Shielding low-frequency magnetic fields

MuFerro low-frequency magnetic shielding

Magnetic field reduction for technical, medical and industrial environments

MuFerro shielding is designed to reduce low-frequency magnetic fields around transformer rooms, busbars, high-current installations, laboratories, medical equipment and other sensitive environments.

Holland Shielding Systems B.V. supports the complete process: magnetic field measurement, shielding advice, engineering, in-house production, installation and verification after installation.

  • Suitable for DC to 100 kHz applications
  • Optimized for 50/60 Hz magnetic fields
  • Available as material, construction or complete project

Discuss your project

MuFerro low-frequency magnetic shielding installed above a transformer room

Custom MuFerro magnetic shielding installed above a transformer room.

Where MuFerro shielding is used

Low-frequency magnetic fields can occur around transformers, cables, busbars and other high-current systems. MuFerro shielding helps reduce these fields in areas where people, measuring equipment or sensitive systems are nearby.

MuFerro shielding for transformer rooms and substations
Transformer rooms

Magnetic shielding around transformers, substations and electrical rooms.

MuFerro shielding for busbars and high-current cables
High-current systems

Field reduction around busbars, high-current cables and power distribution systems.

MuFerro magnetic shielding for medical facilities and sensitive equipment
Medical facilities

Magnetic shielding for medical rooms and sensitive diagnostic equipment.

MuFerro magnetic shielding for laboratories and sensitive measurements
Scientific laboratories

Shielding for laboratories, measuring rooms and technical research environments.

Why use magnetic shielding?

Low-frequency magnetic fields can interfere with monitors, measuring equipment, medical systems and other sensitive electronics. They can also extend into offices, laboratories or public areas located near electrical installations.

The required field reduction depends on the application, customer specification, measurement method, source, frequency and distance. Each project is assessed separately.

What Holland Shielding Systems provides
  • Magnetic field measurement before shielding
  • Identification of the probable field source
  • Advice on shielding concept and layer build-up
  • Engineering based on the room and installation
  • In-house production of MuFerro components
  • Installation support and verification measurement
Customer story: office above a transformer room

A customer wanted to convert a storage room into an office. The room was located directly above several power transformers. Magnetic field interference caused computer displays in the room to flicker.

Problem

An on-site survey measured a magnetic field strength of approximately 750 nT inside the intended office.

Solution

Our engineers designed a custom MuFerro umbrella construction above the transformers. The existing electrical installation did not need to be relocated.

Measured result

After installation, the measured magnetic field strength was reduced from approximately 750 nT to approximately 80 nT.

Magnetic field before installing MuFerro shielding
Before shielding

Measured magnetic field strength of approximately 750 nT.

Magnetic field after installing MuFerro shielding
After shielding

Measured magnetic field strength reduced to approximately 80 nT.

MuFerro magnetic shielding material

MuFerro is suitable for magnetic shielding in the frequency range from DC to 100 kHz and is optimized for 50/60 Hz applications.

  • Standard sheet size: 2000 x 1000 mm
  • Can be applied in multiple layers
  • Suitable for walls, floors, ceilings and local enclosures
  • Suitable for new and existing installations
  • Can be incorporated into project-specific constructions
Project-specific MuFerro magnetic shielding construction around transformers

Project-specific shielding construction for a demanding transformer application.

MuFerro shielding types

The final material selection depends on the field source, frequency, magnetic flux density, required reduction and construction.

Property Unit MF-FS MF-ECFC
Density g/cm3 8 4
Thickness mm 0.7 4.7
Resistivity Ohm·m 5E-7 3E-7
Curie temperature °C 400 400
Maximum μr at DC - 3800 3800
Maximum μr at 50 Hz - 3750 3750
Maximum μr at 60 Hz - 3700 3700
Minimum yield strength N/mm2 300 105
Minimum tensile strength N/mm2 400 85
Hardness N/mm2 150 30
MuFerro MF-FS

MF-FS combines magnetic permeability with suitable saturation characteristics. It is designed for reducing low-frequency magnetic fields and can be applied in multiple layers.

MuFerro MF-ECFC

MF-ECFC combines magnetic properties with additional eddy-current performance. It can be spot-welded on location to create a more continuous shielding surface.

Project-specific design

The shielding concept depends on the source, field strength, distance, room layout, required reduction and available installation space.

MuFerro DC performance

The graph shows the relative permeability of MuFerro under DC magnetic field conditions.

MuFerro DC relative permeability performance graph

Please note: These values are measured under laboratory conditions. Results may vary in other situations; please read our Guarantee

MuFerro AC performance at 50/60 Hz

The graph compares the relative permeability of MuFerro at 50 Hz and 60 Hz.

MuFerro AC relative permeability performance graph at 50 and 60 Hz

Please note: These values are measured under laboratory conditions. Results may vary in other situations; please read our Guarantee

Shielding characteristics

Magnetic shielding performance can be expressed as a shielding factor. The final reduction depends on the magnetic field strength, frequency, material type, number of layers, construction geometry and installation quality.

MuFerro-FS can be installed in multiple layers. MuFerro-ECFC can be spot-welded to create a more continuous shielding surface.

Magnetic shielding reduces magnetic field strength. It does not completely block the magnetic field.

MuFerro shielding factor for low-frequency magnetic field reduction
Retrofit installation

MuFerro shielding can often be installed after transformers, busbars or other electrical equipment have already been placed.

Depending on the magnetic field distribution, the shielding can be installed on a wall, ceiling, floor or directly around the source.

Finishing after installation

The shielding can remain visible in a technical room or be covered as part of the final wall, floor or ceiling construction.

The final finish depends on the project requirements and the intended use of the room.

MuFerro magnetic shielding installed above a transformer room

MuFerro magnetic shielding installed above a transformer room.

Heavy MuFerro shielding construction around transformer equipment

Heavy MuFerro shielding construction for transformer equipment.

Magnetic field verification

The magnetic field is measured before the shielding concept is finalized. After installation, a follow-up measurement can verify the achieved field reduction.

The measurement method, positions and operating conditions should be recorded so the before-and-after results can be compared correctly.

A measurement report can be supplied when required for the project.

Measurement to verify MuFerro magnetic shielding performance
Typical MuFerro project process
1. Measure

We identify the magnetic field source, field strength, frequency and affected area.

2. Engineer

Our engineers define the shielding surface, material type and required layer build-up.

3. Produce and install

Shielding components are produced in-house and prepared for installation.

4. Verify

The final magnetic field reduction can be checked with a follow-up measurement.

Information required for a quotation

Please provide as much of the following information as possible. When some details are unavailable, our specialists can help determine what is required.

Drawings and dimensions
  • Cross-sectional sketch or technical drawing
  • Dimensions of the magnetic field source
  • Dimensions of the protected area
  • Available installation space
Position and distance
  • Horizontal distance from the source
  • Vertical distance from the source
  • Position above, below or next to the source
  • Location of sensitive equipment or occupied areas
Technical data
  • Current in amperes
  • Transformer capacity in kVA
  • Transformer, cable or busbar type
  • Operating frequency
  • Available magnetic field measurements
Need low-frequency magnetic shielding?

Send us your drawing, technical data, measurement results or project description. Our engineers can help determine whether MuFerro shielding is suitable for your application.

We can assist with magnetic field measurement, engineering, material selection, production, installation and verification.

Contact our engineers

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