The Risk Management Tool Box Blog

Pyrolosis in Truck Tyres

Graham Marshall - Friday, July 19, 2013

Coming into contact with overhead power lines when driving can cause the tyres on trucks, cranes and other heavy vehicles to catch fire and explode.

Five workers have been killed by exploding tyres in Australia in recent years and many more injured as excessive heat developing in tyres has led to the unpredictable phenomenon known as pyrolysis.

Pyrolysis can occur when excess heat is applied to a tyre.

Often it is a result of electrical arcing and current flow when rubber tyred vehicles have been involved in high voltage electrical incidents.

The heat decomposes the rubber and other compounds used to manufacture the tyre, creating a ready fuel source.

The ratio of this fuel to the air used to inflate the tyres can then reach flammable or LEL (explosive) levels.

The explosive energy released during a tyre explosion can lead to serious injuries or fatalities and significant equipment damage.

Because of the amount of kinetic energy released, a danger area up to 300 metres away is typically required to be established.

Pyrolysis related explosions are unpredictable, sometimes happening immediately, sometimes up to 24 hours after the heat was applied to the tyres.

And the explosion can happen with no visible signs of a fire on the outside of the tyre before it explodes.

Besides electrical heat sources, other sources of heat that lead to pyrolysis in tyres include welding (e.g., on wheel rims), oxy/acetylene heating wheel nuts, overheating brakes and wheel motor fires.

Tyre explosions predominantly occur with split rim configurations, but can happen with all types of tyres.

Any pneumatic rubber tyred vehicle involved in an incident where an electrical fault results in discharges or arcing around or through the tyres should be considered a potential hazard.

Procedures to follow when there is a danger of a tyre explosion, such as when a rubber tyred vehicle has contacted overhead power lines include:

+ Parking the vehicle in an isolation zone, with a minimum 300 metre radius;

+ Removing everyone from the area, and not allowing anyone to re-enter the isolation zone for 24 hours; and

+ Alerting fire fighting services to the potential hazard.

It should be noted that if pneumatic tyres are filled with nitrogen instead of air, it reduces, if not eliminates the risk of pyrolyic tyre explosion.

Kinetic Energy in Crane Wire Rope

Graham Marshall - Tuesday, May 28, 2013

The safety alert (below) produced by the Marine Safety Forum highlights how the stored kinetic energy hazard within wire-rope used in slings and rigging should be understood before working on changing out such types of wire-rope.

The alert also highlights the need for: 1) Document Procedure for the task; 2)  JSA to be completed highlighting the kinetic energy hazard; and 3) No one to stand in "line of fire" when removing spooled wire-rope.

Pressurized air hose couplings

Graham Marshall - Friday, May 24, 2013

Pressurized air hose couplings which are incorrectly assembled without either a safety pin to secure the fitting or without extending the hose restraint pose a significant risk of a high velocity kinetic energy release. 

Air hose coupling failures have caused a number of serious incidents resulting in injury and fatalities.

Incorrect assembly of air hoses presents a risk not only to the person operating the equipment, but to others in the vicinity.

Equipment operators and supervisors of work activities should review their practices for the use of pneumatic tools, hoses and couplings.

It is important that members of the workforce who use this type of equipment, and those responsible for their supervision, have had the relevant training before work starts.

A JSA for use with pneumatic tools is available for purchase here.

Danger of Heating Sealed Tanks

Graham Marshall - Thursday, May 23, 2013
The dangers of applying heat ("hot work") to sealed hydraulic cylinders is highlighted in the safety alert from Work Safe in Western Australia.
The safety alert was published following the fatality of a worker who died when using an oxy-torch to cut a cylinder.
The tank exploded.

UK Pressure Safety Regulations, 2000

Graham Marshall - Sunday, March 31, 2013

In the United Kingdom, the Pressure Systems Safety Regulations (2000) deal with the safe operation of a pressure system and the Pressure Equipment Regulations 1999 deal with the design, manufacture and supply of pressure systems.

The laws for pressure systems are comprehensive because many types of pressure equipment can be hazardous.

Pressurized equipment include steam boilers and associated pipework, pressurized hot-water boilers, air compressors, air receivers and associated pipework, autoclaves, gas (eg LPG) storage tanks and chemical reaction vessels.

If not properly controlled, pressurized equipment which fails can explode and cause serious injuries and lead to fatalities.

But putting proper controls in place will minimize the chances of any unwanted pressure releases occurring.

As with all safety management, the key to good control of pressurized equipment is to assess the risk associated with the specific equipment in the workplace and to use the hierarchy of control to develop the appropriate safeguards.

The risk associated with a the failure in pressurized  equipment depends on a number of factors including:

+  The operating pressure in the system;
 
+  The type of liquid or gas under pressure and its properties;

+  The suitability of the equipment and pipework that contains the pressure;

+  The age and condition of the equipment;

+  The complexity and control of its operation;

+  The other applicable conditions (e.g., operating temperature of equipment); and

+  The expertise of the people who maintain, test and operate the pressurized equipment.

To reduce the risk associated with pressurized systems, Managers need to know (and act on) some basic precautions:

+  Ensure the system can be operated safely;

+  Be careful when repairing or modifying a pressure system;

+  Following any major repair or modification, have the whole system re-examined before start-up;

+  Ensure there is a set of operating procedures for all of the equipment in the system, including in emergencies;

+  Ensure that there is a maintenance program for the system;

+  The maintenance program should account for the age, use and the environment in which the system is used.

In addition to those controls, a written scheme of examination is required for most pressure systems:

+  This should be certified as suitable by a competent person;

+  It should address all protective devices, every pressure vessel and those parts of pipelines that could be dangerous;
 
+  The written scheme must specify the nature and frequency of examinations, and include any special measures that may be needed to prepare a system for a safe examination.

Remember, a statutory examination carried out in line with a written scheme is designed to ensure your pressure system is suitable for your intended use. It is not a substitute for regular and routine maintenance.

And finally...

+  Ensure that pressure equipment complies with the relevant regulations;

+  Before using pressure equipment, ensure that you have a written scheme of examination if one is required.

+  Make sure that inspections have been completed by a competent person, and that the results have been recorded;.

+  Always operate the equipment within the safe operating limits;

+  Provide instruction and relevant training for the workers who are going to operate the pressure equipment;

+  Ensure to have an effective maintenance plan in place, which is carried out by appropriately trained people; and

+  Make sure that any modifications are planned, recorded and do not lead to danger.

Danger from overhead falling objects

Graham Marshall - Tuesday, January 29, 2013

The danger of "working below" - in situations where items can fall from height and strike workers has again been highlighted by the prosection in the UK of Steel manufacturer Tata Steel and a specialist contractor.

A fine totalling £320,000 has been handed down for safety failings after a worker was killed by a falling metal bar in the steelworks at Redcar.

Kristian Norris from Middlesbrough was working for Vesuvius UK Limited at the time of the fatal incident on 12 April 2008.

He was hit on the head by a  metal bar that fell approximately 30 feet from overhead.

Teesside Crown Court heard today that an investigation by the UK Health and Safety Executive (UK HSE) found that adequate precautions were not in place to control the risk of falling objects.

This was a failing on the part of both Vesuvius, and Tata Steel UK Limited, which then owned Teesside Cast Products where work was being undertaken.

Tragically, both company's were aware of the safety problems but both allowed the unsafe work to continue.

Vesuvius UK Limited and Tata Steel UK Limited both pleaded guilty to breaching regulation 10(1), of the Work at Height Regulations 2005.

Vesuvius was fined £200,000 and ordered to pay costs of £24,020. Tata Steel UK Limited was fined £120,000 and ordered to pay costs of £24,020.

After sentencing, HSE Inspector Richard Bulmer, said:

"Kristian’s tragic death may have been prevented had Vesuvius UK Limited and Tata Steel UK Limited made simple and adequate provisions to protect employees working beneath work and lift platforms. The risks associated with work at height are well known, as are the necessary safeguards. Yet on this occasion the precautions taken to prevent people or objects from falling were wholly insufficient and sorely lacking."

 

UK Courts highlight the need for conveyor guarding

Graham Marshall - Sunday, January 20, 2013

The importance of appropriate guarding of moving and rotating parts on equipment has again been highlighted by the UK courts following a successful prosecution of a Deeside company.

Mainetti (UK) Ltd has been fined £60,000 and ordered to pay costs of £21,668 after a worker had her hair ripped out by a poorly guarded conveyor belt.

Kelly Nield, 25, was working on a conveyor when her scarf and hair became caught in the chain and sprocket drive of the belt as she bent over to remove accumulated clothes hangers.

She sustained serious throat injuries, lost a substantial part of her hair and fractured a finger in the incident on 11 April 2009 at Mainetti (UK) Ltd in Deeside Industrial Park.

Miss Nield needed a number of operations and was in hospital for three months.

The incident was investigated by the UK HSE which prosecuted the company for serious safety failings at Mold Crown Court.

Mainetti (UK) Ltd pleaded guilty to breaching three regulations under the Provision and Use of Work Equipment Regulations (1998) and one breach under Regulation 3 of the Management of Health at Safety at Work Regulations (1999).

Although Mainetti had fitted a guard to the conveyor, it did not fully enclose the dangerous moving parts.

And there was no emergency stop button on the conveyor.

The company's risk assessment also failed to identify the dangers of entanglement in conveyors, and the need to keep hair and loose clothing secure when near the machinery was poorly enforced.

HSE Inspector David Wynne, speaking after the hearing, said: "These horrific, life-changing injuries sustained by Ms Nield could easily have been avoided if the right safeguarding measures had been taken by Mainetti (UK) Ltd.  There are well-known risks associated with working with conveyor belts. It is vital, therefore, that the risks are fully assessed and guarding provided to prevent access to moving parts. Where appropriate, emergency stop controls should be installed in readily accessible places.  Employers must also ensure that workers are properly monitored, supervised and trained when working with this sort of equipment."

 

Common Problems With JSAs

Graham Marshall - Thursday, December 13, 2012

At the Risk Tool Box, we'd like to think that we've been at the forefront of promoting the proper use of JSA in the oil-field for the last 15-years.

We've seen just about every failing in JSA that there is to see; and we've been involved in helping numerous organizations to improve their JSA capability. 

We know that JSA is one of the most important risk management tools.  That's where we got the name for our business!

So this safety alert from APPEA shows a common failing in JSA which has been highlighted by the folks at Chevron.

The failure involves a lack of reassessment of the work following changes in the way the job was organized.

There is always a temptation amongst many workers to "get her done", and this leads to rushing-in without the necessary re-assessment when a job changes.  Revisiting the JSA is critical to maintain the currency of the control mechanisms.

Chevron needs to encourage its workforce to take the time, plan, and re-plan if things change.  To read the rest of the safety alert, see below.

 

 

 

 

Control Pinch-point Risk

Graham Marshall - Wednesday, November 07, 2012

Pinch-point incidents are common across workshops, in the field, and in office environments. 

So workers should always take care, even if an environment seems safe and hazard-free.

Typical examples of pinch-point incidents include situations where people trap their fingers in door-jams, in desk draws, in car doors, or inside equipment.

Pinch-points are produced when either two moving parts come together (e.g., when rotating gear cogs turn) or when a single moving part comes in close proximity to something solid (e.g., when a moving door slams against a door frame).

In either case, it is the kinetic energy involved with the movement potential of the object in motion that causes harm when a person gets a body part in the way!  Ouch.

Pinch-points most usually impact onto fingers or hands, but any part of the body can be impacted.

This can be particularly dangerous wherever the space between the moving parts is just sufficient to allow a larger body part to be present when the moving parts come together.

The injury resulting from contact with kinetic energy in a pinch-point can be as minor as a small cut to as severe as having your head pulled off! 

So take care around all pinch points.

The common causes of pinch-point incidents include:

●  Putting a body part in the "line of fire" of the energy source;

●  Not paying attention to hand or finger placement;

●  Wearing loose clothing, long hair or jewelry which can be caught in rotating equipment;

●  Failure to use a machine's guard mechanism;

●  Poor hand placement when lifting or moving materials during manual handling;

●  Improper use of a tool; and

●  Failing to de-energize and isolate a machine before performing some kind of inspection or maintenance task.

Because of the risk associated with pinch-points, make sure you use the following controls to stay safe:

●  Always use the Think 6, Look 6 hazard management process to identify and control pinch points in every task;

●  Use handles when opening drawers;

●  Keep fingers out of "line of fire";

●  Verify that guards are in place and used on equipment that requires guarding;

●  For some jobs, ensure you're wearing gloves (of the correct type);

●  Identify pinch-point risks and the correct controls for these on your JSA;

●  Apply lock-out, tag-out procedure for energy isolation before working on the internals of any machine; and

●  Never remove equipment safety devices.

Power Tool Safety

Graham Marshall - Sunday, April 29, 2012

This safety alert from the good folks at the Marine Safety Forum highlights the criticality of using grinders and other electric power tools which have so-called "dead-man operability".

That simply means that the grinder has an auto-shut off switch which kills the power if the tool is not being actively used.

Dead-man operability on powered tools is vital in situations where a tool could be inadvertently set down or dropped; for example if someone slips or becomes ill (e.g., heart attack).

Any auto-shut off switch on a powered tool is safety-critical equipment and it should never be purposefully over-ridden or removed.

As the example from the MSF shows, a worker using a grinder (without dead-man operability) dropped a grinding machine which continued to rotate and cut into his leg causing a 5cm gash.  Nasty!


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