What is it?
Static magnetic fields remain constant over time and, unlike alternating current, are not associated with an operating frequency.
The main static magnetic field in our surroundings is the Earth’s magnetic field, which is the natural reference for any assessment. Certain materials and building elements can alter it locally and cause deviations.
The SBM-2024 includes magnetostatics among the physical factors of the indoor environment. The interest lies not only in the strength of the field, but in deviations from the Earth’s natural field and in locating the sources that cause them.
Where can it be found?
Disturbances can be caused by metal beams and columns, concrete reinforcement, metal furniture, steel pipework, tanks, load-bearing structures, machinery, permanent magnets and other ferromagnetic elements.
Their distribution depends on the construction of the building and on proximity to those elements. In some cases the deviations are very localised and in others they affect wider areas, which means that the areas where people spend long periods must be assessed systematically.
How is it assessed?
What the inspection looks at
The technical inspection identifies possible ferromagnetic elements and the way the building is constructed.
What is recorded for each measurement
Equipment, quantity, unit, location, date, measurement conditions and duration, together with the relevant limitations and the interpretation criterion applied.
How this factor is measured
Measurements are taken with specialist professional instruments for static magnetic fields, recording both the field strength and the deviations from the natural field.
Depending on the results, a map of the deviations detected may be produced, to locate the affected areas precisely and support the technical interpretation.
In assessments intended as expert evidence, calibrated instruments are used to ensure the reliability and traceability of the measurements.
Criteria
Interpretation follows the SBM-2024, taking into account the guidance values for static magnetic fields and the deviations from the Earth’s magnetic field.
The final assessment considers the spatial distribution of the disturbances, the intended use of the rooms and the interaction with the other physical, chemical and biological factors assessed.
This guide does not publish values or thresholds. Technical criteria, legal limits and recommendations are different things and are not presented as equivalent.
Improvement measures
Work always begins by understanding and, where possible, reducing the source, before acting on the path or on the space. Measures are prioritised by expected effect, feasibility and proportionality, and no products are recommended by default.
The action taken depends on the origin of the deviations detected. Options that may be considered include:
- Relocating certain metal elements where feasible.
- Rearranging furniture.
- Removing avoidable sources.
- Adapting the layout of the spaces.
Each recommendation is made after an individual assessment and takes into account the construction of the building.
How Cemprotecta helps
This factor is not assessed on its own. It is measured as part of an assessment that treats the space as a system, because the deviations depend on the structure of the building and on where the areas in which people spend time are located.
What an assessment gives you is knowing what is there, where it is and what can be done about it, with an ordered sequence of measures rather than a list of problems.
- Inspection of the space and of accessible installations.
- Measurement in the rooms where people spend most time.
- Combined interpretation with the other factors assessed.
- A report with measures ranked by their expected effect on exposure.
Request an assessment
If this factor concerns you in your home or workplace, tell us about your case. The prior inspection will determine whether it is worth measuring and what else should be assessed alongside it.