Class 1 vs Class 2 Sound Level Meters in The Workplace – Which One is Best For You?

When working in noisy settings, whether that be a factory, airport construction site etc, it is crucial that workers are not exposed to loud noises for consistent amounts of time. This can be done through measuring the noise that they are exposed to through sound level meters.

Sound level meters come in all shapes and sizes, from your cheap amazon ‘Sound Level Indicators’ to the top of the range Class 1 sound level meter, so it’s important that you know the different tiers in the hierarchy of sound level meters. This is particularly important when dealing with Class 1 and Class 2 meters.

Class 1 and Class 2 meters are defined by international standards such as IEC 61672-1. The key distinction between the 2 levels is the precision of the meter:

Class 1 vs Class 2 – The Difference In Accuracy

In essence, Class 1 meters are much more accurate than Class 2 meters. This becomes clear when we look at the differences between the regulations that say what an acceptable amount of tolerance is when measuring noise at different frequencies.

At a 1kHz Reference Frequency, regulatory bodies expect the following range of accuracy in measurements.

• Class 1: ±0.7 dB
• Class 2: ±1.0 dB

As you can see, there is a larger range of accuracy for Class 2 meters. When dealing with legal cases, health of workers and more, it can become very important that accuracy is the highest it can be.  The discrepancy at a lower frequency of 20Hz grows more, we can see that a class 2 meter has over a 3dB difference in results.

• Class 1: ±2.5 dB
• Class 2: ±3.5 dB

And this difference only grows as frequencies get more extreme, at 16 Hz or 16 kHz the performance of Class 2 meters can significantly degrade, with tolerances exceeding ±5 dB or being undefined. Class 1 meters maintain tighter tolerances.

Accuracy, however, may not be of top priority when dealing with less demanding projects that don’t need as in-depth data or when a project may be on a tight budget. This is where a Class 2 meter may be of more use.

Other Features of a Class 1 Sound Level Meter

To meet the stringent standards for Class 1 compliance, there are plenty of features that are essential:

• Calibration adjustments at specific frequencies.
• Corrections for reflections, diffractions, and windscreens.
• Accurate directional response.
• Compliance with frequency weightings (A, C, etc.).
• Precise level linearity.
• Low self-generated noise.
• Time-weightings (Fast and Slow).
• Overload and under-range indications.
• C-weighted peak sound level measurements.
• Stability during continuous operation.
• High-level stability.
• Reset and threshold settings.
• Clear and reliable display.
• Analogue or digital output capabilities.
• Timing functions.
• Low radio frequency emissions and power supply disturbances.
• Reliable power supply performance.
• Environmental and electromagnetic tolerance, including:
  • Static pressure
  • Air temperature
  • Humidity
  • Electrostatic discharge
• Power-frequency and radio-frequency fields
• Mechanical vibration
• Auxiliary device compatibility.

Class 1 vs Class 2 – Practical Applications

The right meter depends on your workplace needs and legal requirements, if we look at a workplace setting where a team are exposed to harsh noise on a regular basis.

Workplace Noise (Control of Noise at Work Regulations 2005)

• Minimum Requirement: Class 2 meters.
• When to Use Class 1: For legal cases or detailed assessments where accuracy matters.

For more general noise monitoring, it is recommended that a class 1 sound level meter is used as it is not only good for making reports more reliable, it also future proofs your meter against further developments as your technology is better.

In essence,

• Class 2 Meters: Affordable and sufficient for routine noise checks.
• Class 1 Meters: A good choice if future-proofing or professional-grade precision is needed.

So, Which One Should You Choose?

For most workplace noise assessments, a Class 2 meter is sufficient. However, if you anticipate complex measurements or legal challenges, upgrading to a Class 1 meter is a smart investment.

Need Help Choosing?

We provide options for both Class 1 (SV 971A) and Class 2 (SV 973) meters to meet workplace noise monitoring needs. Check out our range of equipment to see what works best for you.