Published July 2, 2026 at 07:33
Hearing loss due to occupational noise exposure is one of the most common, most preventable, and at the same time most underreported occupational injuries in Sweden. Prevention is simple when the sound level is known — but ”known” doesn’t mean someone thinks it sounds loud. It means measured, documented, compared against the legal limits. The Swedish Work Environment Authority’s regulation AFS 2005:16 is unambiguous: above 80 dB(A), hearing protection is recommended; above 85 dB(A), the employer is obliged to provide hearing protection and implement measures; and above 87 dB(A) at 8 hours of exposure, there is no excuse left. Without a measuring instrument, all these limit values are just numbers.
What ”Class 2” actually means
Sound level meters are classified according to IEC 61672 into Class 1 and Class 2. Class 1 is the precision instrument — accuracy within ±0.7 dB, used by professional acousticians for regulatory investigations and new-installation measurements. Class 1 instruments cost from SEK 15,000 and up. Class 2 has ±1 dB accuracy — entirely sufficient for the monitoring measurements the Swedish Work Environment Authority requires of employers at their own workplaces. The AFS 2005:16 regulation explicitly names Class 2 as an acceptable standard for self-monitoring.
The Mini SL510 sound level meter meets Class 2 (IEC 61672-2013 and ANSI S1.4 Part 1) with ±1 dB accuracy across a measuring range of 35–130 dB. That covers everything from a quiet office (35–45 dB) to a workshop environment next to a hammering machine (110–130 dB). The display is backlit so readings work even in poorly lit production halls.
A-weighting vs. C-weighting — and why both exist
A sound level meter doesn’t simply measure sound pressure in air. It measures it weighted through a filter that mimics the human ear’s sensitivity to different frequencies. The ear is most sensitive to mid-range frequencies (500–4,000 Hz) and less sensitive to very low or very high frequencies. A-weighting applies this filter, which is the standard for most work environment measurements and the standard referenced by the Swedish Work Environment Authority. The result is expressed as dB(A).
C-weighting provides a flatter frequency response — closer to what a protected ear actually experiences, including low frequencies. The difference between A- and C-weighting on the same measurement reveals whether the sound is dominated by low-frequency components — critical for assessing which type of hearing protection is effective. If the A-C difference is large (e.g., 8 dB), the sound is dominated by low-frequency rumble, and foam earplugs aren’t sufficient protection; earmuffs are needed.
Fast vs. slow response time — which should you choose
The instrument offers both fast (Fast, 125 ms integration) and slow (Slow, 1 s integration) measurement. Fast measurement captures short impulses — a hammering machine striking at 2-second intervals shows up as peak values on Fast. Slow measurement gives a time-weighted average level, which is closer to what the ear actually experiences over time and the measurement the law requires to be documented.
Practical routine: always measure with Slow for documentation, and supplement with Fast to identify specific noise spikes that should be addressed separately.
Where the meter is used in practice
Workshop industry: Baseline measurement of noise levels at different workstations — lathe, milling machine, drill press, CNC cell. The difference in dB(A) between the operator’s position and adjacent stations determines local noise-reduction needs.
Construction sites: Continuous monitoring of noise from various machines — nail guns, circular saws, demolition hammers, compressors. Many of these exceed 110 dB — far above the hearing-damage threshold — and require documented exposure calculations.
Commercial kitchens and restaurants: Dishwashing areas, chef workstations, and dining areas. High noise levels are not just a work environment issue but also a guest-experience issue, and measurement is the only way to make the case for acoustic improvements.
Schools and preschools: Classrooms, gymnasiums, dining halls. High noise levels in classrooms affect both teachers’ health and students’ learning.
HSE departments: Routine monitoring of noise levels as part of systematic work environment management. A simple measurement as part of regular safety inspections.
Music and entertainment industry: Sound levels at mixing consoles, in rehearsal spaces, on concert stages. The Swedish Work Environment Authority’s rules apply here too — musicians and sound engineers have the same right to hearing protection as workshop workers.
What you get for the money
Measuring range 35–130 dB, ±1 dB accuracy, A- and C-weighting, Fast and Slow response time, Data Hold, Min/Max functions, auto power off (can be disabled), tripod mount (tripod sold separately), supplied with a microphone windscreen, wrist strap, and three AAA batteries.
SEK 2,500 is an investment that makes the Swedish Work Environment Authority’s systematic work environment management practically achievable without outside consultants. For HSE departments and supervisors at smaller companies, it’s often the only way to go from ”we think it’s fine” to ”we’ve measured and documented it”.
Read more: Mini SL510 sound level meter in the shop →
