Who is at fault?

I recently had an event that I would like to ask the experts on this site how they view it and how they think the outcome should be.

A machine that was designed overseas has electrical and pneumatic controls. It is clearly labeled with all the safety warning. There is also a keylock to override some of the safety devices.

Issue: Mechanic working on machine. Has to make an adjustment to a set of shears. Opens the doors but has the key switch enabled. Pushed estop and proceeds to make adjustments. A wrench falls on a sensors activating it. The stored up residual pneumatic pressure caused the shears to active causing the mechanic to require 23 stitches in his hand. Lukily did not loose anything.

Manufacturer of machine noted that during the routine in question the outputs were not locked out on the PLC. All other times they were but not this time. They send in a revised program.

The safety committee put all the blame on the mechanic. Stating the following: Mechanic did not have machine properly locked out, mechanic had safety key system enabled, mechanic did not remove all stored energy.

While I do see the companies point I dont think it fair to place all the blame on the mechanic. I beleive the mfg should also have been mentioned in the report being as they did not have the outputs locked out during that step in the process.

So in a case like this where do you draw the lines of whose at fault and what to report?

Just curious. Thanks and have a great and prosperous new year.

As a maintenance mechanic I take personal responsibility for my own safety. That means that before I work on a piece of equipment I remove all sources of energy and lock it out. I don't rely on E-Stops, safety switches or faith that nothing will go wrong. I don't care what the policy is of the company, I don't care what the standards of the machine manufacturer is, I don't care that others tell me I can work on it without lock out. I lock it out -- NO EXCEPTION.

Working on things that can or may move is why I love cribbing either wood or metal. Does not matter to me what made it move even if it was my error the cribbing has kept my arm on.

I do not think the empasis should be whose fault it is
BUT
HOW do we keep this from happening again.
Dan Bentler

The PLC outputs has nothing to do with this. They can be on or off, it doesnt matter.
Like Phillip said, ZMS is required for maintenance work.
It must be second nature for someone working on dangerous machinery.

And why was the override keyswitch enabled ? Such override keys can be used for example if you must observe what is going on with a door open, from the outside of the door. It is not intended to override the safety when someone enters or reaches into the dangerous area.

What you maybe should check up is if there are padlockable shutoffs that are easy to locate and use.
And the necessity to remove power must also be described in the user manual for the machine.
I suppose these things are OK, otherwise the committee would not have placed all responsibility on the maint.

mrtweaver said:

I recently had an event that I would like to ask the experts on this site how they view it and how they think the outcome should be.

The safety committee put all the blame on the mechanic. Stating the following: Mechanic did not have machine properly locked out, mechanic had safety key system enabled, mechanic did not remove all stored energy.

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I had to read this twice. The issue is training. All energy, pneumatic, Hydraulic, gravity, and electrical must be removed. This is the standard training procedure. If the mechanic did not understand the potential energy stored in the system, he is not liable. If the training was done and he knew the potential, he is in trouble. The training must include the stored energy of air and Hydraulic oil, and gravity. If the training videos and other material did not include this, he is less copable. Still in trouble but not fully responsible. Sorry to the the person who was injured. It was a fault of the safety department.

I agree 100% with Dan. Blaming someone does not improve safety. The more important thing is what events led up to the accident, what can we do to prevent it from happening again. Much like Air Accident Investigation, it is rarely just one thing that led to the accident. I have lots of safety training, due to different position I have held, including some years on Safety Committees.

I have seen the blame game far to many times. If we hang somebody for this, all will be well. Not very helpful though. All companies say that Safety is a priority, very few follow through.

Sometimes Maintenance Personnel have to work on powered systems for troubleshooting and adjustment. So, procedures have to be in place to allow it to be done safely.

If I am going to be working on something that can remove parts I would rather keep. It is locked out. Electrical, Air, Potential, etc. I carry a lock with me at all times.

I don't trust E-Stops, because sometimes they are just Inputs to the PLC Program. When I design a system, it has a Master Control Relay that kills power to all Outputs, and in some cases dumps the Main Air.

Having said that, I do work on running machines to troubleshoot and tune them etc. Sometimes it is the only way to see what is happening. Yet I still have all my appendages, and have had no serious injuries (e.g. No Stitches). Have I had close calls? You bet I have, and I have learned from them.

In my view, everyone involved has some responibility. Each needs to take steps to rectify thier contribution to the events that led up to the injury. The OEM to make sure all measures have been taken to insure the machine is as safe as possible. The Company to make sure there is good training and procedures. The Employee to make sure he attends and understands the training, reads the Machine manual, and understands the machine operation and possible perils.

Instead of blaming someone, lets fix it.

My 2 cents for what it is worth.

Stu....

sthompson said:

I don't trust E-Stops, because sometimes they are just Inputs to the PLC Program.

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I don't know about other parts of the world, but in Belgium it is strictly forbidden to let the PLC handle the e-stop situations unless it is a safety PLC. So, in case the e-stop is simply an input to the PLC program, any accident happening is the sole responsibility of the PLC programmer.

Kind regards,

I completely agree with Bruce.

If the mechanic was not properly trained then he should not be held accountable.

If the adjustment he was making would place him at risk, then the machine should have been locked out.

I don't like to see safety systems with overrides, but understand that they are sometimes necessary for routine adjustments and troubleshooting. But if a person must put his hands in a position that could end up causing a serious injury, then that sounds more like a maintenance task than a routine adjustment.

The new PLC program is not something I would consider a solution. It may help, but don't let that give your people a false sense of security. Proper training and a complete risk assessment are called for here. During the risk assessment, you may find that things need to be changed in the lock out tag out procedure, or perhaps even the safety circuit.

If the mechanic was properly trained and did not follow that training, then he can be blamed, but I agree with Bruce that the fault lies with the folks responsible for ensuring that (especially a new machine) proper safe working procedures were created and taught.

Paul

Seems to me to be a failure of your lock out tag out procedure. I'm surprised you allow your mechanics to work on the machine with out removing the power.

We have a machine with a very large lift table that sometimes requires maintenance and there is an LVDT under it also. Now it has cylinders to lock it in the up position just for maintenance and we also attach it to an overhead hoist to hold it and many guys get under it and work. The size and weight of this table if it were to fall on you then you are dead without question which is why i also use 6 pieces of 12 inch square tube as supports under it.

It takes a little mor time to set this up but i value my life. I tell guys here all the time "You guys may like brad and you may not like him but as for me i love him" BTW my name is brad.

PhillipD has the right attitude and the same as mine we have several pieces of equipment with several international and local safety certifications but i really don't care. I know that if i put a lock on and i have the only key and i remove all stored energy and use caution that i am as safe as i can be.

Recently here we got new locks that have a master key and there is a policy for it's use maint mgr,production mgr and one tech have to sign off and they have to call you to make sure that you are not in the planr etc. I have already seen it be misused so i have my own lock one of those vey thick ones that are pretty much bolt cutter proof and i use it where i can.It has p***ed some people off but again i don't care as it is my life on the line.

I was always trained on and still do lock out all sources of energy, drain all sources of energy, and test before I started working on any equipment. Never assume that something is going to work the way they said it will. Never trust a PLC to lock out something. I have a saying like Kid said, except mine is "If no one else loves me, I love my self".

The Plc Kid said:

Recently here we got new locks that have a master key and there is a policy for it's use maint mgr,production mgr and one tech have to sign off and they have to call you to make sure that you are not in the planr etc. I have already seen it be misused so i have my own lock one of those vey thick ones that are pretty much bolt cutter proof and i use it where i can.It has p***ed some people off but again i don't care as it is my life on the line.

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Yuck. I much prefer the bolt butter or acetylene key/cutting disc to the idea of someone else having a key to my lock...

Xactly okie that is why i purchased my own to which only i have a key and it is going to be a real operation to get it off without the key.

mrtweaver said:

Manufacturer of machine noted that during the routine in question the outputs were not locked out on the PLC. All other times they were but not this time. They send in a revised program.

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So, its a safety PLC? If not, big warning flags right here.

The mfg. should have proper safety controls in place...but ultimately the responsibility lies with the company (fines) that purchased the machine eg: procedures and proper safety controls. The bypass key should be controlled meaning that it should be given out by supervisor who could make sure proper procedures are followed. If guard is opened there should be electrical controls put in place, the bare mininum a MCR opens that would kill all output power and opens air dump vale. Furthermore this should be done with a safety relay with double redundancy and self monitoring as just a MCR relay could fail close that is why double redundancy required. As a company,operator, safety commmittes's and maintenace personnel we have a responsibility to make sure everybody goes home with 10 fingers and toes. The safety committee should have done a prestart before allowing a piece of equipment to run and determined the hazards.