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DIN EN ISO 11690
28.05.2026Before the first acoustic barrier goes up, you need to know exactly where your plant is really too loud and by how many decibels. A proper measurement provides that foundation and replaces guesswork with reliable figures. This guide shows you how to go about it and which standard sets the framework.
Workplace Noise Measurement from Sound Measurement to Noise Register
Workplace noise measurement is the first and most important step toward a plant where people and machines work together more quietly. Before a single measure is planned, it has to be clear where the exposure arises and how high it actually is. Reliable readings replace every assumption and form the basis for the risk assessment, the noise register and precisely fitted noise control.
As sta Group, we have guided industrial companies through exactly this process for more than 38 years, from the first analysis to the finished solution. This guide shows you how a sound measurement runs in practice, which standard sets the framework and how individual readings finally turn into a complete noise map of your hall.
Why Measuring Noise in Your Plant Is the First Step to Effective Noise Control
Measuring noise in your plant means gaining clarity about a problem you can hear but rarely judge precisely. Two identical halls can differ by several decibels, depending on machine layout, ceiling height and wall material. Only the measurement turns a vague impression of noise into a manageable quantity.
Without figures there is no priority. You do not know which machine is the real driver, which workstation is critical and which areas are unremarkable. A sound noise measurement delivers exactly this ranking and keeps your budget from landing in the wrong place.
Noise Risk Assessment as the Employer’s Duty
The noise risk assessment is a legal requirement and begins with determining the actual exposure. As soon as relevant levels can be expected at a workstation, the employer must assess the exposure. The applicable action values are laid down in Germany in the Noise and Vibration Occupational Health and Safety Ordinance (LärmVibrationsArbSchV).
At the same time, the measurement is not an end in itself but the reliable core of that assessment. Without determined values, neither a hazard nor its elimination can be demonstrated. The specific threshold values and their meaning belong to the dedicated topic of workplace noise levels.
What Measuring Prevents in Terms of Poor Planning and Unnecessary Costs
When planning follows gut feeling rather than measured values, expensive mistakes almost always follow. An oversized enclosure costs unnecessarily much, while an undersized measure misses its target. Both can be avoided with a clean baseline measurement.
A reliable measurement also shows whether to tackle the source or rather the room in the first place. That way every euro invested flows into the measure with the greatest effect. Measuring is therefore not the expensive route, but the economical one.
How Noise Measurement, Sound Measurement and the Noise Register Fit Together
What is the actual difference between the many terms used in plant acoustics? A sound measurement captures a momentary level at a single point. The noise measurement is something different, assessing a person’s exposure across the entire working shift. The noise register finally brings these values together into a spatial map of the plant.
Keep these three levels cleanly apart and you will understand your own results far better. A single high value at a machine still says little about the personal risk to an employee who only spends part of the time there.
Single Reading, Exposure Measurement and Mapping
First, the single reading provides the sound pressure level at a defined spot at one moment. It is suitable for identifying a loud source or comparing one machine with another.
The exposure measurement goes a step further and weights all levels over the duration of the activity. Only from this does personal exposure emerge. The noise register then condenses many measurement points into an overall picture of the hall and makes noise hotspots visible at a glance.
Measuring Noise Emission at the Source and Exposure at the Workplace
Measuring noise emission means capturing the sound at the source, that is directly at the machine or system. These values describe how much sound a device gives off, regardless of who is nearby.
At the workplace, by contrast, what counts is the immission, which depends on distance, room acoustics and time spent there. Emission and immission are two sides of the same coin and belong in every sound assessment. Only when both are considered can you decide whether to enclose the source or dampen the room.
Which Instruments and Standards Govern Workplace Noise Measurement
A clear technical framework applies to workplace noise measurement. The central standard is DIN EN ISO 9612, which describes the procedure for determining the noise exposure level as an engineering method of accuracy class 2. In addition, the German technical rules TRLV Lärm Part 2 govern the practical implementation on site.
Just as important as the method is the tool. An unsuitable or badly set device produces figures that hold up before no authority and no planning. A look at instrument classes and calibration is therefore worthwhile.
Sound Level Meters of Class 1 and Class 2
Sound level meters are divided into two accuracy classes that differ above all in the permissible tolerance. Choose the right class for your plant measurement deliberately.
| Feature | Class 1 | Class 2 |
|---|---|---|
| Measurement uncertainty | lower, tighter tolerance | higher, wider tolerance |
| Frequency behaviour | broader and more precise | more limited |
| Typical use | legally sound and reference measurements | orienting measurements in the plant |
When it comes to the documented risk assessment or to evidence for the authorities, a class 1 device is the safe choice. A class 2 device is enough for a first overview but reaches its limits at critical values.
Calibration and Accuracy of the Measuring Chain
A sound level meter is only as good as its calibration. Check the device with an acoustic calibrator before and after every measurement series so that deviations show up immediately. An unnoticed drift in the measuring chain makes even the most careful measurement worthless.
In addition, regular calibration by the manufacturer or an accredited body is customary, usually on a yearly cycle. This keeps the entire measuring chain, from microphone to display, verifiably accurate.
Carrying Out Noise Measurement to DIN EN ISO 9612
The aim of every noise measurement is to reflect the working reality as accurately as possible. DIN EN ISO 9612 provides three routes for this, from which you choose the one that suits your plant. All three lead to the same target value but differ in effort and suitability.
What matters is that the measurement reflects a representative working day. Outliers from an unusually quiet or particularly hectic day would distort the result.
The Three Measurement Strategies of the Standard
Three measurement strategies are distinguished by the standard, each oriented to the structure of the work. The overview below sorts them out.
| Measurement strategy | Principle | When suitable |
|---|---|---|
| Task-based | break the work into individual tasks and measure each task | clearly separable, recurring activities |
| Job-based | distribute samples across a function or job group | many similar workstations with changing routines |
| Full-day | continuous measurement across the whole shift | strongly fluctuating or hard to plan activities |
For each task the standard requires at least three measurements. If the results differ by more than 3 dB, further or longer measurements are needed to secure the spread.
Determining the Daily Noise Exposure Level LEX,8h
From the individual values the daily noise exposure level LEX,8h is calculated, normalising the entire shift to eight hours. This figure is the actual quantity against which the hazard is assessed.
The LEX,8h combines loud and quiet phases in energetic terms, weighted by their duration. A short, very loud task can carry more weight than a long, moderate exposure. This makes a person’s actual daily dose tangible, not just the peak value of a machine.
Measuring Noise Levels in Practice Step by Step
Measure the noise level in your plant along a fixed sequence so that the values stay comparable and traceable. A structured approach protects against typical slips and saves a lot of time in later repetitions.
The following steps have proven themselves in practice:
- Define the operating state and choose a representative, typical production run
- Determine measurement points, usually about one metre from sources and at ear height of the employee at the workplace
- Calibrate the device before the measurement series begins
- Set duration and repetitions per task according to the standard
- Document the boundary conditions, such as running machines, gates, ventilation and time of day
The more precisely these points are observed, the more reliable the result. A sound measurement without a note on the operating state can hardly be interpreted afterwards.
Setting Measurement Points and Duration
The choice of measurement points decides the significance of the result. At the workplace the level that counts is where the employee’s head is, not at the loudest spot in the hall.
Long enough must the measurement duration be to reflect fluctuating routines. For strongly varying activities, a longer measurement or the full-day strategy makes sense so that short load peaks and breaks are realistically included.
Avoiding Typical Measurement Mistakes
A common mistake is measuring on an untypical day, for example at half capacity. The values then come out too low and the exposure is underestimated.
Equally critical are reflections from badly placed microphones, a forgotten calibration or too short a measurement duration. Anyone who knows these pitfalls obtains values that every further planning step can rely on. When in doubt, it pays to have the measurement supported by specialists.
Creating a Noise Register and Mapping Your Plant
You create a noise register by bringing many individual measurements together into a spatial map of the plant. A collection of numbers thus becomes a vivid picture that makes noise hotspots instantly visible. This turns the register into the strategic tool for all further decisions.
Especially in large halls with many sources, such a map reveals connections that get lost in a plain table. You see at a glance which zones are critical and where employees need particular protection.
From Measured Value to Noise Map
On the floor plan the measured levels are shown as colour zones. Red areas mark high exposures, green zones mark uncritical values. This creates a noise map that is understandable even without acoustic expertise.
Such a presentation works excellently as a communication tool. Management, the safety officer and the workforce see the same picture and discuss on a common basis.
Identifying and Delimiting Noise Zones
On the basis of the map, noise zones can be clearly delimited and, where necessary, marked. Areas with high exposure can be fitted with access or hearing protection signs as long as technical measures are not yet in place.
The register is also the ideal comparison basis for later control measurements. After every conversion, a fresh map immediately shows whether the exposure has actually dropped.
What Belongs in a Noise Measurement Report
A clean noise measurement report is the proof that a measurement was carried out properly. It makes the results traceable and forms the basis for documenting the risk assessment. If the report is missing, even the finest readings are worthless.
At the same time, the documentation serves both internal assurance and evidence toward the supervisory authority. It should be complete and leave no room for interpretation.
Mandatory Details in the Measurement Report
A reliable report contains all the information needed to mentally repeat the measurement. The following details should not be missing:
- Instrument and class including serial number and calibration date
- Measurement points with position and height
- Operating state during the measurement
- Measured values per point and the calculated LEX,8h
- Measurement strategy and number of repetitions
- Measurement uncertainty plus date, time and name of the person measuring
The more complete these details are, the more robust the later assessment. A good report is still convincing years afterward.
When a New Measurement Becomes Due
A repeat of the measurement is always appropriate when conditions change. New machines, altered routines or a hall conversion can shift the exposure considerably.
Even without structural changes, regular review within the ongoing risk assessment is advisable. This keeps the picture current and the protective measures permanently matched to reality.
From Measurement to the Right Noise Control Solution
Measured values only unfold their value when the right measure is derived from them. This is exactly the interface where our work begins, because analysis for us is the start of every project and not a loose preliminary. From the levels, the frequency spectrum and the room situation, it follows whether a source should be enclosed or the reverberation in the room reduced.
If the measurement reveals a dominant single source, machine enclosures are often the most effective lever, because they contain the sound at the point of origin. If the exposure is spread across the whole hall, absorbing measures move to the foreground.
Precise Analysis as the Basis of Every Measure
For implementation we capture the on-site conditions to the millimetre with modern measuring equipment and a state of the art 3D scanner. This way every construction fits precisely and the planned effect actually occurs. Precise data becomes a solution that delivers in operation what the measurement promised.
If you would like specialist support with this step, we accompany you from the measurement to the finished measure. Discover our soundproofing solutions for industrial environments.
Frequently Asked Questions About Workplace Noise Measurement
At Which Noise Level Is Measurement Mandatory in a Plant?
As soon as a relevant noise exposure can be expected at a workstation, the employer must determine the exposure as part of the risk assessment. In practice this means that even the suspicion of critical levels triggers a measurement. The concrete action values are covered under the topic of workplace noise levels.
Which Standard Applies to Workplace Noise Measurement?
The relevant standard is DIN EN ISO 9612, which describes the procedure for determining the noise exposure level. It is an engineering method of accuracy class 2 and defines three measurement strategies. In addition, the German technical rules TRLV Lärm Part 2 give practical requirements for implementation.
What Is the Difference Between a Noise Measurement and a Noise Register?
A noise measurement determines the exposure at a workstation or a source. A noise register brings many such measurements together into a spatial map of the entire plant. The measurement therefore delivers the numbers, while the register makes them spatially visible.
Can You Measure Workplace Noise With a Smartphone App?
For a rough impression an app may do, but for the risk assessment it is unsuitable. Smartphones are not calibrated and do not meet the requirements of the measurement standards. Only calibrated sound level meters of the appropriate class provide legally sound values.
Who May Carry Out Workplace Noise Measurement?
Assign the measurement to competent people with suitable equipment and knowledge of the standards. These can be trained internal staff or external specialists. What matters is that the procedure, instrument class and documentation meet the requirements.
The Next Step for Your Plant
The path to noticeably less noise follows a clear order. First you measure the exposure properly, then you condense the values into the noise register, next you document everything in the report and derive the right measure from it. Each step builds on the previous one and none can sensibly be skipped.
Workplace noise measurement is not a task on the sidelines but the foundation on which every effective noise control rests. If you would like to approach this process in a structured way, we accompany you from the first measurement to the installed solution. Get in touch via our contact page and together we will find the right path for your hall.