R&D programme
Research brief
Investigation into the effects of
applying the Physical Agents (EMF)
Directive on the UK railway system
Background
The Electromagnetic Fields (EMF) Directive 2013/35/EU, was published by
the European Commission on 29 June 2013. It is to be implemented in UK
law by 1 July 2016 and supersedes the 2004 Directive: Physical Agents
(Electromagnetic Fields).
This Directive deals with health and safety in the work place relating to
electromagnetic fields. It will apply to work activities where employees
may be exposed to acute risks from electromagnetic fields, with the aim of
establishing common minimum EMF safety standards, across all member
states of the European Union. The Directive includes requirements for
proportionate work place risk assessments, control of exposure (with
exposure limits and stated action values), appropriate health surveillance,
information, working instructions and training for affected workers.
European member states are required to transpose the Directive into their
respective national legislation by 1 July 2016.
Aims
The purpose of this study was to review the work previously undertaken
(Project T515 Investigation into the effect of the Physical Agents
(Electromagnetic Fields) Directive on railway operations) to assess the
effects of the 2004 directive on the UK rail industry, and to consider how
the 2013 Directive will impact upon the rail industry.
This research was undertaken to:
1 Determine the areas in which the GB rail industry is within the EMF
limits.
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2 Identify where further work needs to be undertaken. This includes
investigation into requirements in the new Directive not covered by
T515, as well as more detailed guidance on EMF measurements at
specific sites, and how to prepare risk assessments.
Findings
The work carried out in T515 (modelling and testing) has been reviewed
with respect to the new EMF Directive and the conclusion is that it remains
valid. The particular cases of concern identified have the same or more
relaxed limits in the 2013 EMF Directive. The greatest change in the 2013
EMF Directive is in the process for achieving compliance.
Further work has been identified, such as the need for a railway-specific risk
assessment process, and the modelling and assessment of standard cases
like stations and technical equipment rooms.
Compliance with 2013/35/EU
The 2013 Directive is similar to the 2004 Directive in terms of the exposure
limits with a relaxation in some areas, but has more stringent values in the
electric field limits in the frequency range 1kHz to 1MHz. The static field
limits for pacemakers are given more weight in the 2013 Directive.
The Directive requires that the assessment must be risk-based, and
depends upon exposure level, exposure pattern and frequency (of
exposure).
The Directive distinguishes between near-field and far-field effects giving
separate definitions for the electric, magnetic, and electromagnetic
(radiated) fields. No definitive frequency threshold is given for the
transition between separate electric and magnetic, and electromagnetic
values. Limits are given for electric and magnetic fields covering the whole
spectrum up to 300GHz, although at frequencies above 6GHz power-based
specific absorption rate level limits are also given.
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R&D programme: Research brief T1051 - May 2015
T515 project review
The objective was to establish if the typical current railway environments
would meet the levels defined in the 2004 Directive.
Modelling looked at a variety of sources and systems (such as AWS/APC
magnets, TPWS loops, tuned zones of track circuits, rolling stock traction
and motor cables, traction motors, inductors and chokes used in rail vehicle
electric traction equipment, train cabs, and traction system faults). It was
concluded that all these systems were likely to be compatible with the
2004 Directive limits.
To validate the modelling work typical railway environments were
measured, including:
• Depots (AC)
• Rolling stock (AC/DC)
• Stations (AC Mainline)
• DC substations (measured by Network Rail)
The significant exposure cases identified were:
• The 50Hz electric field level directly under the catenary (such as on a
walkway in a depot)
• 50Hz magnetic field close to overhead or feeder cables (such as the
transformer feeder cable on AC rolling stock)
• Magnetic fields at DC substations
Other industries' concerns
Other industries which have funded research in this area and expressed
concerns about achieving compliance include:
• Mobile telecommunications
• Radio systems
• Magnetic resonance imaging
• Welding
• Electrolysis and electroplating
Of particular relevance to the rail industry are the concerns expressed by
The Welding Institute. Although, for most welding associated with the
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railway (rail to rail) the machinery involved would keep the operator at a
safe distance.
In future, where products fall within the scope of Low Voltage Directive,
Machinery Directive, or Radio Equipment Directive, they will be assessed
for compliance with occupational EMF requirements.
In terms of participating and commenting on the occupational exposure
limits, significant work has been limited to a few medical and industrial
sectors:
• Magnetic resonance imaging
• Electric arc and resistance welding
• Electrolysis and electro-plating
Gap analysis
It is possible that some areas of electric field exposure on the railway will
lie between the Low Action Level and High Action Level, such as the
circumstances described in the T515 project. In this case the
documentation needed will include:
• Risk assessment
• External documentation
• Measurement results (if applicable)
• Assessment (if applicable)
• Preventative measures to be applied
• Protective measures to be applied
• Mitigation action plan
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R&D programme: Research brief T1051 - May 2015
Lack of railway 'standard cases'
Public Health England has prepared guidance on behalf of the Commission
on the application of the new Directive. The main focus of the guide is:
• The determination of exposure, taking into account appropriate European
or international standards
• Guidance on demonstrating compliance in special types of non-uniform
exposure in specific situations, based on well-established dosimetry
• The description of the 'weighted peak method' for low frequency fields, and
of the 'multi-frequency fields summation' for high frequency fields
• The conduct of the risk assessment and, wherever possible, the provision of
simplified techniques, taking into account in particular the needs of subject
matter experts
• Measures aimed at avoiding or reducing risks, including specific prevention
measures depending on the level of exposure and the workplace
characteristics
• The establishment of documented working procedures, as well as specific
information and training measures for workers exposed to electromagnetic
fields during MRI related activities
• The evaluation of exposures in the frequency range from 100 kHz to 10
MHz, where both thermal and non-thermal effects are to be considered
• The guidance on medical examinations and health surveillance to be
provided by the employer
We anticipate that the railway environment will not be included in the
'standard cases' described. Although some aspects of the railway will
resemble expected standard cases such as shopping centres.
AC network supply voltage ripple
Exposure outside the train may not have been effectively assessed as part
of T515. The exposure scenario of concern would be time limited, requiring
a train in the vicinity, and the exposed person to be in the highest location
on the track, which is an infrequent location for staff (in T515
measurements were made in a depot at crossing points).
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DC substation harmonics
A DC substation produces harmonic voltages related to the supply
frequency, number of rectifier pulses, and dependent on the load current.
However it is concluded that the likelihood of exceeding the electric field
limits on DC traction supplies is negligible.
Method
The project encompassed desk top studies of the work done on the 2004
Directive under T515 and of work done by other industries and third parties
on the new Directive. It established whether the T515 work on the 2004
Directive had any gaps that needed additional studies; and reviewed it to
establish compliance with the new methodology given in the EMF Directive
2013/35/EU.
Areas of concern
The assessment methodology in 2013/35/EU requires an assessment
(measurement or calculation) against the action levels unless:
• The equipment complies with the action levels (such as equipment certified
to the Low Voltage Directive, or certified by the manufacturer)
• The situation complies with a standard case (likely to be defined in the
guidance document, for example typical office and shop environments)
• An assessment has been carried out or the environment has been
determined to comply with a more rigorous requirement (Public
Recommendation 1999/519/EC)
Cooperation with HSE in the drafting of the UK legislation and guidance
can assist the railway industry by ensuring employers and employees can
readily identify those low risk situations which do not require assessment,
as well as any medium or high risk situations needing more detailed
assessment or mitigation. Typical areas that may need further assessment
are detailed in Table 1.
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R&D programme: Research brief T1051 - May 2015
Table 1 - Typical railway situations requiring further assessment
Location
Task
On a GSM-R or radio base station
antenna mast/tower
Climbing mast directly in front of
energised antenna.
Within DC substation
Entering operational DC substation with
high current or voltage conductors.
Within AC feeder station
Entering operational AC substation with
high current or voltage conductors.
Adjacent to electric arc or flash
butt welding
Remaining close to high current carrying
cables during electric arc or flash butt
welding processes.
Further work
The project findings recommend that the further research work identified
in this study should be carried out to allow the railway industry to be
prepared to implement the EMF Directive in a timely, efficient and
effective manner when it comes into force in 2016. The further research
work will provide:
1 A railway-specific risk assessment process, based on BS EN 50499 with
guidelines and supporting information for typical railway
environments.
2 The modelling and assessment of standard cases (based on
Commission Guidance and the BS EN 50499 approach) for each of:
a
Stations (non-electrified, AC, DC and dual voltage areas)
b
Lineside environment (non-electrified, AC, DC and dual voltage
areas)
c
Depots (non-electrified, AC, DC and dual voltage areas)
d
Technical equipment rooms (signalling and telecommunications)
e
Feeder or substations (AC/DC) and switching locations
f
Low voltage equipment rooms and trackside cubicles
g
Rolling stock (passenger, freight, diesel, AC, DC, dual)
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3 Research into, and mitigations for the effects of, electric fields due to
supply ripple in the 25 kV AC supply.
4 Research into, and mitigations for the effects of, electromagnetic fields
generated in the railway on staff fitted with pacemakers whilst working
in the railway environment; and on the particular hazards of AWS
magnets, conductor rails, and DC feeder cables.
5 Research into, and mitigations for the effects of, contact current in
particular on example maintenance vehicles and road/rail vehicle in
transition mode on the 25 kV AC network.
6 Recommendations for the content of a fact sheet on electromagnetic
fields and human health as applicable to the UK railway.
Deliverables
This research has produced a report that summarises our findings:
Investigation into the effects of applying the Physical Agents (EMF)
Directive in the GB railway system.
This is available through SPARK (sparkrail.org).
Next Steps
The Future Electrification Group (FEG) has accepted that the objectives of
this research have been addressed and has agreed the findings.
The members of the FEG have proposed that further work is undertaken to
deliver the informed technical content for the guidance and standard
cases for the industry to achieve compliance with the EMF Directive.
The timescales of this further work would need to be such that the
technical content is available to industry in advance of the implementation
of the Directive into UK law in mid-2016.
Contact
For more information please contact:
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R&D programme: Research brief T1051 - May 2015
Professional Lead - Engineering R&D
R&D Programme
RSSB
enquirydesk@rssb.co.uk
Floor 4, The Helicon
1 South Place
London EC2
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