Dead Man’s Switch Options for Hydro Excavation
While Hydrovac excavation is a precise and non-destructive method for excavation, mishandling or losing control of the equipment can lead to several types of damage. For instance, if hydro excavating at too high of pressures, there is a risk of damaging pipeline coatings or electrical lines. Being careful and mindful of surroundings is essential to prevent damage to utilities and equipment, or harm to others. Thus, operator training and adherence to safety procedures are crucial to mitigate the risks associated with hydrovac operation.
A kill switch (dead man’s switch) adds a layer of safety
Dead man's switches are essential safety devices in machinery and software, designed to activate or deactivate if the operator gets into a dangerous situation. Here are some common types:
Pressure-sensitive buttons
Levers
Handle grips
Sensor + software solutions
These devices play a critical role in enhancing safety but also come with limitations that must be considered in their design and implementation for every use case. Balancing safety with operational efficiency is key to their effectiveness.
Dead Man's Switches for Hydrovacs: Types, Pros, and Cons
Ball valve shut off
Pros: A ball valve is a simple and reliable mechanism that is easy to repair and maintain.
Cons: Because this valve requires manual operation, it lacks instant shut-off in emergency situations. It is the slowest and least safe option.
Pistol grip kill switch
Pros: With an ergonomic design, a pistol grip kill switch can allow for comfortable, intuitive operation and enhance operator response time in emergencies.
Cons: Because the operator must grip the switch throughout the operation of the wand, this can lead to operator fatigue, rotator cuff injuries and carpal tunnel syndrome. Operators may choose to bypass it in this situation by tying down the grip switch, effectively bypassing the safety feature. Also, the grip controls a valve in the wand so when it is used to kill the flow of water, it is simply blocking the flow at the valve in the wand. The high pressure water pump in the truck is still operating. The pressure that backs up can cause damage or failure of the water pump.
Pedal kill switch
Pros: The pedal enables hands-free operation and allows the operator to maintain a better posture and control over the lance while also reducing the fatigue associated with a pistol grip.
Cons: The pedal requires stable ground for effective use and can be a potential tripping hazard. It can be challenging to use in uneven terrain or confined spaces and operators have to constantly stop to move the pedal.
Magnet & String
Pros: With a string and magnet connecting the lance to a kill switch device, this provides a hands-free option and a fail-safe mechanism in situations where the operator is unable to reach the manual controls.
Cons: This type of safety mechanism can easily be bypassed by the operator if they feel it is getting in their way. Also, the functionality is dependent on the physical integrity of the string and magnet system, which may be susceptible to wear, damage, or environmental factors. Regular maintenance and checks to ensure reliability are required for this type of kill switch.
Motion Sensor Controls
Pros: Sensor and software based dead man’s switches provide the ability to program in use case specific detection and automated shut off. For example, if a hydrovac operator slips and the wand rapidly changes angle, the sensors will trigger a shut off faster than a human can react. If the water from the pump is turned on when the lance operator is not ready, the lance can shoot out of their hand and become very dangerous. Or, if water pressure spikes beyond a safe range, the kill switch can detect and shut off water before damage is done. Use of software and sensors (rather than just a mechanical valve) also enables this type of kill switch to shut down water flow at the pump so pressure is not building at the valve.Thus motion sensor kill switches provide enhanced safety through use case specific parameters while also protecting valuable equipment.
Cons: These devices require more training than a simple grip or valve and cost more. If they are not engineered to withstand harsh conditions, that will lead to potential issues.
A critical step to improving safety
As recent accidents have demonstrated, the integration of dead man's switches in hydro excavation equipment is critical to improving safety standards. Choosing the right type of switch depends on specific operational needs, work environments, and safety considerations. But, as regulatory bodies and hydrovac customers contemplate stricter safety mandates, adopting kill switches purpose built for hydrovac excavation can preemptively address safety concerns and reduce the likelihood of accidents.
For more information about Aarcomm’s Dig Wand Wireless Kill Switch, check out our product page.
