Cirrus Diagnostic: Find the Right Sound Level Meter in 2 Minutes

Cirrus Research

The Cirrus Diagnostic

Answer these questions to get an indicative estimate of your noise exposure level and a recommendation for the right Cirrus equipment for your needs.

⏱ 2 minutes · Free

What sector do you work in?

This helps us tailor the recommendation to your work environment.

What's your main need?

Several uses may apply, but choose the most frequent one.

What is the usual noise level in your environment?

A rough estimate by ear is fine, no need to be precise.

How long per day are your employees exposed to this noise?

Cumulative duration during the working day.

Recommendations are based on your answers and regulatory exposure values (UK Control of Noise at Work Regulations 2005). The LEX,8h estimate is indicative and does not replace a certified measurement.

Learn more about the Cirrus Diagnostic

How does the Cirrus Diagnostic work?

The Cirrus Diagnostic is a free tool that helps businesses assess their noise exposure at work and meet their regulatory obligations (Control of Noise at Work Regulations 2005, and workplace risk assessment documentation). By answering 4 questions about your sector, your need, the usual noise level and your employees' daily exposure duration, the tool calculates an indicative estimate of LEX,8h (daily personal noise exposure level) and recommends the Cirrus Research sound level meter or noise dosimeter best suited to your situation. This estimate is indicative and does not replace a measurement taken by a professional with a certified instrument.

What is LEX,8h?

LEX,8h (daily personal noise exposure level) is the standard measure used to compare a worker's noise exposure to an equivalent 8-hour working day, regardless of actual shift length. It's the figure checked against the UK's three regulatory action values: 80 dB(A), 85 dB(A), and the 87 dB(A) exposure limit value. A noise dosimeter worn by the employee, or a calibrated sound level meter reading combined with exposure duration, is used to calculate it.

What is the noise exposure limit at work?

Under the Control of Noise at Work Regulations 2005, the exposure limit value is 87 dB(A) averaged over 8 hours, with a peak limit of 137 dB(C). Employers must provide hearing protection once exposure reaches the lower action value of 80 dB(A), and its use becomes mandatory at the upper action value of 85 dB(A).

Why measure noise at work?

Measuring noise is a legal duty for employers and local authorities whenever sound levels could pose a risk to hearing or the surrounding environment. Employers must assess exposure once it reaches 80 dB(A) and act once it exceeds 85 dB(A). For sites affecting the public, environmental noise assessments also help councils meet their obligations. Cirrus Research has supported these assessments since 1970 with Class 1 and Class 2 certified sound level meters and noise dosimeters, backed by a UKAS-accredited calibration laboratory.

Which sectors does the Cirrus Diagnostic cover?
  • Industry & Logistics (factory, warehouse, production, handling)
  • Construction / Building sites
  • Local authorities (council, city, public space)
  • Occupational health (occupational physician, health & safety services)
  • Hospital / Clinic
  • Consultancy (acoustics, control, regulatory verification)
  • Transport / Vehicles
  • Education / Research (university, school, laboratory)
Who is responsible for measuring noise in the workplace?

The employer is legally responsible for assessing workplace noise risk, though the measurement itself is often carried out by an HSE manager, an occupational health provider, or an external acoustic consultant for a legally binding report. Whoever performs the assessment, the instrument used must be calibrated and traceable to a recognised standard.

How often should noise levels be measured or reviewed?

Noise measurements should be reviewed whenever the work environment, equipment or processes change significantly, and periodically as part of ongoing risk assessment. Instruments themselves should be sent for calibration annually to remain compliant and traceable, and checked with an acoustic calibrator before and after each use.

Class 1 vs Class 2 sound level meter: what's the difference?

A Class 1 sound level meter offers higher measurement accuracy and is required for legally binding reports, environmental noise assessments, or situations that may be challenged, such as noise nuisance disputes. A Class 2 meter is accurate enough for routine internal workplace checks and day-to-day compliance monitoring. Most Optimus+ sound level meters are available in both classes depending on your need.

What's the difference between a sound level meter and a noise dosimeter?

A sound level meter measures noise at a fixed point, such as a workstation or site boundary, and suits one-off assessments or environmental monitoring. A noise dosimeter is worn by an individual throughout their shift to measure personal cumulative exposure, essential when workers move between noisy areas or operate machinery like forklifts. Many assessments use both together: see our Safety Officer's Kit for a combined solution.

Does environmental or neighbourhood noise need to be measured too?

Yes. Local authorities and businesses can be required to measure and monitor environmental noise when it affects nearby residents, whether from a construction site, an event, road traffic, or a nuisance complaint. Continuous monitoring solutions like Quantum Outdoor or a Trojan noise nuisance recorder are commonly used for these longer-term, unattended assessments.

Which noise measurement instrument should I choose?

The choice depends on three things: what you need to measure (a workstation, an employee's individual exposure, or a site's environmental noise), the level of precision required (Class 1 for a legally binding report, Class 2 for routine internal checks), and whether the measurement is one-off or needs continuous monitoring. Most Optimus+ sound level meters are available in both classes. For a personalised answer to your situation in 2 minutes, the Cirrus Diagnostic at the top of this page recommends the right instrument for your sector and need directly.

Which Cirrus Research products could I be recommended?
What analysis software is included with Cirrus Research instruments?

Every sound level meter and doseBadge dosimeter comes with NoiseTools, a licence-free software included at no extra cost. It lets you download, analyse and report your measurements, generate regulatory reports, and get recommendations for the right hearing protection based on your results.

What warranty do Cirrus Research instruments come with?

Cirrus Research instruments carry a 15-year warranty, provided the instrument is calibrated in line with the manufacturer's recommended schedule. This long-term cover reflects the durability of our instruments and the importance we place on regular calibration to keep your measurements accurate and traceable.

Who is Cirrus Research?

Since 1970, Cirrus Research has designed and manufactured noise and vibration measurement instruments, including sound level meters, noise dosimeters and environmental noise monitors. The company operates a UKAS-accredited calibration laboratory and offers the licence-free NoiseTools analysis software. Our team of noise measurement experts responds quickly to quote requests.

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