Hearing protection is a central topic wherever mineral materials are processed, separated, or deconstructed. In the application areas of Darda GmbH – from concrete demolition and building gutting to rock demolition and tunnel construction – working with concrete demolition shears, hydraulic splitter (wedge), hydraulic power packs, and other hydraulic tools generates noise levels that can burden the ear. The following article classifies the term professionally, explains the selection and use of hearing protection, and shows practical ways to control noise exposure in typical workflows – factual, precise, and without an advertising tone.
Definition: What Is Hearing Protection
Hearing protection is personal protective equipment that reduces the sound pressure load at the ear and thus lowers the risk of hearing damage. It works by attenuating sound energy – depending on the design, either broadband or frequency-dependent. In practice, earplugs (disposable or reusable), earmuffs (including helmet-mounted), and custom-molded otoplastics are used. Typical noise inputs around hydraulic shear (demolition shear), hydraulic splitter (wedge), and hydraulic power packs include continuous levels with low-frequency components and impulsive noises when gripping, cutting, or splitting concrete and rock. The goal is to lower the level reaching the ear so that work can be carried out safely and with sufficient communication – without over- or under-attenuation.
Types of Hearing Protection and Selection Criteria
Options include plugs, muffs, and custom-fitted systems. Plugs are lightweight and good in heat, but require correct fit. Muffs offer stable attenuation, are quick to put on and take off, and can be combined with site helmets as a helmet-mounted solution. Custom-molded otoplastics combine wearing comfort with reproducible attenuation. Important selection criteria include attenuation values (e.g., SNR and H-M-L), the noise frequency spectrum, impulse content, compatibility with helmet, safety glasses, and respiratory protection, communication needs, and hygiene requirements under dust, moisture, and long wearing times.
Noise Sources and Levels in the Application Areas
Noise arises from hydraulic drives, the gripping and breaking of concrete or rock, metal-on-metal contact, vibrations transmitted through structures, and impulsive events during cutting and splitting. In many situations, continuous sound levels are above the health-relevant range; individual impulses can be significantly higher.
Concrete Demolition and Special Demolition
- Concrete demolition shears produce impulsive noises when setting and breaking, combined with low-frequency noise from hydraulic power packs.
- Additional sources: separation cuts, lifting and transport operations, metal contact when exposing reinforcement.
Building Gutting and Cutting
- Combination shears and Multi Cutters cause fluctuating levels due to different materials (concrete, structural steel sections, conduits).
- Short, sharp impulses occur when cutting reinforcing steel or beams.
Rock Excavation and Tunnel Construction
- Hydraulic splitter (wedge) for rock and concrete act locally but generate distinct impulses and low-frequency components.
- In tunnel construction, reflections increase noise exposure; communication is more difficult.
Natural Stone Extraction
- Shift from quiet positioning to impulsive splitting; wind effects and topographic reflections change the sound field.
Special Demolition
- Steel-intensive tasks (e.g., with Steel Shears and tank cutters) generate high- and mid-frequency components as well as spark and contact noises that require high, impulse-robust attenuation.
Appropriate Hearing Protection by Task
The right solution depends on activity, duration, environment, and communication needs.
Working with Concrete Demolition Shears
- Recommendation: Earmuffs with good low-frequency attenuation; for high impulse content, combine plugs and muffs (double hearing protection).
- Important: Check helmet-mounting capability and tight seal even with safety glasses.
Use of Hydraulic Splitter (Wedge) for Rock and Concrete
- Because impulses can be short and forceful, uniform, impulse-robust attenuation is crucial.
- Consider double hearing protection when working in niches or shafts.
Hydraulic Power Packs in Close Proximity
- Low-frequency continuous levels from hydraulic power units require systems with strong attenuation in the lower frequency range.
- For operators who need to speak regularly, choose solutions with defined attenuation and high speech intelligibility.
Steel Shears and Tank Cutters
- Material fracture and metal contact produce sharp high-frequency content: use hearing protection with balanced H-M-L attenuation.
Multi Cutters and Combination Shears
- Varying materials require flexible solutions; where frequent donning and doffing is needed, muffs are practical.
Understanding Attenuation Ratings: SNR, H-M-L and Avoiding Over-Attenuation
The SNR value describes average attenuation across the frequency spectrum; H-M-L categorizes attenuation into high, mid, and low frequencies. In environments with hydraulic power packs, low-frequency components dominate – strong L attenuation is useful here. For impulse-rich tasks with concrete demolition shears and hydraulic splitter (wedge), balanced H and M attenuations are important. Too much attenuation can render warning signals inaudible and cause miscommunication; the goal is needs-based reduction, not maximum isolation.
Wearing Comfort, Communication, and Warning Signals
Longer use requires comfortable, sweat-resistant systems that also enable communication and recognition of warning signals. In dusty, warm, or humid environments, skin compatibility matters; smooth, cleanable surfaces support hygiene. For teamwork, solutions that transmit speech better or – if needed – accept communication technology are useful, as long as protection is maintained.
Combination with Other PPE
- Helmet-mounted muffs ensure compatibility with safety helmets.
- Lower-profile eyewear temples make it easier to maintain a tight seal alongside respiratory protection and safety glasses.
- With respirators, carefully ensure seal and proper contact surfaces.
Measurement, Documentation, and Training
Responsible persons define suitable measures based on measurements or well-founded estimates of noise exposure. These include selecting appropriate hearing protection types, clear wearing times, training, and regular effectiveness checks. Portable measuring devices and dosimeters help capture typical daily exposures and align them with work phases (e.g., cutting, splitting, transport).
Hazard Analysis
- Structure activities (e.g., positioning the concrete demolition shear, breaking phase, placement).
- Consider frequency components and impulses.
- Translate the result into practical instructions for the crew.
Fit and Seal
- Plugs require correct insertion; brief training significantly increases protective effect.
- For muffs, check headband force and cushion condition; replace worn cushions.
Care, Hygiene, and Replacement Intervals
Clean, intact hearing protection attenuates reliably. Clean plugs regularly or – if disposable – replace consistently. Inspect muff cushions and sealing rings; replace if cracked or hardened. In dusty environments, store hearing protection in clean containers. For shared muffs, provide hygiene covers or clear cleaning plans.
Organization: Low-Noise Workflows and Break Planning
Organizational measures further reduce exposure. These include spatial separation of personnel and hydraulic power packs, bundling noise-intensive steps, rotating duty schedules, and planned rest periods. Indoors, decoupling pads and avoiding unnecessary metal contact help. In tunnel construction, a precise sequence of work steps is important to limit echo effects and multiple exposures.
Special Aspects in Tunnel Construction and Special Demolition
Tight spaces and sound reflections increase perceived loudness. Here, double hearing protection is often appropriate for impulse-rich tasks. Communication must still work safely: clear hand signals, defined radio windows, and acoustically redundant warning signals (supplemented visually) are proven.
Typical Mistakes and Better Solutions
- Putting on hearing protection too late: don hearing protection before the first impulsive event.
- Incompatible combinations with safety glasses: check sealing lines; if necessary, choose models with slimmer temples or helmet-mounted muffs.
- Focusing only on SNR: consider H-M-L and the actual frequency spectrum.
- Worn cushions: replace early, otherwise attenuation drops significantly.
Legal Classification (General, Non-Binding)
Recognized rules of occupational safety typically apply to workplace noise. There are trigger values at which the employer implements protective measures, provides hearing protection, and ensures training. For high exposures, further steps are necessary. Details depend on the applicable law and relevant standards; company-specific assessments remain decisive.
Relation to Products and Application Areas of Darda GmbH
The noise characteristics of the tools directly influence the choice of hearing protection: concrete demolition shears generate short, high-energy impulses when breaking structural elements; hydraulic splitter (wedge) for rock and concrete produce impulse and low-frequency components during splitting; hydraulic power packs shape the low-frequency foundation; steel shear and tank cutters create sharper high-frequency components when cutting. In the areas of concrete demolition and special demolition, building gutting and cutting, rock excavation and tunnel construction, natural stone extraction as well as special demolition, the selection, wearing method, and care of hearing protection should be adapted to these profiles so that safety, communication, and work quality reliably come together.