12 April 2022
On hazardous sites with harmful noise levels, the requirement for adequate hearing protection can be at odds with the need for effective communication. Louise Charlton explores how new technology is changing the way teams communicate in high-noise environments.
HIGH-LEVEL noise damages the hearing, leading to life-changing conditions such as noise-induced hearing loss (NIHL) and tinnitus. The Labour Force Survey (LFS) reported an estimated 14,000 UK workers with work-related hearing problems in 2018/19 – 2020/21. Construction is highlighted by the HSE as a particularly high-risk sector for hearing damage, along with demolition, roadworks and forestry. Noise control in these applications presents a complex challenge. Controlling exposure means blocking noise out, which makes communication difficult and reduces situational awareness.
Where a job allows, noise zones or areas of refuge can be set up. Enclosing noise to hearing protection zones free from moving hazards, or designating areas where noise is excluded, can enable effective use of passive hearing protectors. When safe working practices rely on communication and detection of approaching hazards, however, passive protection may be unsuitable.
Communicating in high-noise environments is difficult in itself and can become impossible with passive hearing protection. Downtime increases to enable safe communication away from noise hazards or with machines switched off. Efficiency is further reduced as mistakes result from misunderstandings, and the impacts of low morale and isolation among wearers who are disconnected from their surroundings.
It is important to remember that, as a long-latency hazard, hearing damage can go unnoticed for many years before presenting as a hearing condition later in life. Wearers may remove PPE temporarily to communicate, or work in a hazardous area, and in doing so unknowingly increase exposure above safe limits.
Injury rates in construction are significantly higher than other industries, with fatal injuries around four times the all-industry average (RIDDOR 2016/17 – 2020/21). The top causes of fatal injuries in construction, after falls from a height which accounted for 50%, were becoming trapped by something collapsing or overturning (13%); being struck by a moving, flying, or falling object (11%); being struck by a moving vehicle (10%); and contact with moving machinery (4%). These figures highlight the importance of situational awareness on site. To minimise risk and reduce these types of injuries, the workforce must be able to communicate effectively and remain aware of their surroundings.
With construction posing elevated risk of both hearing damage and injuries, noise must be controlled without impeding situational awareness or limiting communication. On hazardous sites with moving vehicles and machinery, passive hearing protectors introduce additional risks. Wearers are unable to hear approaching vehicles and warning sounds to avoid collision or crushing hazards. In some cases, PPE is removed or fitted incorrectly to remain safe from other hazards. This shows equipment has not been properly assessed for suitability and does not meet the needs of the workforce. While the requirement for hearing conservation is better understood than in the past, when work environments demand choice between risking injury from heavy vehicles or sustaining latent hearing damage it is easy to appreciate how ear defenders could be considered lower priority.
In addition to immediate accident risk, reduced situational awareness has further impacts over time. Difficulty interpreting speech and locating sounds puts increased pressure on cognitive functions, causing fatigue. Studies show that impairment of speech-in-noise recognition and sound source localisation abilities accelerated cognitive fatigue in wearers of unsuitable hearing protectors (The Effect of Hearing-Protection Devices on Auditory Situational Awareness and Listening Effort, Smalt et al. 2020). Increased cognitive fatigue means a tired workforce, who are unable to focus and at higher risk of injury from machinery and moving hazards.
Two-way radio offers medium-range communication at distances of 3km and over, depending on wattage. These headsets are common and compatible with other devices. As the name suggests, two-way radio is limited to two users and does not allow teams to communicate as a group. Radio communication is half duplex, meaning only one user can transmit while another receives. Using two-way radio can make it time-consuming to get instructions out to a workforce, and messages can be cut off if transmissions clash. Audio quality is low, making it difficult to interpret speech against background noise. Another limitation is the need to press a button to speak. Push-to-talk systems mean wearers must down tools to communicate safely, which impacts on efficiency and can pressure wearers to find unsafe ways to operate headsets without pausing work.
Wireless short-range systems allow groups to communicate in full duplex, with some options supporting hands-free speech. Up to seven devices can connect, but networks can be patchy, and range is extremely limited. Overall distance can be 50m or less, with some products offering just 10m. Network strength is weakened as more users are added, and often 3-4 devices is a more realistic group size for a good connection. Another frequent problem with short-range wireless is the network structure. With conventional ‘daisy-chain’ style systems, if one user moves out of range the entire group is disconnected. This limits a team’s ability to move around and prevents users leaving and re-entering range without disrupting comms for the team.
Cellular and LTE systems offer long-range full duplex group communication, allowing groups of 10+ people to connect at a theoretically infinite range. As with short-range wireless comms, group size is limited by network quality. Larger groups experience weaker connections, and group connection is dependent on the signal strength of each device. With the long range users can move around but, due to network structure, connection is lost if one or more devices drop out. The system is entirely dependent on overall network quality and availability. An unexpected outage, or remote site with no coverage means no comms.
Where team communication is critical, technology must be robust. Undeveloped and remote sites without internet or mobile coverage require communication technology that operates at appropriate range without relying on external connectivity. Wearers need a high degree of situational awareness and freedom to move around to work safely. Communication and hearing protection solutions must meet the complex needs of the workforce in order to improve safety without reducing efficiency.
Level-dependent hearing protectors incorporate microphones which detect external sound levels to provide active protection. Headsets amplify safe ambient sounds, allowing the wearer to hear low-level background noise, then, when the circuit detects high noise, the system shuts off to provide attenuation. This protects against hearing damage while allowing wearers to communicate verbally, hear warning signals and detect approaching hazards. Level-dependent systems with integrated comms enable wearers to communicate verbally with colleagues nearby and at a distance.
Headsets with stereo audio and directional sound help to preserve situational awareness and minimise cognitive fatigue. High quality playback recreates the external environment, making it easy to detect the source of sounds and distinguish different tones.
Voice-recognition software detects and isolates speech for enhanced communication in noisy environments. Background noise is cut out to make transmissions clear and easy to understand.
Self-hearing features provide audio feedback, enabling the wearer to hear their own speech. The attenuation provided by hearing protectors makes speech muffled or inaudible, which can be disorientating and mean the wearer is unsure whether they can be heard properly by others. By picking up and amplifying speech within the headset, self-hearing makes communication feel more natural and provides confidence that speech is transmitted clearly.
New autonomous intercom technologies provide an independent connection, breaking down barriers to communication on remote and undeveloped sites. These systems create a robust network that operates without internet or cellular coverage, unsusceptible to outages and ideal in locations with no existing infrastructure.
Dynamic network structures maintain group connection while users move in and out of range. Headset devices each emit a signal, creating a network that heals itself as teams move around. With this type of technology, group connection is strengthened with each device added, meaning network strength improves as team size increases. Systems with ranges up to 3km allow teams to spread out and stay connected across large sites.
Safer working practices
Hearing protection with the latest technology enables clearer, more effective team communication. Full duplex support means transmissions are clear and complete, with no lost or clashed messages. The fluid, conversational communication style allows everyone to clarify instructions and ask questions. Wearers can speak during another transmission, which is vital when there is time-critical information to communicate.
Medium-range hands-free technology encourages safer working practices. By facilitating effective team comms without downing tools, hands-free technology can improve safety and efficiency. It helps to prevent accidents and injuries, prioritising easy communication across large sites without affecting productivity, meaning workers no longer have to choose between getting the job done quickly and working safely. Fully hands-free headsets allow wearers to speak, make calls, and adjust settings using voice activation for complete control on the job.
Built-in emergency functions enable wearers to call for assistance. Intercom alerts to contact teammates and speed-dial emergency calling ensure help is always on hand.
To combat hearing damage without introducing additional risk, effective communication and situational awareness must be assessed as important suitability factors when selecting hearing protection. Passive protectors can be used effectively where the job allows but may be unsuitable in hazardous areas. Two-way radio, cellular and short-range wireless headsets enable communication but force compromises on range or reliability. Innovative new technology is changing the way teams communicate on site. Autonomous systems open up remote locations, providing robust, dynamic networks that allow large teams to stay connected over several miles rather than metres. Integrated level-dependent attenuation with high quality audio playback helps to preserve situational awareness. New technology is connecting sites for high-performance hearing protection and unlimited communication without compromise.
Louise Charlton is technical copywriter at JSP Safety. For more information, visit www.jspsafety.com