Machinery Noise Surveys
Operator position
Real working layout
Source data
Machine contribution
Cycles & load
Representative running
Machinery noise measurement
Operator & source data
What it is
What a machinery noise survey assesses
A machinery noise survey is a source-focused occupational assessment of an individual machine, cell or group of machines. Unlike a whole-area factory survey, it concentrates on how a specific machine contributes to operator exposure, what its dominant noise mechanisms are and what can be done to reduce them.
Machinery surveys are particularly useful at the points where decisions about noise are actually made: at purchase, at commissioning, when designing controls, after installing controls and when investigating why operator exposure is higher than expected. They give clear, machine-specific evidence rather than averaged area data.
The survey is delivered under the Control of Noise at Work Regulations 2005 and is complementary to broader factory noise surveys, workplace noise surveys and workplace noise monitoring.
When you need a survey
When machinery measurements are required
- New machinery is being commissioned
- An existing machine has been modified
- Manufacturer-declared data needs verification in workplace conditions
- Engineering controls are being designed
- Controls have just been installed and need verification
- A specific machine appears to dominate operator exposure
- Operator complaints have been raised about a particular machine
- Quieter purchasing options are being evaluated
- A machine is being relocated within the workplace
- Duty cycles or production rates have changed
Operator position
Operator-position measurements
Operator-position measurements reflect what the operator actually experiences in the installed layout.
- Head-height measurement at the working position
- Multiple positions where the operator moves
- Time-weighting across positions
- Capture during representative cycles
- Includes set-up and changeover where relevant
- Cross-checked against dosimetry where available
Source measurements
Source measurements
Standardised measurements around the machine support comparison with manufacturer-declared data and engineering design decisions.
- Measurements at standard 1 m positions
- Multiple measurement positions around the machine
- Hemispherical sampling where appropriate
- Background-noise correction
- Operating load and product mix recorded
- Comparison with manufacturer-declared values
Machine cycles
Machine cycles and operating load
Noise varies through the machine's cycle. Measurements capture each significant phase at the actual operating load.
- Set-up and start-up
- Idle and ready
- Productive run at typical load
- Productive run at peak load
- Tool engagement and disengagement
- Changeover and product changes
- Shut-down and cool-down
- Maintenance interventions during the shift
Multiple machines
Multiple-machine interaction
When several machines run together their noise combines; the survey captures realistic combinations rather than single-machine isolation.
- Simultaneous operation of nearby machines
- Background contribution from surrounding equipment
- Acoustic cross-coupling within the cell
- Shared services (compressors, extraction) contribution
- Workpiece-handling between machines
- Realistic combined operator exposure
Peak & impact
Peak and impact noise
Peak sound pressure (LCpeak) is assessed separately from average exposure. Short events can exceed the peak action value (135 dB(C)) or peak limit value (137 dB(C)) even when time-averaged exposure looks moderate.
- Pressing and stamping operations
- Forming and forging
- Tooling impact at entry and exit
- Workpiece ejection from machines
- Pneumatic discharge bursts
- Material handling on bed plates
- Crash-stop events during faults
Compressed-air noise
Compressed-air noise
Compressed-air discharge is one of the most common — and most controllable — contributors to machinery noise.
- Cycle-end air discharge
- Part-clearance air blasts
- Pneumatic ejection
- Open-pipe air-line cleaning
- Air-line leaks at fittings
- Excessive supply pressure
- Worn or wrong-specification nozzles
Vibration
Vibration and structural transmission
Vibration through mounts and structure can support tonal noise and radiate from panels and ductwork.
- Vibration through machine feet and mounts
- Resonance in panels and guards
- Vibration via piping and ductwork
- Workpiece resonance during cutting
- Out-of-balance rotating equipment
- Loose components and fixings
Guards & enclosures
Guards and enclosures
Guards and enclosures both protect operators from mechanical hazards and influence noise. Their condition has a material effect on operator exposure.
- Acoustic performance of factory-supplied guards
- Damping condition of panels
- Seal integrity around access doors
- Gaps and openings that bypass enclosures
- Maintenance windows used in production
- Damaged or removed acoustic guarding
- Lined versus bare interior surfaces
Maintenance condition
Maintenance condition
Machinery noise commonly rises as components wear. The survey can identify machines that warrant maintenance attention.
- Worn bearings and drives
- Worn cutting tooling and inserts
- Loose panels and guards
- Damaged or degraded silencers
- Imbalance in rotating equipment
- Compressed-air leaks
- Worn isolation mounts
- Poor lubrication
Commissioning
New-machinery commissioning
Measurements at handover establish a baseline, verify supplier claims and identify issues before the machine enters routine production.
- Operator-position measurement at handover
- Source measurement around the machine
- Comparison with declared noise emission
- Verification of installed controls
- Baseline for future re-measurement
- Identification of remedial work before sign-off
Supplier data
Supplier noise data versus workplace conditions
Manufacturer-declared values are obtained under standard test conditions and rarely match real-workplace exposure once layout, room acoustics, workpiece and cycle are included.
- Declared sound power versus measured sound pressure
- Standard test versus real workpiece
- Free-field versus reverberant room
- Single machine versus multiple machines
- Idle declared values versus loaded operation
- Need for in-situ verification
Machinery & exposure
Machinery and employee exposure
Machinery measurements feed into broader employee exposure assessment — see noise exposure assessment and personal noise dosimetry for the wider picture.
- Identification of dominant exposure sources per worker group
- Operator-position values for SEG assignment
- Cycle-weighted operator exposure
- Combined exposure across multiple machines per shift
- Cross-check with dosimetry data where available
Task duration
Task duration
Daily duration has as much effect on exposure as instantaneous level. Realistic durations are recorded from observation and operator input.
- Observed cycle times under typical production
- Operator-reported task durations
- Set-up and changeover durations
- Maintenance interventions during the shift
- Breaks and machine idle time
- Realistic LEX,8h calculation
Control opportunities
Control opportunities
Recommendations are framed against the specific machine, not catalogue solutions. Wider context in our Noise Control Measures in Industry guide.
- Improved or replacement acoustic guarding
- Damping on panels and casings
- Silencers and diffusers on air discharge
- Quieter nozzles in place of open lines
- Vibration isolation of feet and mounts
- Workpiece supports to reduce resonance
- Modification of tooling impact at entry/exit
- Local screens around the operator position
- Sequencing to limit concurrent peak events
Quieter purchasing
Quieter purchasing
Specifying noise performance at purchase is one of the most effective forms of control available — and one of the cheapest, if done up front.
- Noise emission limits in specifications
- Requesting declared sound-power data
- Site-visit measurement of candidate machines
- Verifying performance at handover
- Including acceptance criteria in contracts
- Treating noise as a procurement criterion alongside output and cost
Verification
Verification after controls
After controls are installed, repeat measurement is essential to confirm they perform as expected and to set a new baseline.
- Re-measurement at operator and source positions
- Comparison with pre-control baseline
- Verification under representative load
- Confirmation of peak and tonal performance
- Identification of any residual issues
- Updated record for the noise risk assessment
Survey process
How a machinery survey is delivered
- 1
Initial consultation
Discussion of machines, objectives, operating context and survey scope.
- 2
Information review
Review of machine documentation, declared data and any prior measurements.
- 3
Site visit
Visit timed to capture representative running conditions.
- 4
Walkthrough
Documented observation of the machine, operator interaction and surrounding equipment.
- 5
Measurement plan
Plan covering operator, source, cycle and peak measurements.
- 6
Calibration
Pre- and post-measurement acoustic calibration of all instrumentation.
- 7
Operator-position measurements
Measurement at the actual working positions during representative cycles.
- 8
Source measurements
Standardised measurements around the machine.
- 9
Cycle and load capture
Measurement across set-up, run, peak load and changeover.
- 10
Operator discussion
Brief input from the operator and supervisor on typical duty patterns.
- 11
Data validation
Quality review of captured data and operating conditions.
- 12
Exposure interpretation
Operator-position and peak interpretation against CNWR 2005 action and limit values.
- 13
Control recommendations
Practical, prioritised actions for the machine.
- 14
Technical report
Clear written report covering scope, methods, findings and recommendations.
Deliverables
What the client receives
- Documented scope and methods
- Operator-position measurement results
- Source measurement results
- Cycle and load characterisation
- Peak sound-pressure findings
- Comparison with manufacturer-declared data
- Operator exposure interpretation
- Identification of dominant noise contributors
- Practical engineering control recommendations
- Quieter-purchasing input where relevant
- Verification baseline for future re-measurement
- Clear written technical report
Machinery supported
Machinery types supported
Machinery noise surveys across a wide range of UK industrial equipment, including:
CNC machining centres
Presses & stamping
Production lines
Grinders & finishers
Packaging machinery
Bottling & filling
Process equipment
Custom-built machinery
Common mistakes
Common assessment mistakes
- Relying only on manufacturer-declared noise data
- Measuring at one cycle phase only
- Ignoring peak and impact events
- Measuring an isolated machine when it normally runs with others
- Not recording realistic operating load
- Missing compressed-air discharge
- Treating supplier source values as operator exposure
- Not re-measuring after controls have been installed
- Treating quieter purchasing as optional
- Using consumer phone apps as measurement tools
Why us
Why choose Workplace Noise Surveys
Source-focused
Surveys built around the specific machine and how it actually runs in production.
Operator-centred
Operator-position measurements grounded in real working layouts.
Cycle-aware
Set-up, run, peak load and changeover all captured rather than averaged away.
Peak and impact covered
Short-duration high-level events quantified directly.
Practical control focus
Engineering recommendations framed for the machine, not generic catalogue lists.
UK regulatory framing
Findings reported against the Control of Noise at Work Regulations 2005.
Related services
Connected services and guidance
Related services: factory noise surveys, noise exposure assessment, workplace acoustic surveys, hearing protection assessment, noise at work regulations and occupational hygiene noise services.
Background reading: our How Workplace Noise Is Measured guide.
FAQ
Machinery noise survey FAQs
What is a machinery noise survey?+
A machinery noise survey is a source-focused occupational assessment of an individual machine or group of machines. It quantifies sound levels at the operator position, around the machine and during representative cycles, identifies the dominant noise contributors, assesses peak and impact events and supports decisions on engineering control, hearing protection and quieter purchasing. Findings are interpreted under the Control of Noise at Work Regulations 2005.
How is this different from a factory noise survey?+
A factory noise survey covers a whole production environment and the workers within it. A machinery noise survey is narrower: it focuses on individual machines and how their operation contributes to operator exposure and area noise. The two are complementary — a factory survey establishes overall exposure while a machinery survey supports targeted control of specific sources.
When are machinery noise measurements required?+
Machinery measurements are commonly carried out when new equipment is being commissioned, when modifications have been made, when suppliers' declared noise data needs verification in real workplace conditions, when controls are being designed, after controls have been installed (to verify their effect), and where individual machines are suspected of driving overall exposure.
Can supplier noise data be used instead of measurement?+
Manufacturer-declared noise emission data is useful at the point of purchase but it is rarely sufficient on its own to characterise exposure in a real workplace. Declared values are obtained under standard test conditions that do not reflect specific operating loads, workpiece resonances, room acoustics or the interaction of multiple machines. Workplace measurement is needed to confirm what operators actually receive.
How is the operator position defined?+
The operator position is the location the operator occupies while controlling or attending the machine, typically at head height. Where operators move between several positions during a cycle, measurements are taken at each, and time-weighted to reflect the time spent at each position.
Are source measurements at the machine the same as operator-position measurements?+
No. Source measurements are taken at standardised distances and positions around the machine to characterise its emission, while operator-position measurements reflect what the operator is exposed to in the actual layout. Both can be useful: source measurements support comparison with declared data and design decisions; operator measurements support exposure assessment.
How are machine cycles and operating load handled?+
Most production machinery has distinct phases — set-up, run, idle, change-over — and noise levels differ between them. The survey captures measurements during representative cycles at the actual operating load and product mix, then weights them by typical duration to give a fair picture of operator exposure.
What happens when several machines run together?+
When multiple machines run at the same time their noise combines, and the dominant exposure source for a given worker may not be the machine they operate. The survey accounts for this by measuring representative combinations and by characterising background noise from surrounding equipment, so individual machine contributions can be put into context.
Are peak and impact events assessed?+
Yes. Peak sound pressure (LCpeak) is assessed separately from time-averaged exposure. Presses, stamping, hammering and pneumatic discharge can all exceed the peak action or limit values even where average exposure is moderate. These events are quantified explicitly during the survey.
Can the survey support new machinery commissioning?+
Yes. Commissioning measurements at handover provide a baseline against manufacturer-declared values, identify whether installed controls are performing as expected and inform any operator-position adjustments before the machine enters routine production. Commissioning data is also useful as a reference point for future re-measurement.
Will the report recommend specific noise controls?+
Yes. The report sets out practical, prioritised noise-control opportunities relevant to the specific machine — guarding, enclosure, damping, isolation, silencers, workpiece supports, modifications to compressed air or maintenance attention. Recommendations are framed around what is reasonably practicable for the equipment and its production role.
How often should machinery noise be re-measured?+
Machinery noise should be re-measured when there is a material change — modification, relocation, increased duty cycle, changed product mix or installation of controls — or where the existing assessment is more than around three to five years old. Re-measurement after control installation is essential to verify performance.