see Section 4.2) established for the protection of human health. The comparison is based on the specific systems being deployed by Thames Water - the Homerider system and the FlexNet system. The conclusions of recent authoritative reviews on research studies on the effects of RF exposure on biological systems and human health are also summarised. The main effects of EMR on biological systems depend on both the power and frequency of the emissions and the distance from the source. For the lower frequencies of EMR applicable to smart meters (RF), the damage to cells and also to many ordinary materials under such conditions is determined mainly by heating effects, and thus by the radiation power. There are also heath concerns relating to low frequency pulsing effects produced by some radio systems such as DECT cordless telephones (phones). However, neither the Homerider nor the FlexNet systems produce such a pulsing effect. This review concludes that emissions from smart meters are similar to, or much less than, emissions from other household equipment. Levels of exposure are less than that which would be expected from Wi-Fi devices, and are significantly lower than the levels of exposure that may be expected from standing close to a microwave oven or using a mobile phone (handsets). Even assuming very close proximity to smart meters for extended periods, exposure is still well below the guideline limit levels set by international authoritative bodies (see Section 4) for the protection of human health. When the very short signal durations of the smart meters are taken into account, estimated levels of exposure are lower still. It is therefore reasonable to conclude that levels of exposure to RF from smart meter devices would represent a very small fraction of the total daily exposure that an individual may be expected to receive. Toxicologists within NCET have used the weight of scientific evidence (WOE) approach to evaluate the numerous studies investigating the potential effects of RF exposure on human health, mainly from mobile phones. Overall, it can be concluded that there is no evidence that the use of smart meters would have any adverse effects on human health, particularly so for the low levels of exposure involved in the Thames Water smart meter deployments. 1 The part of the electromagnetic spectrum up to 300 GHz. WRc plc

9 1. Introduction Thames Water has a programme to install smart water meters across its region over the next 15 years. This began in 2011 and in autumn 2015 moves into a second phase of deployment. This second phase rollout is the first smart water metering deployment in the UK to use fixed network infrastructure on a large scale, allowing more frequent collection of water meter readings. The programme is as follows: From 2011 to summer 2015 deployment of approximately 300,000 smart water meters using the Homerider system in automatic meter reading (AMR) mode. These meters will be read using walk-by or drive-by methods; Autumn 2015 onwards deployment of smart water meters using the FlexNet system. Data collection will be made using walk-by and drive-by AMR technology and also by fixed network as the communication technology is rolled out across the Thames Water region over the next 15 years. Smart meter deployments around the world, and the publicity around the GB energy smart meter programme in particular, have given rise to concerns about possible health effects. Thames Water wishes to be proactive in addressing such concerns, both in the interests of its customers and to meet the objectives of the smart metering strategy in managing demand. In order to address these concerns, Thames Water has asked specialists from the National Centre for Environmental Toxicology, part of the independent research consultants, WRc, to prepare a technical review of potential health issues from exposure to RF emissions from smart water meters, with specific reference to the two systems Thames Water will be using. This report considers the issues in two parts: 1. Evidence for RF exposure levels from smart meters in general is reviewed and levels of exposure from prolonged use in close proximity are compared with RF emissions from other household equipment; and 2. A review of the human health implications of RF exposure. The report includes the international standards set for RF exposure for the frequencies used by smart meters. There have been many studies, both in humans and using experimental systems, investigating the possible effects on biological systems and human health. It is beyond the scope of this report to review all these studies individually, but there have been recent authoritative reviews by the UK independent Advisory Group on Non-ionising Radiation (AGNIR) published by the Health Protection Agency, now Public Health England (PHE), and the International Agency for Research on Cancer (IARC). The conclusions of these in-depth reviews are summarised. Most of the studies are concerned with RF exposure from mobile WRc plc

10 phone use which, as will be shown, is generally very much greater than exposure from smart meters. Therefore these studies generally constitute much more extreme exposure to RF than would be observed for smart meters. In several cases throughout this report, the phrase worst-case has been used to describe a situation. This phrase is commonly used in risk assessment to describe a situation where assumptions surrounding that situation have been made, which may be considered extreme, with the intention of ensuring the protection of the most vulnerable human populations or that protection still ensues if unlikely extreme exposure does occur. This may be reflected in this report in assumptions regarding the level and duration of exposure to RF from smart meters. For example, exposure has been calculated at specific distances from the transmitter, which are worst-case. As the exposure will decrease in proportion to the square of the distance from the transmitter, the actual exposure would be significantly reduced as the person moves away from the transmitter. Therefore, if it is considered unlikely that smart meters will produce adverse health effects in these worst-case scenarios, it becomes even more unlikely that adverse health effects will be observed following more realistic exposure. WRc plc

11 2. Smart Meter Systems 2.1 Introduction Thames Water will have three smart meter arrangements running concurrently in different parts of their region. The operation of the three arrangements is described below: Homerider system in AMR mode; FlexNet system in fixed network mode; FlexNet system in AMR mode. Both the Homerider and FlexNet systems, in common with other radio equipment placed on the European Union market, must comply with relevant European Directives and Standards; these provide a regulatory framework with essential requirements concerning user health, safety, electromagnetic compatibility and radio spectrum usage. Related conformance requirements are listed in Appendix A. 2.2 Homerider The Homerider system, shown in Figure 2.1, will be used as a walk-by and drive-by system. In this system, a battery powered radio transmitter is attached to the water meter. For most of the time, the transmitter is not sending data. The receiver, which is either carried by a meter reader walking his round (walk-by) or in a vehicle (drive-by), sends out a signal instructing all the meter transmitters within range to transmit their readings. When the meter transmitter receives this instruction it returns the reading to be recorded by the receiver. Typically reading rounds are scheduled to be 6 monthly in residential areas and monthly or quarterly for larger commercial customers. WRc plc

12 Figure 2.1 How to recognise the Homerider System 2.3 FlexNet In the FlexNet system, the meter (SWM) incorporates a low power short range radio that transmits to its associated Local Communication Equipment (LCE). This is located very close to the meter itself; typically the meter and the LCE are less than 500 mm apart and each meter has its own LCE. The LCE then transmits over a long range, up to 3 km, to a radio base station. Each radio base station will receive data from many LCEs, as shown in Figure 2.2. Figure 2.2 Overview of the FlexNet fixed network solution SWM LCE Radio base station Communications between the base station and the LCE, and the LCE and the meter are two way. For areas where there is no coverage from a radio base station at the time of meter installation, the system can operate in an AMR (walk-by or drive-by) mode. In this mode, the LCE is inactive for most of the time, but the meter transmits a reading every 15 seconds. This is collected by a meter reader walking or driving past the meter with the required receiver. When a base station comes on line within range of the LCE it will automatically switch over to WRc plc

13 operate as part of the fixed network. There will be some installations where an LCE is not fitted and these meters will remain in AMR mode. A photograph of the FlexNet system is shown in Figure 2.3. Figure 2.3 How to recognise the FlexNet system; meter and LCE 2.4 RF emissions Homerider The Homerider system will operate in the 868 MHz unlicensed ISM 2 band with radiated power levels as shown in Table 2.1. As stated in Section 2.2, the Homerider will only transmit when requested by a receiver passing by in close proximity. For residential properties this is once every six months. The typical duration of the transmission is 1.6 seconds. 2 The industrial, scientific and medical (ISM) radio bands are portions of the radio spectrum reserved internationally for industrial, scientific and medical purposes other than telecommunications. WRc plc

14 Table 2.1 Homerider system radiated power levels Device 1 Minimum EIRP Maximum EIRP mw dbm mw dbm Meter Radiated power levels 3 obtained from Homerider s data sheets, expressed as both milliwatts (mw) and as the power ratio in decibels (db) referenced to one mw. The values are rounded to the nearest whole number FlexNet The operating frequencies and power levels for the FlexNet components are shown in Table 2.2. Table 2.2 Operating frequencies and power for FlexNet system FlexNet component Frequency Power (mw) Power dbm EIRP SWM Low Power Radio 433 MHz LCE Low Power Radio 433 MHz LCE Wide-Area Radio 412 MHz Radio base station 423 MHz 50, The FlexNet system can be operated in different modes to provide greater flexibility in data collection, these will be AMR and Fixed Network (AMI mode). In fixed network mode, the default setting will be for hourly readings (i.e. every 60 minutes), although a small number of commercial meters will be read at 15 minute intervals. Therefore, within this report, occurrence of transmission every 15 minutes is assumed, in order to provide the most conservative (i.e. extreme) estimates of exposure. This system can also be operated in AMR mode for areas not yet covered by a radio base station. Whilst the frequency and power levels are the same in each mode, the occurrence and duration of the transmissions varies as shown in Table Radiated power is the product of the power supplied to an antenna and the gain of that antenna compared with some standard antenna. Effective isotropic radiated power (EIRP) is the effective radiated power referred to a theoretical isotropic radiator (which radiates equally in all directions). Effective radiated power (ERP) is referred to a half-wave antenna. A half-wave dipole antenna in free space exhibits a gain in its direction of maximum radiation of 2.15dB over a theoretical isotropic radiator. WRc plc

15 FlexNet will also be using three different meters the 640, the iperl and the Meistream Plus. The meters differ in operating principle but have the same radio characteristics. Table 2.3 Duration and occurrence of transmissions from FlexNet FlexNet component Duration of transmission (ms) Occurrence of transmission Fixed network (15 minute sample rate) SWM Low Power Radio 11 ms Every 15 minutes LCE Low Power Radio (LCE to SWM) <11 ms Very infrequently when SWM is reconfigured* LCE Wide-Area Radio (LCE to base station) 107 ms 24/day Radio base station 166 ms 167/hour AMR mode SWM Low Power Radio <3 ms Every 15 seconds LCE Wide-Area Radio (where installed) 107 ms Occasional typically 1/day * Assumed to be once per day. 2.5 Meter locations For both systems, meters will be located either internally (e.g. under the kitchen sink) or externally in boundary boxes, usually in the public highway (footpath). It is expected that approximately 65% of installations across the Thames region will be external. The boundary box lids will be plastic and therefore effectively transparent to radio waves. In external installations for the Homerider system, the meter transmitter will be located in the base of the boundary box. Anyone in the immediate vicinity of a boundary box will be exposed to power levels significantly less than those shown in Table 2.1 because of propagation losses, i.e. due to distance 4 and attenuation through the surrounding ground. It is likely that the power levels directly above the boundary box will also be significantly attenuated because of the antenna vertical radiation pattern. In external installations for the FlexNet system, the meter transmitter will be at the base of the boundary box and the LCE will be just beneath the lid. Therefore, the propagation losses will be less from the LCE than from the meter. 4 For example, the Free Space Path Loss (FSPL) over 1 m at 868 MHz = ~31 db WRc plc

16 3. Comparison of RF Emissions from Smart Meters with Other Sources 3.1 Introduction There are many sources of RF energy to which an individual may be exposed every day, including mobile phones, smartphones tablets, computers etc. using 2G, 3G and 4G telephone networks, DECT cordless phones, Bluetooth and Wi-Fi devices, microwave ovens and more. Many of these devices, which are mostly readily accepted within the home, operate at frequencies close to those used by smart meters but produce emissions at higher power levels and for significantly longer periods. Therefore, a comparison of the measured exposure to these devices with estimates of prolonged exposure in close proximity to the Homerider and FlexNet system components can provide a context for assessing the health risks. 3.2 Previous studies A number of studies have been carried out, comparing emissions from smart meters with those from other sources. Two such representative studies are discussed below Pacific Gas and Electric Company (PG&E) Review The Pacific Gas and Electric Company (PG&E) in the USA has published measurement data for the levels of exposure from smart meters compared with other common devices found in the home (PG&E, 2013). These exposure values, expressed as relative power density in microwatts per square centimetre, are presented in Table 3.1. The results are from a study by Richard Tell Associates, Inc., a scientific consulting business focused on electromagnetic field exposure assessment, compliance with applicable standards and regulations on radio frequency and power frequency fields. The data indicate that at a distance of approximately 30 cm from an electricity smart meter, the level of exposure is similar to, but less than the exposure from a microwave oven at a distance of 1 metre, and is substantially less than the exposure from a mobile phone held next to the head. WRc plc

17 Table 3.1 Level of exposure from electrical devices that emit RF energy Device Relative power density (µw/cm²) Gas SmartMeter at a distance of 1 foot (~31 cm) Electricity SmartMeter at a distance of 10 feet (~3 metres) 0.1 Electricity SmartMeter at a distance of 1 foot (~31 cm) 8.8 Microwave oven at a distance of 1 metre 10 Wi-Fi LAN/access points/routers, laptop computers, (maximum ~1 metre for laptops, 2-5 metres for access points) Mobile phone (at head) Mobile radio (Walkie-Talkie) (at head) Electric Power and Research Review A review by the US Electric Power and Research Institute (EPRI) in 2011 compared the level of exposure to a smart meter (operating at frequencies of 900 and 2400 MHz with common sources of radio frequency energy (EPRI, 2011a). This review provides significantly more detail on the conditions of exposure to each of these sources, however, a similar pattern is observed in the relative levels of exposure between smart meters and other devices. Table 3.2 Level of exposure from electrical devices that emit RF energy (EPRI, 2011) Device Frequency (MHz) Details Exposure level (µw/cm²) Smart meter at a distance of 3 feet (~91 cm) Smart meter at a distance of 10 feet (~3 metres) 900 and 2400 During transmission. Localised but nonuniform spatial characteristic 900 and 2400 During transmission. Localised but nonuniform spatial characteristic 0.1 (250 mw, 1% duty cycle 5 ) 2 (1W, 5% duty cycle) (250 mw, 1% duty cycle) 0.2 (1W, 5% duty cycle) 5 A duty cycle is the fraction of time a smart meter is transmitting, i.e. a duty cycle of 100% would be equivalent to continuous transmission; a 1% duty cycle would be equivalent to transmitting for 1% per 24 hours (14.4 minutes/day). WRc plc

18 Device Frequency (MHz) Details Exposure level (µw/cm²) Mobile phone (at head) Mobile phone base station Microwave oven at a distance of 2 inches (~5 cm) Microwave oven at a distance of 2 feet (~61 cm) Wi-Fi wireless routers and similar home devices at a distance of 3 feet (~91 cm) 900 and 1800 During call. Highly localised spatial characteristic 900 and 1800 Constant transmission. Relatively uniform spatial characteristic 2450 During use. Localised but nonuniform spatial characteristic 2450 During use. Localised but nonuniform spatial characteristic Constant use. Localised but nonuniform spatial characteristic ~ (router) (PC adapter) Radio and television Wide spectrum Constant transmission. 1 (highest 1% of broadcasts (significant Relatively uniform spatial population) distance from the source in most cases) characteristic (50% of population) 3.3 Exposure Estimates from Smart Meters The following sections detail the exposure estimates from the two smart meter systems employed by Thames Water. The initial estimates, henceforth referred to as Crude Exposure Estimates are based on the assumption that the smart meter is in continuous operation. As such, these values significantly over-estimate real exposure, where smart meters are only in operation for a fraction of the day. More realistic estimates are provided in Section 3.3.2, henceforth referred to as Refined Exposure Estimates. These values take into account the amount of time the smart meter is in operation throughout the day (the duty cycle ), as well as any reflected exposure that may occur as a result of RF emission bouncing off solid ground Calculation of Exposure from Smart Meters (Crude Exposure Estimates) According to EPRI (EPRI, 2011b), a conservative estimate of the potential exposure to radio frequency energy from a smart meter can be calculated by the following formula: WRc plc

19 Where: S is the estimated exposure (mw/cm²) EIRP is the maximum power radiated by a theoretical isotropic antenna (mw) R is the distance from the transmitter antenna (cm) It should be noted that EPRI (EPRI, 2011b) reported that this formula produced calculations of exposure 2-3 times greater than levels of exposure measured from the use of smart meters. Therefore, values derived using this approach will represent significant over-estimates of exposure to the systems in use by Thames Water. The Homerider System The Homerider smart meter transmitter operates in the 868 MHz band, close to frequencies used by other smart meter devices described above and devices that are likely to already be present in the home such as mobile phones. The Homerider smart meter transmitter has a power output of 25 mw EIRP; therefore, assuming distances of 30 and 100 cm, calculations of potential exposure to radio frequency energy are as shown in Table 3.3. As stated above, this formula produced calculations of exposure 2-3 times greater than levels of exposure measured from the use of smart meters. Therefore, the values shown in Table 3.3 are likely to represent significant over-estimates of exposure to the Homerider system. Additionally, the Homerider smart meter transmitter used in walk-by and drive-by mode only transmits for approximately 1.6 seconds when it is woken up by the receiver, typically once a month or once a quarter for larger commercial customers and once every 6 months for household customers. For household customers, this is equivalent to a duty cycle of 0.002% 6 for days when the meter is being read. Therefore, by considering this to be a continuous exposure would be a highly conservative worst-case scenario. 6 There are 60 seconds in a minute, 60 minutes in an hour and 24 hours in a day. Therefore, there are a total of seconds in a day. 1.6 seconds per day accounts for 0.002% of the total number of seconds per day (i.e. ) WRc plc

20 Table 3.3 Calculated potential exposure to RF energy from the Homerider system components Homerider device Distance from smart meter (cm) Calculated potential exposure (µw/cm²) 7 Meter transmitter Meter transmitter A comparison of these data with the levels of exposure from the conservative calculations of exposure to the Homerider smart meter transmitter and other devices reported in the literature is presented in Figure 3.1 (note that the scale on this graph is logarithmic). The conservative calculations for exposure levels from the Homerider components are shown in green, measured values from other smart meter devices are represented in red and other RF devices to which a member of the public may be exposed are represented in blue. As shown in Figure 3.1, even assuming extreme conditions, levels of exposure to RF from the Homerider transmitters are similar to those from other smart meters. Levels of exposure are also less than that which would be expected from Wi-Fi routers, and are significantly lower than the levels of exposure that may be expected by standing next to a microwave oven or using a mobile phone. 7 Calculated using the formula: WRc plc

21 Figure 3.1 Level of exposure to RF from Homerider transmitters compared with other common household devices WRc plc

22 The FlexNet systems The FlexNet smart meter transmitter operates at frequencies of 412 and 433 MHz. The smart meter transmitter and the LCE each have a power output of 10 mw and 25 dbm (calculated to be 316 mw, assuming no gain); therefore, assuming distances of 30 and 100 cm, calculations of potential exposure to radio frequency energy are as shown in Table 3.4. Similarly, the FlexNet radio base station has a power output of 47 dbm. The information provided indicates that these base stations will be installed on towers of similar height to mobile phone masts. Mobile phone masts can generally be installed at a height of up to 15 metres without planning permission, therefore, it has been assumed in this report that the radio base station will also be installed at a height of 15 metres. An assumption of a 2 m tall adult and a base station that is primarily transmitting downwards represents a worst-case scenario of a distance of 13 metres from the head. Calculations of potential exposure to radio frequency energy from the base station are also provided in Table 3.4. As stated above, this formula produced calculations of exposure 2-3 times greater than levels of exposure measured from the use of smart meters. Therefore, the values shown in the table are likely to represent significant over-estimates of exposure to the FlexNet system. Additionally, the FlexNet system will only be transmitting for several milliseconds throughout the day (see Table 3.6). Therefore, by considering this to be a continuous exposure would be a highly conservative worst-case scenario. Table 3.4 Calculated potential exposure to RF energy from FlexNet smart meters FlexNet device Distance from smart meter or base station (cm) Calculated potential exposure (µw/cm²) 8 SWM Low Power Radio SWM Low Power Radio LCE Low Power Radio LCE Low Power Radio LCE Wide-Area Radio LCE Wide-Area Radio Radio base station Calculated using the formula: WRc plc

23 A comparison of these data with the levels of exposure from the conservative calculations of exposure to the FlexNet system and other devices reported in the literature is presented in Figure 3.3 (note that the scale on this graph is logarithmic). The conservative calculations for exposure levels from the FlexNet system are shown in green, measured values from other smart meter devices are represented in red and other RF devices to which a member of the public may be exposed are represented in blue. As shown in Figure 3.2, even assuming extreme conditions, levels of exposure to RF from the FlexNet smart meters are similar to those from other smart meters, although levels from the LCE Wide-Area Radio are closer to those of Wi-Fi routers and the minimum power density of mobile phones. WRc plc

24 Figure 3.2 Level of exposure to RF from FlexNet system components compared with other common household devices WRc plc

25 3.3.2 Consideration of duration of exposure and reflected exposure (Refined Exposure Estimates) In 2010, EPRI also published a review (EPRI, 2010) of a specific smart meter that included consideration of the duty cycle and reflected exposure using the following formula: Where: S is the estimated exposure (W/m²) Pt is the maximum transmitter output power (W) Gmax is the maximum possible antenna gain (dimensionless) δ is the duty cycle of the transmitter Γ is a factor accounting for possible in-phase ground reflections. A value of 60% has been recommended by the FCC, which is equivalent to an enhancement factor of (1.6)² or 2.56 R is the distance from the transmitter (m) The Homerider system Application of this formula to the Homerider smart meter transmitter, under the conditions stated above, results in the calculated exposure levels shown in Table 3.5 and Figure 3.3. Consideration of these additional factors results in significant reductions in the level of exposure due to the very short duty cycles for the smart meter. As such, it is reasonable to conclude that levels of exposure to RF from smart meter devices would represent a small fraction of the total daily exposure to RF that an individual may be expected to receive. WRc plc

26 Table 3.5 Comparison of crude and refined exposure estimates for the Homerider system Homerider device Distance from smart meter (cm) Crude exposure estimate (µw/cm²) Refined exposure estimate (µw/cm²) 910 Meter transmitter Meter transmitter Figure 3.3 Comparison of calculated exposure from Homerider smart meter transmitters with and without consideration of duty cycle and reflected exposure The FlexNet system The calculated duty cycles for each of the FlexNet components in their various operational modes are provided in Table 3.6. It should be noted that it is intended that this system will operate in AMR mode. Application of the formula described above to the FlexNet system (and assuming no gain, as none is reported in the provided documentation) results in the calculated exposure levels 9 10 Estimate considers duty cycle of the system and reflected exposure. Calculated using the formula: WRc plc

27 shown in Figure 3.4, Figure 3.5, Figure 3.6 and Figure 3.7. Consideration of these additional factors results in significant reductions in the level of exposure due to the very short duty cycles for both the smart meter and the base station. As such, it is reasonable to conclude that levels of exposure to RF from smart meter devices would represent a small fraction of the total daily exposure to RF that an individual may be expected to receive. Table 3.6 Calculated duty cycles for the FlexNet system FlexNet component Duration of transmission (ms) Occurrence of transmission Daily transmission time (s) Duty cycle (%) 11 Fixed network (15 minute sample rate) SWM Low Power Radio 11 ms Every 15 minutes LCE Low Power Very infrequently Radio <11 ms when SWM is (LCE to SWM) reconfigured* LCE Wide-Area Radio (LCE to base station) Radio base station 107 ms 24/day ms 167/hour AMR mode SWM Low Power Radio <3 ms Every 15 seconds LCE Wide-Area Radio (where installed) 107 ms Occasional typically 1/day * Assumed to be once per day. 11 WRc plc

28 Table 3.7 Comparison of crude and refined exposure estimates for the FlexNet system in fixed network mode FlexNet device Distance from smart meter or base station (cm) Crude exposure estimate (µw/cm²) Refined exposure estimate 12 (µw/cm²) SWM Low Power Radio SWM Low Power Radio LCE Low Power Radio LCE Low Power Radio LCE Wide-Area Radio LCE Wide-Area Radio Radio base station Table 3.8 Comparison of crude and refined exposure estimates for the FlexNet system in AMR mode FlexNet device Distance from smart meter or base station (cm) Crude exposure estimate (µw/cm²) Refined exposure estimate 13 (µw/cm²) SWM Low Power Radio SWM Low Power Radio LCE Low Power Radio LCE Low Power Radio LCE Wide-Area Radio LCE Wide-Area Radio Radio base station Estimate considers duty cycle of the system and reflected exposure. Estimate considers duty cycle of the system and reflected exposure. WRc plc

29 Figure 3.4 Comparison of crude and refined exposure estimates from FlexNet SWM Low Power Radio Figure 3.5 Comparison of crude and refined exposure estimates from FlexNet LCE Low Power Radio WRc plc

30 Figure 3.6 Comparison of crude and refined exposure estimates from FlexNet LCE Wide-Area Radio Figure 3.7 Comparison of crude and refined exposure estimates from FlexNet radio base station WRc plc

31 3.3.3 Pulsing effects In addition to the thermal effects of EMR, some interest groups have expressed concerns about the biological effects of very low-frequency pulsing produced by some radio systems, suggesting that TETRA professional mobile radio may produce adverse health effects, both as a result of the frequency of operation and from these pulsing effects. However, there is no strong evidence to support these conclusions. Cordless phones based on the DECT standard are now widely used in the home. DECT is based on Time Division Duplex (TDD) and Time Division Multiple Access (TDMA) with 10 RF carriers in the MHz band, with peak power of 250 mw. During use, DECT devices emit 400 µs bursts every 10 ms, resulting in an average power of 10 mw, which is approximately 10 times smaller than the emissions from a mobile telephone. Whilst not making a call, DECT devices transmit 80 µs pulses every 10 ms, resulting in an average power of 2 Mw (HPA, 2012). Maximum electric field strengths are reported to be approximately 1% of the ICNIRP reference level at a distance of 1 metre and 0.01% of the reference level in far-field conditions (HPA, 2012). Emissions from the smart meters are much simpler, consisting of infrequent, single short transmissions. As a result, there is no equivalent pulsing effect for these systems Summary There are many sources of RF energy to which an individual may be exposed every day, including mobile phones, microwave ovens, Wi-Fi devices and cordless phones. Many of these operate on similar frequencies to smart meters but with significantly higher power and/or for a much longer duration. Highly conservative calculations of exposure to RF from the smart meter systems have been made, which have been compared with measured levels of RF exposure from other smart meter devices and other RF-emitting devices that may be found in the home. Even assuming unrealistic or extreme conditions with prolonged exposure in close proximity to the smart meter, levels of exposure to RF from the both the Homerider and the FlexNet smart meter transmitters and FlexNet base station are similar to those from other smart meters. Levels of exposure are less than that which would be expected from Wi-Fi devices, and are significantly lower than the levels of exposure that may be expected from standing close to a microwave oven or using a mobile phone. When the very short signal durations of the smart meters are taken into account, estimated levels of exposure are even lower. It is therefore reasonable to conclude that levels of exposure to RF from smart meter devices would represent a very small fraction of the total daily exposure that an individual may be expected to receive. WRc plc

32 4. Human Health Review 4.1 Introduction Risk Assessment The risk assessment process used by the toxicologists in the NCET team to conduct the human health review of smart meters is composed of several stages as illustrated in Figure 4.1 and described below. Figure 4.1 Risk assessment process Hazard Identification and Characterisation These stages involve the identification of the hazard posed by potentially toxic materials, be they chemical or radiation, etc. This is usually defined in terms of its target organ toxicity, together with the amount needed to cause that hazard, i.e. the dose response. There have been many 100s of studies in cells, experimental animals and humans, which have investigated the potential hazard which might be posed by RF. Exposure Assessment This stage involves an actual, or often estimated, exposure of a receptor, in this case a human adult or perhaps child or infant (including a determination of which is most susceptible) to the hazardous material. WRc plc

33 Risk Characterisation This stage involves the comparison of a level of exposure which would potentially have no harmful effect on human health (derived from hazard characterisation; a safe level) with the estimated or actual exposure concentration. In the case of RF, these safe levels are guidelines which have been derived by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the US Federal Communications Commission (FCC), and are described below. Exposure, either measured or estimated, above the safe level would lead to concern about human health from that level of exposure Scientific Method for Reviewing Studies There have been a large number of studies on the human health effects of RF, from cellular systems (in vitro assays) to large-scale epidemiological studies looking at the effects of instruments and processes emitting RF on the health of the public and workers. These studies involve the examination of different health endpoints and a range of different RF exposures. This being the case, it is not valid to reach conclusions on possible effects from the results of single studies. The scientific weight-of-evidence (WOE) approach is used here to examine the quality and results of all the studies in a particular field and if they point to a consistent effect, this will be accepted by the scientific community. Particularly since the use of cellular mobile phones became widespread, there have been many 100s of studies measuring exposure to RF in all types of biological systems. It is beyond the scope of this report to assess the results of all these studies. Therefore, it is appropriate to locate reviews by authoritative bodies which are current and represent the situation in the UK. In April 2012 the UK Health Protection Agency s (HPA), now Public Health England (PHE) Radiation, Chemical and Environmental Hazards Division published a review entitled Health Effects from Radiofrequency Electromagnetic Fields (HPA, 2012). This was an updated review building on one first published in 2003 and was the Report of the Independent Advisory Group on Non-Ionising Radiation (AGNIR), which consisted of eight experts whose knowledge covered all aspects of human health, together with ancillary staff. This report, being the most recent relevant review by independent UK experts, forms the basis for assessing the effects of RF on human health. The report covered all sources of RF exposure including broadcasting, industrial applications and wireless telecommunications (including smart meters). As smart metering is a relatively new technology, there are few direct studies; however, there have been a number of reviews and these will be considered. As has been shown previously, radiation emitted from mobile phones is at a similar frequency to smart meters but with much longer exposure times and a much shorter distance (next to the head), and so the human health studies on mobile phones and their RF, might be considered a worst-case scenario for smart meter exposure. WRc plc

34 The International Agency for Research on Cancer (IARC) is an organisation located in France and part of the World Health Organization (WHO) which has also recently reviewed RF and assessed its potential for carcinogenicity and associated toxicities (IARC, 2013). Its review of the evidence for toxicity is also summarised in this report. The recent review by Verschaeve (2012) brought together the results of 33 reviews of the literature published between 2009 and Guideline values International Commission on Non-Ionizing Radiation Protection In 1998, the International Commission on Non-Ionizing Radiation Protection (ICNIRP) developed guidelines for limiting exposure to electromagnetic, electric and magnetic fields up to 300 GHz (ICNIRP, 1998). These guidelines were intended to provide protection against adverse health effects, considering all the studies conducted on biological systems, exposed human populations and dosimetry of electric and magnetic fields. The specific absorption rate (SAR) measures the rate of energy absorption and is expressed as watts (W) per kilogram (kg) of body mass. The guidelines set Basic Restrictions for the assumed SAR at the specific emission frequency and the maximum (received) power density permissible. The more recent studies were reviewed in 2010 and the guidelines restated (ICNIRP, 2009). These guidelines are the central pillar of advice on RF field exposure from the HPA (HPA, 2012). They are also recognised internationally and are more precautionary than the FCC values outlined below. Therefore, these are the most appropriate guidelines to use when assessing the safety of smart meters in the UK. ICNIRP set Basic Restrictions for general health exposure and these must not be exceeded to ensure compliance for frequencies up to 10 GHz. The restriction that provides adequate protection for occupational exposure: Whole body average Specific Absorption Rate (SAR): 0.4 W/kg An addition safety factor of 5 has been introduced for exposure of the general public: Whole body average Specific Absorption Rate (SAR): 0.08 W/kg ICNIRP have also used these basic restrictions together with mathematical modelling and experimental data to derive Reference Levels to provide practical exposure assessment to determine whether Basic Restrictions are likely to be exceeded. For exposure to workers and the general public, these Reference Levels are given as power levels (equivalent plane wave power densities). According to the ICNIRP Guidelines, the Reference Level for general public exposure is ƒ/200 (ƒ is frequency between MHz). WRc plc

35 Therefore, for RF emitted from devices operating at 868 MHz (including the Homerider) and MHz (the FlexNet system), the Reference Levels for general public exposure, as derived from the Guidelines, are as shown in Table 4.1. Table 4.1 Reference Levels applicable to the Homerider and FlexNet systems Component Frequency Derivation of Reference Level (MHz) Reference Level W/m 2 µw/cm 2 Homerider system / FlexNet system SWM and LCE Low Power Radio LCE Wide-Area Radio / / Radio base station / The Reference Levels in Table 4.1 are guideline Reference Levels, and if power densities are exceeded then further investigation can be instigated to demonstrate compliances with Basic Restrictions. Comparison of these Reference Levels with the estimated power densities (exposure estimates) derived from scenarios of use, as shown in Table 3.5 (Homerider), Table 3.7 (FlexNet system in fixed network mode) and Table 3.8 (FlexNet system in AMR mode), indicates that all levels of exposure are below the Reference Levels. This is highlighted by Table 4.2 which shows that even the most conservative of the estimates (crude exposure estimates, assuming a distance of 30 cm) indicate exposure below the Reference Levels. The refined exposure estimates, accounting for duration of exposure and reflected exposure, are even further below these Levels. Table 4.2 Comparison of Reference Levels with exposure estimates Component Reference Level (µw/cm 2 ) Exposure estimate (µw/cm²) 14 Homerider system FlexNet system SWM and LCE Low Power Radio LCE Wide-Area Radio Radio base station Based on the crude exposure estimates (not accounting for duration of exposure and reflected exposure), calculated assuming distances of 30 cm, as the most conservative scenario. WRc plc