Radians Innova EnviroMentor Field Finder User manual

Field Finder
user instructions
English
Postal address: EnviroMentorAB, Box 5124, SE-402 23 Göteborg, Sweden.
Address (visitors): Gamla Almedalsvägen 6, Göteborg. Tel: [phone]. Fax: [phone].
E-mail: [e-mail] Home page: http://www.enviromentor.se
EnviroMentor has both the measuring
instruments and the expertise
EnviroMentor AB is a young, skills-based company, yet is also one of the
oldest in its field. All of our measuring instruments have been developed
in extremely close cooperation with researchers at Chalmers Institute of
Technology in Göteborg. EnviroMentor AB is wholly owned by Radians
Innova AB, a company which in turn is owned by two of Sweden’s most
powerful financial institutions. This combination of excellent skills and
good financial resources provides us with the potential to carry on continual
product development, keeping pace with the latest discoveries made by
researchers. You can find out all about our current range of measuring
instruments for the electrical environment from EnviroMentor’s various
product sheets. Please do not hesitate to contact us if you would like further
information.You can also visit our home page:
http://www.enviromentor.se
Karlssons Språkservice AB, Gothenburg, Sweden [phone]

Field FinderField Finder
2© Enviromentor AB 1998 reg. 98.011/Eng
© Copyright Enviromentor AB 1998
The contents of this manual may not be copied or duplicated
without the permission of Enviromentor AB.
Contents
1 Introduction ............................... 3
2 Technical data............................. 5
CE assurance..............................................5
Traceability.................................................6
3 Use............................................. 7
3.1 Measuring magnetic fields ..........................7
3.2 Measuring electric fields .............................7
3.3 Audible signal .............................................7
3.4 Threshold level ...........................................8
3.5 Changing the batteries.................................8
4 Measurement examples .............. 9
4.1 Electric fields ..............................................9
4.2 Magnetic fields..........................................10
4.3 Example of report form for measuring
magnetic fields..........................................12
5 How magnetic fields arise ......... 14
6 How electric fields arise............ 15
7 References to authorities and
organisations............................ 16
8 Report forms............................. 17
Report form A for measuring electric fields in
a room......................................................18
Report form for measuring electric fields
around an object .......................................20
Report form for measuring magnetic fields
around an object .......................................21
Notes............................................... 22
Notes

Field FinderField Finder
© Enviromentor AB 1998 reg. 98.011/Eng 3
1 Introduction
Thank you for buying a Field Finder from
EnviroMentor AB.
The equipment comprises:
• Field Finder electric/magnetic field meter
• User instructions
• Case
• Calibration document
• Earth cable
• Earth cable contact
• CE certificate
Field Finder measures electric or magnetic al-
ternating fields and presents the reading on an
LCD. The reading is updated every second. The
instrument emits an audible signal that is pro-
portional to the field strength measured.
Field Finder measures the electric field in the
direction of the measurement surface on the
instrument’s front short side.
Field Finder measures an RMS value of the
magnetic field in the X, Y and Z directions, ir-
respective of the direction in which the instrument
is pointing in relation to the magnetic field.
You can use Field Finder whenever you want to
measure electric fields, such as from electrical
installations, power cables, VDUs, computers
and other electrical equipment in the office, in-
dustrial and home environments.
Field Finder.
Cont.
Notes

Field FinderField Finder
4© Enviromentor AB 1998 reg. 98.011/Eng
The electric fields from a piece of apparatus are
influenced by the design of the instrument. Field
Finder is intended to give simple, general measu-
rements. If you want to carry out a more precise
analysis of the electrical environment, you should
use an instrument that has been designed in accor-
dance with MPR II. Field Finder does not satisfy
the requirements of MPR II, but the instrument
has been calibrated to produce the same results
when measuring electric fields at a distance of
50 cm from a VDU. Some measurement objects
may emit alternating fields with frequencies
beyond that which Field Finder can manage.
Notes
Report form for measuring magnetic fields around an object
Magnetic field, 30 Hz–2 kHz Measuring equipment: Field Finder
Object: Model:
Address: Room:
Measured by: Date:
30 cm 50 cm Comments
0°µTµT
90°µTµT
180°µTµT
270°µTµT
Background field µTµT
Report 98:3, Field Finder © EnviroMentor AB, Gothenburg, Sweden

Field FinderField Finder
© Enviromentor AB 1998 reg. 98.011/Eng 5
2 Technical data
Measurement range E 0–1,000 V/m
Accuracy E ±10% ±1 V/m at
50 cm
Measurement range B 0.05 µT–100 µT
Accuracy B ±10% ±0.05 µT
Frequency range 30 Hz–2 kHz (-3 dB)
Measurement method RMS effective value
Dimensions, L x W x H 152 x 83 x 34 mm
Weight 260 g (incl. batteries)
Batteries 2 x 1.5 V LR6
Power consumption 25 mA during mea-
surement
Temperature range -10°C to +50°C
Other Microprocessor, 10
bit A/D converter,
three-dimensional
sensor
CE assurance
Our product satisfies the demands of the Low
Voltage and EMC directive as well as the follo-
wing EMC standards:
EN 50 081-1:1992 Emissions standard
class B
EN 50 082-1 Immunity standard
Manufacturer EnviroMentor AB
Box 5124
SE-40223Gothenburg
Sweden
Report form for measuring electric fields around an object
Electric field, 30 Hz–2 kHz Measuring equipment: Field Finder
Object: Model:
Address: Room:
Measured by: Date:
30 cm 50 cm Comments
0°V/m V/m
90°V/m V/m
180°V/m V/m
270°V/m V/m
Background field V/m V/m
Notes
Report 98:2, Field Finder © EnviroMentor AB, Gothenburg, Sweden

Field FinderField Finder
6© Enviromentor AB 1998 reg. 98.011/Eng
EnviroMentor AB’s ca-
libration system
The Swedish National
Testing and Research
Institute
The Swedish Board
for Accreditation and
Conformity Assess-
ment, SWEDAC
FFV Measurement techn.
Laboratories accredited by SWEDAC in accordance with
Swedish legislation.
The accredited Swedish laboratories satisfy the demands
of SS-45001 (1989) and ISO/IEC standard 25 (1990:E).
Traceability chart.
Traceability
Traceability means that it should be possible to
relate a measurement result to national or inter-
national standards via an unbroken chain of
comparisons.
Report form B for measuring electric fields in a room
Electric field, 30 Hz–2 kHz Measuring equipment: Field Finder
Object: Model:
Address: Room:
Measured by: Date:
Measurement Measurement Background Comments
points reading* V/m field** V/m
1
2
3
4
5
6
7
8
9
10
11
12
* In the direction of the arrow on the sketch. ‘C’stands for ‘ceiling’, ‘F’stands for ‘floor’.
**The background field does not need to be measured at all measurement points.
Notes
Report 98:1B, Field Finder © EnviroMentor AB, Gothenburg, Sweden

Field FinderField Finder
© Enviromentor AB 1998 reg. 98.011/Eng 7
3 Use
3.1 Measuring magnetic fields
Start up the instrument with the switch. The in-
strument always starts in magnetic field mode
and displays the magnetic field’s effective va-
lue in µT. This value is updated at 1 second in-
tervals. Field Finder can be pointed in any di-
rection in relation to the magnetic field source
as it has a three-dimensional sensor.
3.2 Measuring electric fields
Start up the instrument with the switch. Change
the measurement function by pressing the E-key
once. Hold the instrument in the required direc-
tion. The instrument now measures the electric
field in the direction in which it is currently
pointing, and displays the effective value in V/m.
The reading is updated at 1 second intervals.
Note that the field can be influenced by objects
in the vicinity of the instrument, as well as by the
person holding it. The instrument has to be held
still in order to achieve a stable value. When me-
asuring electric fields from pieces of apparatus,
the instrument should be earthed. Connect the
accompanying earth cable to the output.
The instrument can also be used without con-
necting the earth cable. In this event, hold your
finger against the earth output on the left side
of the instrument. The fields you then measure
are those which the user of the piece of equip-
ment is exposed to when working. These fields
are dependent on the user’s and the sources’
connection to each other and to earth.
3.3 Audible signal
The audible signal can be turned on or off by
pressing down both the function keys at the
same time.
Measuring magnetic fields.
Measuring electric fields.
Report 98:1A, Field Finder © EnviroMentor AB, Gothenburg, Sweden
Sketch of the room with measurement points marked.
Report form A for measuring electric fields in a room

Field FinderField Finder
8© Enviromentor AB 1998 reg. 98.011/Eng
Battery symbol.
E (V/m) B (µT)
10 0.2
20 0.4
50 1.0
99 2.0
Threshold levels.
3.4 Threshold level
The threshold level indicates the field strength
at which the instrument’s audible signal is first
emitted. The threshold level can be selected by
the user in accordance with the table. The stan-
dard settings when the instrument is switched
on are 10 V/m and 0.2 µT. If you want to select
a different value, hold one of the keys depres-
sed while starting up the instrument. Then se-
lect the desired limit using the appropriate key.
To exit the setting procedure, press both keys at
the same time. The selected threshold level is
stored as long as the instrument is switched on.
3.5 Changing the batteries
When the battery symbol is displayed to the left
of the measurement reading, the batteries should
be replaced immediately. Unscrew the cover on
the rear of the instrument, remove the old batte-
ries and install new ones (2 x 1.5 V LR6).
8 Report forms
On the following pages you will find report form
templates for measuring electric and magnetic
fields. Copy the templates, fill them out and then
file them in a folder. You can then go back and
make comparisons with previous measurements.
Section 4 gives examples of how to carry out
measurements, while subsection 4.3 details how
to fill out the report forms.
Report form for measuring electric
fields.
Report form for measuring
magnetic fields.
Report form for measuring electric fields around an object
Electric field, 30 Hz–2 kHz Measuring equipment: Field Finder
Object: Model:
Address: Room:
Measured by: Date:
30 cm 50 cm Comments
0°V/m V/m
90°V/m V/m
180°V/m V/m
270°V/m V/m
Background field V/m V/m
Notes
Report 98:2, Field Finder © EnviroMentor AB, Gothenburg, Sweden
Notes
Report form for measuring magnetic fields around an object
Magnetic field, 30 Hz–2 kHz Measuring equipment: Field Finder
Object: Model:
Address: Room:
Measured by: Date:
30 cm 50 cm Comments
0°µTµT
90°µTµT
180°µTµT
270°µTµT
Background field µTµT
Report 98:3, Field Finder © EnviroMentor AB, Gothenburg, Sweden

Field FinderField Finder
© Enviromentor AB 1998 reg. 98.011/Eng 9
4 Measurement examples
4.1 Electric fields
Below is a suggestion as to how to measure an
electric field in a room within the frequency
range 30 Hz to 2,000 Hz.
1. Start by carrying out a preliminary measure-
ment with all the pieces of electrical equipment
switched on and make a rough estimate of what
field sources are present in the room. Draw a
sketch of the room. Then measure a number of
points at 1-3 metre intervals by taking readings
in all directions in a circle around you. Write
down the highest value measured at each point
on the sketch. Using an arrow, mark the direc-
tion in which you obtained the value you have
written down. Ideally, note the field levels
towards the ceiling and the floor.
2. Then carry out a measurement with all the
electrical apparatus in the room switched off
to get an idea of the extent of the background
fields in the room. Remember that it is probably
not sufficient simply to switch off the pieces
of apparatus - you will usually need to unplug
them in order to completely eliminate the fields.
In some cases, the background fields can be as
high as the fields from the apparatus in the room.
3. Connect the pieces of apparatus one at a time
and measure the electric fields in the directions
0°, 90°, 180°and 270°at distances of 30 cm
and 50 cm from the outer edge of the piece of
apparatus in question (see figure) or in the
direction the operator is facing. Summarise the
measurement readings in a report form. An
example of how to fill out a report form can be
found on page 12. You must not subtract the
background values of the electric fields from
the measured values. They should always be
noted as a comparison.
50 cm
50 cm
Overhead view.
Side view.
Cont.
7 References to authorities and organisations
Publication Publisher/Author May be ordered from
Magnetic fields and health
risks based on what we
know
The National Electrical
Safety Board Elsäkerhetsverket
Box 1371
SE-111 93 STOCKHOLM
SWEDEN
Tel. [phone]
Fax. [phone]
Cancer and magnetic fields
in workplace The Swedish Trade Union Confederation LO-distribution
Strömsätragränd 10
SE- 127 35 SKÄRHOLMEN
SWEDEN
Tel. [phone]
Questions and answers about
electric and magnetic fields
associated with the use of
electric power
National Institute of Environ-
mental Health Sciences and
U.S. Dep. of Energy
Superintendent of Documents
U.S. Goverment
Printing Office
WASHINGTON, D.C. 20 402
USA
Tel. [phone]
A report of non-ionizing
radiation Microwave News Microwave News
Louise Slesin
P.O. Box 1799
Grand Central Station
NEW YORK, N.Y. 10 163
USA
[phone]
[phone]
[email protected]

Field FinderField Finder
10 © Enviromentor AB 1998 reg. 98.011/Eng
4. Analyse the measurement readings and assess
the need for remedial action, such as rearranging
the furniture in the room and/or moving pieces
of electrical apparatus. The sources of the elec-
tric fields may be located in adjacent rooms.
Certain materials, not only metals, can also
function as antennas as they capture fields
and increase their spread. Plasterboard and
chipboard can have this effect.
4.2 Magnetic fields
Below is a suggestion as to how to measure a
magnetic field in a room within the frequency
range 30 Hz to 2,000 Hz.
1. Start by carrying out a preliminary measurement
with all the pieces of electrical equipment swit-
ched on and make a rough estimate of what field
sources are present in the room. Draw a sketch
of the room. Then measure a number of points
at 1–3 metre intervals and write down the values
measured on the sketch. Measure the magnetic
field at floor level as well as 0.8 and 2 metres
above the floor.
2. Then carry out a measurement with all the
electrical apparatus in the room switched off
to get an idea of the extent of the background
fields in the room. Remember that it is probably
not sufficient simply to switch off the pieces
of apparatus - you will usually need to unplug
them in order to completely eliminate the fields.
In some cases, the background magnetic fields
can be more powerful than the magnetic fields
from the apparatus in the room.
50 cm
50 cm
Overhead view.
Side view.
Cont.
Electric field.
Electric fields from our surroundings.
6 How electric fields arise
An electric field arises between two objects with diffe-
rent electric potentials. If two plates made of electri-
cally conductive material are connected to a voltage
source, one of the plates will have a positive charge
while the other will have a negative charge.Avol-
tage arises between the plates and thereby an elec-
tric field. The strength of the field depends on how
high the voltage is and the distance between the objects.
In a similar way, we are continually exposed to
electric fields from pieces of apparatus and elec-
trical installations in our surroundings. The size
of the fields around us are difficult to predict as
they depend on the connection between the sources
of the fields, the people and earthing. There are
often a number of different sources of varying
strengths in a single room.
Objects that are not connected to electricity can
also be affected by electric fields. A metal object
can be capacitively charged by nearby cabling or
other objects connected to electricity. In simple
terms, the metal object functions as an antenna,
capturing the electric field and helping it to grow.
Examples of such objects include desk frames
and electrical devices with non-earthed metal
casings. Some types of building material (plaster-
board walls, chipboard) can also capture electric
fields and increase their spread. When measuring
fields in a room which has plasterboard walls, it
can sometimes be seen that the fields spread out
along an entire wall surface with the highest readings
being concentrated around sockets and switches.
Electric fields can be reduced through screening
and earthing. It is possible to use shielded cabling
or to place screening material around the object
that is to be screened off. In order for the screening
to be effective, it is important for the screening
material to be properly earthed. If this is not the
case, screening can have the opposite effect –
the fields increase in size.

Field FinderField Finder
© Enviromentor AB 1998 reg. 98.011/Eng 11
3. Connect the pieces of apparatus one at a time
and measure the magnetic fields in the direc-
tions 0°, 90°, 180°and 270°at distances of
30 cm and 50 cm from the outer edge of the
piece of apparatus in question (see figure) or
in the direction the operator is facing. Sum-
marise the measurement readings in a report
form. An example of how to fill out a report
form can be found on page 12. You must not
subtract the background values of the magnetic
fields from the measured values. They should
always be noted as a comparison.
4. Analyse the measurement readings and assess
the need for remedial action, such as rearranging
the furniture in the room and/or moving pieces
of electrical apparatus. The sources of the
magnetic fields may be located some distance
away, and magnetic fields can penetrate almost
all building materials.
5 How magnetic fields arise
Magnetic fields are caused by electrical cur-
rents and always occur in continuous closed
paths around the currents that cause them. A
live conductor gives rise to a magnetic field,
the strength of which is always proportional to
the current in the conductor. Magnetic fields
are usually depicted with the aid of field lines.
The strength of the magnetic field is constant
along the conductor in closed paths around the
live conductor. In the event of other sources,
magnetic fields tend to have a complicated ap-
pearance which usually cannot be calculated
but have to be measured instead. The unit used
to measure the magnetic flux density is called
the tesla [T]. Magnetic fields can be caused by
electrical devices and installation cables. In cer-
tain cases, stray currents can give rise to mag-
netic fields. In Sweden, for example, the elec-
tricity systems generally entail four conductors
leading to each building, which can result in
major problems with currents of this type. The
decay current can pass through the neutral con-
ductor as intended, but it can also pass through
the earth conductor and into the plumbing pipe-
work to the transformer’s earth point. This in-
creases the magnetic field both along the path
of the stray current and along the supply cable.
It is also commonplace for stray currents to ex-
ist in computer networks. As well as causing
magnetic fields, they can also lead to communi-
cation problems. In industrial environments,
common sources include welding equipment,
electric motors and cable clusters.
Straight con-
ductor, I=1A
At 1 m from the conductor, the
magnetic flux density is 0.2 µ T.

Field FinderField Finder
12 © Enviromentor AB 1998 reg. 98.011/Eng
4.3 Example of report form for mea-
suring magnetic fields
When you measure magnetic fields, you should
produce a report form which can act as a basis
for any remedial action. Below is an example of
a completed report form. Report form templates
which you can copy can be found at the back of
these user instructions. Once you have filled out
the forms, they should be filed in a folder. You
can then go back and make comparisons with
previous measurements.
Photocopier FT 30
1 North Street Porter’s office
J. Smith 10 March 1995
20 10 During copying
30 10
40 20
30 10
33
The background fields are OK, but perhaps we
should screen off the copier or rearrange the fur-
niture.
Example of a completed report form for measuring
electric fields around an object.
Report form for measuring electric fields around an object
Electric field, 30 Hz–2 kHz Measuring equipment: Field Finder
Object: Model:
Address: Room:
Measured by: Date:
30 cm 50 cm Comments
0°V/m V/m
90°V/m V/m
180°V/m V/m
270°V/m V/m
Background field V/m V/m
Notes
Report 98:2, Field Finder © EnviroMentor AB, Gothenburg, Sweden
© Enviromentor AB 1998 reg. 98.011/Eng 13
Example of a completed report form for measuring electric fields in a room.
wardrobe
desk 1 ➚
2 ➙
3 ➘
4 ➘
14
18
21
7
5 Fluorescent-
tube in the
ceiling
5 C
3 High Street 123
P. Jones 13 May 1998
Report 98:1A, Field Finder © EnviroMentor AB, Gothenburg, Sweden
Sketch of the room with measurement points marked.
Report form A for measuring electric fields in a room
Report form B for measuring electric fields in a room
Electric field, 30 Hz–2 kHz Measuring equipment: Field Finder
Object: Model:
Address: Room:
Measured by: Date:
Measurement Measurement Background Comments
points reading* V/m field** V/m
1
2
3
4
5
6
7
8
9
10
11
12
* In the direction of the arrow on the sketch. ‘C’stands for ‘ceiling’, ‘F’ stands for ‘floor’.
**The background field does not need to be measured at all measurement points.
Notes
Report 98:1B, Field Finder © EnviroMentor AB, Gothenburg, Sweden