OverWatch - User - Overwatch EWP Safety in Industry

OverWatch - User - Overwatch EWP Safety in Industry

Notes
This Tech Doc applies to: MEWP Operators, Site managers and supervisors, Ground staff
What is EQSS Overwatch?
The EQSS Overwatch is an Elevated Work Platform (EWP) operator monitoring and cutout type of crush protection system (sometimes called Secondary Guarding). The Overwatch system is installed on EWP machines to monitor the operator's physical movements and then cut all machine movement, should the system recognize a potentially dangerous situation. The system thereby removes the risk of the operator being crushed against the controls and the machine guard rails. The EQSS Overwatch can be fitted to all scissor lifts and vertical masts.

Why is this important?
Operators can you be crushed when operating a scissor lift? Know the risks and how to use the machine safely. Working at height requires moving the work platform near fixed structures. The operator and occupants can be in exposed positions “in the line of fire” when driving or raising the work platform.

What you need to know
You should know how the Overwatch works, how to be in correct position to operate the machine, when it is active (and not active), how to override and how to react in an emergency.

How it works
The Overwatch system is made up of a Lidar sensor and a machine control unit that monitors the Lidar and creates cutouts. The Lidar sensor sends an infra-red beam of light to measure the operator’s position. This signal occurs thousands of times every second, so it quickly identifies the operator’s movements.

What operator movements will stop the machine?
The Overwatch will activate and stop machine movement when it detects the operator moving outside of the Operator Zone or if the operator moves suddenly. 
The machine will be stopped if:
  1. the operator must move to avoid an obstacle (for example duck under piping)
  2. the operator’s movement is fast or erratic (for example looking backwards or at wheels and quickly swinging around)
  3. the operator moves away from the control box
The system compares the direction of machine movement and does not activate if the operator moves in the same direction as the machine, such as leaning forward while driving forward. Rough terrain may mean a bouncy ride, so the operator must hold on and stand firm. Fast movements indicate a potentially dangerous situation, so make sure you and the machine move slowly and smoothly. -- SMOOTH AND PRECISE --

What to do when it Activates and cuts out
To restart movement the operator must:
  1. Stand in front of the controls
  2. Release the joystick
  3. Hold the joystick and squeeze the trigger
When it is active
It is important that protection is provided for the high-risk movements – elevating the work platform and driving both forward and backwards.

The Overwatch is active for the following movements:
  1. Lift
  2. Drive forward and backward when elevated
  3. Drive forward when stowed (slab scissors and vertical masts only)
  4. Drive backward when stowed
*** It is not active when lowering the work platform - the work platform is never inhibited by the Overwatch from being lowered ***

On rough terrain “big deck” scissor lifts, it is not active when driving forward with the platform in the lowered positioned (this is identified as low exposure to crush points). When the movement is selected you will hear the command “Elevate” or “Drive”

Obstructed Sensor
The Overwatch detects if the sensor is blocked (you will hear the command “Sensor obstruction”). The operator must remove the obstruction and can wipe the sensor with a hand, glove or cloth. Neither drive nor elevate will function on the EWP until the sensor is cleared of any blocking material.

Operator and Occupants
The Overwatch monitors the operator ONLY. This reduces the risk of being crushed onto the controls or nearby guardrails. For their safety, take extra precautions if there are other occupants in the work platform.

Standing in position – the Operator Zone
The key to EWP safe use is to stand directly in front of the control box. Fatal accidents have occurred when the operator was not standing at the controls and reached behind themselves to operate the machine. The Overwatch requires the operator to stand arms length at the controls, they cannot duck down or lean over the guardrails. If you’re not in position then you will hear the command “Operator Zone”. If the operator twists their body, they are likely to move out of sensor proximity, which will cut out the machine. Try to turn your head and shoulders only, or stop and move. Keep square to the control box, by holding the left-side rail with the left hand.  

Override
A short override on the Overwatch system is available to allow for precise maneuvering of the work platform. It is limited in duration and in how often it can be used. To override the sensor, tap the joystick trigger three times. It is not possible to permanently disable the sensor.

Calibration
System calibration was completed during the installation. There is no further calibration required.

Ground Rescuer
When working at height, the best advice is to have someone available in case of an emergency. They should be competent to lower the work platform and know how to use both the lower ground controls and the emergency descent. The Overwatch allows these controls to be used. If the operator is trapped against the control box without moving for a short period, then the machine horn will sound at regular intervals (Prone operator alarm).

Revison of Key Points:
  1. Understand how the Overwatch functions and when it will be active
  2. Always stand directly in front of the controls to operate the scissor lift
  3. Understand how moving outside of the operator zone will activate the Overwatch.
  4. Know how to use the override for careful positioning of the work platform
  5. Identify the Prone Operator alarm and know how to lower the work platform in an emergency

Each Operator should:
  1. Stand square-on to the control box
  2. Hold left-side rail with left hand
  3. Operate with right hand
  4. Turn your head to look around for hazards
  5. Stop machine if needed to move body for better vision
  6. Stay in front of the control box 
Alert
Clear Operator Understanding of how to effectively use Overwatch on an EWP will greatly increase operator safety

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