How to Better Manage the Risks During Excavation | 15th May 2019
Health and safety risks during excavation include falls (e.g. from one level to another), falling objects, fall or collapse of rock, vibration and dangerous noise levels and exposure to airborne and environmental contaminants. In addition, we have to consider the underground power, water, gas, sewerage and telecommunications lines. Accidentally hitting those underground lines could cause electrocution, health hazards and injuries.
To better manage the risks during excavation requires considering the safety of the workers, the passersby and the people near the excavation site. Notice that in the health and safety risks mentioned above (such as falls and falling objects) they can affect both the workers and people nearby. As a result, it’s important to identify and assess all the site risks as well as implement and maintain the control measures and safety levels in the area.
Identifying the excavation hazards
It starts with identifying the risks and hazards in the job site. Both the excavation activity itself and its after effects present danger to workers and other people within the area. For example, excavation often introduces vibration to the ground which then in turn may cause instability and falls. Hazardous gases and chemicals might also be present and depending on the concentration of the substances and the size and ventilation of the work space (i.e. confined spaces make gaseous chemicals more dangerous), the health and safety risks would be more pronounced.
Local weather conditions, soil properties (e.g. stability, presence of groundwater), the number of people involved, excavation depth and job duration can all affect workplace safety. It’s about both seeing the big picture and minding the smallest details. Whether it’s installing a new utility line or repairing the existing ones, those factors should always be considered no matter the size of the job.
To ensure and maintain site safety, it’s important to eliminate the hazards first before relying on safety devices and personal protective equipment (PPE). Safety devices and PPE (e.g. hard hats, high visibility vests) should be the final resort when it comes to protecting the workers. In many cases it’s better to make the power lines and water pipes in the job site inactive rather than making the workers wear insulating materials and other protective gear. It’s also good to pinpoint the location and depth of the utility lines so that workers can avoid them in the first place.
What about passersby, pedestrians and other people near the site (e.g. people working in restaurants and offices and those who are on their way to work)? They are also exposed to health and safety risks because the vibrations due to excavation may lead to falls, falling objects and instability. During excavation the vibrations might cause compromised tree branches to fall or for the pedestrians to lose their balance while being near the site. As a result, it’s important to keep a minimum safe distance so that other people won’t go near the area in the first place. Warning signs are still necessary but isolation and separation are still the best. For this, appropriate lights, signages and barriers can help other people (including drivers and vehicles) stay away from the site.
The risks from earthmoving machinery
Bulldozers and powerful equipment often pose a danger to the nearby people and structures because of the size, weight, movement and operation of these earthmoving tools and machinery. The weight puts some stress and load to the site surface and the vibrations might cause soil instability. On the other hand, the movement and the operation of earthmoving machinery might hit nearby objects or might require a safe working radius so that vehicles and people won’t pass by.
Although highly trained drivers can safely operate earthmoving tools and machinery, risks and hazards are still always present. For example, operating a bulldozer, backhoe or other machinery requires having the driver at an elevated height. This then restricts the visual field of the driver and thereby makes the driver fail to notice the workers and objects on the ground. The blind spots might then lead to collisions and accidents. Warning devices are great in improving safety but due to the noise and other distractions, the drivers might still fail to notice what’s on the ground. For this it’s good to establish a safe working radius in the first place so that collisions and accidents would be impossible.
Notice that the thread here is to make accidents impossible in the first place by better controlling the risks and eliminating the hazards. PPE and safety devices are the last resort because they don’t actually make the job site safer. Instead, they just protect the workers from potential hazards during worst case scenarios and emergency situations.
PPE and safety devices are still important because accidents might still happen even if we aim for a ‘zero-accident workplace.’ There are literally dozens of things that could go wrong no matter how careful we are. There’s always a level of unpredictability and uncertainty in the area especially if we’re talking about the wind, weather and other natural elements. Mistakes also happen and what we could do then is to prepare for the worst-case scenarios (e.g. by wearing PPE). Establishing a good safe distance also makes the scenario more predictable because we’ll be dealing with a lot fewer distractions.
To better manage the risks during excavation, all bases should be covered even if an event’s probability is too low. Accidents can cascade and may even start from a simple slip. Although we can’t foresee or prepare for everything, we can still greatly improve workplace safety by focusing on what we can control and by preparing for the worst-case scenarios (e.g. emergency plans, PPE, other safety devices).