In this article Mike Brodie, Chemstore UK MD, outlines some of the risks associated with working with static and offers some best practice guidance.
What is static?
Static electricity is, simply put, electricity that is stuck in a system with nowhere to go. Within a typical electrical circuit, the charge is contained within a closed loop and returns to the source after carrying out a specific task, powering your kettle or lighting your office for example.
Static is different in that it can accumulate, often unnoticed, on plant, containers or even personnel. Due to lack of awareness or complacency in the workplace this build-up of energy can result in devastating, yet entirely avoidable accidents.
The accumulation of electrostatic charge is caused by barriers between the static charge and its path to ‘true earth’. For example, electrostatic charge on steel drums can be prevented from being dissipated by the presence of protective coatings, rust, debris build up and even surface layers of the stored product. Static build up on personnel can be a result of wearing the wrong footwear, or the use of insulating gloves when handling product.
Electrostatic sparking is caused by the rapid ionisation of the atmosphere between two objects at different electrical potential. When this voltage reaches a critical level, ionisation occurs in the form of a spark.
If the atmosphere across the spark is between its upper and lower flammable limits, ignition of the atmosphere will occur, resulting in fire or explosion.
The dangers of static
Possibly the most famous example of a disastrous electrostatic discharge is the Hindenburg ‘Airship’ explosion. According to a team of experts recently assigned to conclude what caused the vessel to explode on 6th May, 1937, determined the most likely cause was a build-up of electrostatic energy transferred to the airship by passing through highly charged thunderstorm clouds. The problem came about during landing, as the ground crew reached for the tie down ropes, a path was created for the charge to spark to ground as contact with the earth was made. This, in turn, ignited the Hydrogen gas used to fill the ship, resulting in the explosion that killed 36 passengers that day.
Manoa Laboratory 2016
A more recent example of disastrous electrostatic discharge includes an explosion in 2016 within the Manoa Laboratory at the University of Hawaii. Investigators noted that: –
“…serious deficiencies in the institution’s approach to laboratory safety contributed to a lapse in proper risk assessment and lack of a culture of safety that ultimately led to the accident”.
A research fellow, visiting the Hawaii Natural Energy Institute biofuels research laboratory, was transferring a mix of flammable gases into a low pressure tank when the explosion occurred. The explosion seriously injured the lab technician, causing her to lose her arm. The University suffered an estimated $1,000,000 in damage to property and faces up to $115,500 in fines.
Initial investigations put the blame on an incorrectly specified pressure gauge that was not suitable for use with flammable gases, however further studies into the event placed the blame on static discharge within the tank.
It appears the explosion could have been avoided however by carrying out a more detailed risk assessment of the process. In fact, although the experiment had been carried out 10 or 11 times previously it was noted that the investigators discovered a number of ‘near misses’ that should have caused the process to be shut down and investigated further.
For example, a ‘cracking’ sound was reported during a similar experiment on another tank but the technician was advised to simply not use that equipment again. Equally of concern is that the technician had also reported receiving static shocks when touching the pressure vessel but was told not to worry about it.
Where is static likely to occur in the workplace?
It is always essential to consider static accumulation within workplace processes, but more so when these processes involve the creation of potentially explosive atmospheres. Such activities do not have to involve large quantities of flammables liquids or dusts. A few litres of flammable liquid, under the right circumstances can create the perfect conditions for an explosion throughout a workshop or laboratory. Common activities often include the collection of waste into larger drums/IBC’s for bulk disposal, or decanting of good product from larger drums into smaller containers for transfer into the workshop or laboratory.
During both processes a release of flammable vapour is often unavoidable. A static discharge at this time can easily result in a devastating explosion or fire.
Responsibility for these activities most likely rests with the operators, however due to the absence of a visible or tangible hazard, a lack of understanding or awareness can lead to complacency or honest mistakes and an electrostatic ignition.
As an example, a calculation can be made to show the energy of an electrostatic charge typically found on a metal drum containing liquid.
Example spark energy (joules) of a steel drum containing liquid = approx. 8.0 mJ
|Liquid / Gas||Minimum Ignition Energy|
It is clear to see that there is easily enough energy in commonly found activities to ignite a flammable atmosphere (within the explosive limits) of regularly used chemicals.
There are many articles and best practice guides available in the market. In the UK, the DSEAR – Dangerous Substances and Explosive Atmospheres Regulations requires that a thorough risk assessment is carried out by a competent person.
“…Where a dangerous substance is or is liable to be present at the workplace, the employer shall make a suitable and sufficient assessment of the risks to his employees which arise from that substance. … [including] … the likelihood that ignition sources, including electrostatic discharges, will be present and become active and effective”
How Chemstore UK can help to solve the problem
Firstly, Chemstore can supply an on site assessment of your processes and facilities. If necessary, we can carry out a full DSEAR Risk Assessment for you to address any concerns you have regarding your process and to help put a plan in place for safe practices going forward.
This can then be re-enforced with operator and staff training and awareness courses to improve knowledge of the risks and associated hazards.
We can also offer a range of grounding equipment, depending on the application, to ensure operators have the right equipment to carry out the tasks on site.
Preferably, such equipment should not only monitor the presence of a connection to true earth (thus ensuring and static can safely drain away) but should also alert the operator if this state changes and the system becomes potentially dangerous.
The operator can then shut down the process until the issue can be rectified.
Static grounding requirements: What precautions should be taken when transferring flammable liquids from a metal container to a metal receiver?
When transferring liquids to/from 200L metal drums, for example – we would typically recommend using ‘pressure clamps’ capable of penetrating any surface barriers like rust, protective coatings usually present in such scenarios.
These clamps must be capable of achieving the (industrially accepted) contact resistance of 10 Ohms or less. Not only should they achieve this level of conductivity, but they should also be able to notify the operator that a good connection is ‘made’, or more importantly ‘not made’.
Please enquire here for more information on this range of active products
Although ‘active’ systems clearly offer a preferred level of risk mitigation, sites may (after careful risk assessment) elect to implement a more passive system that does not have ground status monitoring or feedback capability. In this case it is essential to understand the limitations of such a system, to ensure that a good connection has indeed been made and continues to be made during the process. The use of certified and approved Factory Mutual or ATEX equipment is essential to achieve this – which Chemstore can supply on request.
Sentence after teenage apprentice overcome by chemicals
South Tyneside Magistrates’ Court heard how, on 12 December 2017, the employee of Wheelnut Ltd, entered an area of the company’s former premises in Swalwell, Newcastle upon Tyne, known as the “acid room”. The employee entered the room to retrieve alloy wheels from one of three barrels of a chemical substance containing Dichloromethane (DCM), Methanol and Hydrofluoric Acid used in the stripping process. He was subsequently found by a colleague slumped unconscious over a barrel.
An investigation by the Health and Safety Executive (HSE) found a risk assessment for the chemical wheel stripping process was not suitable or sufficient. Appropriate control measures should have included suitable exhaust ventilation in the room as well as respiratory protective equipment (RPE) for the employees. RPE was provided but it was not maintained in an efficient or effective state. Several parts of it were damaged and the air feed to it from the compressor was not filtered correctly. The investigation found that on this occasion, and previously, the employee was not wearing the RPE when he entered the room. Employees were not provided with suitable and sufficient information, instruction, and training with regards to the risks involved with using the chemicals, particularly the risks involved with using DCM.
Wheelnut Ltd of Whickham Bank, Swalwell, Newcastle upon pleaded guilty to breaching Section 2(1) of the Health and Safety at Work etc Act 1974. The company was fined £32,000 and ordered to pay full costs of £1718.50.
Speaking after the hearing, HSE inspector Joy Craighead said: “A young worker suffered a potentially serious injury. Breathing in DCM vapour can produce narcotic effects and, at high concentrations, unconsciousness and death. In this instance, the boy made a full recovery, but it could have easily resulted in his death.”
Commenting on the sentencing, Mike Brodie, Chemstore UK Managing Director said: “A storage arrangement with suitable extraction could have prevented this incident from happening. It is easy to underestimate the dangers of gases and vapours given off by chemicals because they can be odourless and vapourless but their effects can be devastating. Thankfully the apprentice in question made a full recovery but the incident is a reminder of the importance of storing hazardous substances correctly.”
If you are unsure of your obligations in this area, contact Chemstore today for a free site assessment.
From speaking to our existing clients we repeatedly hear of uncertainty and lack of clear information and guidance on how to identify, quantify and alleviate the risks with hazardous materials in the workplace. Without accurate information we understand it makes it difficult to prepare for the risks and to be aware of what hazards are currently in your workplace.
With that in mind, we are here to enable you with the right information and tools to eliminate the risk.
The following guidance document will make it clear what steps you need to take to create a safe and compliant laboratory.
The use of hazardous and volatile materials is part of daily processes in the majority of labs in universities, research facilities and production plants worldwide. It is currently not feasible to avoid the use of hazardous materials and what is often neglected is unsafe storage of these materials. Improper storage of these materials creates a prominent risk to human life, the environment and the business itself.
Labs across all areas of industry that haven’t undergone an adequate hazardous material storage assessment exhibit common shortcomings. There is often no defined storage system which determines risks with each type of material present in the lab. Such facilities have the following unsafe storage systems and practices:
– Chemicals stored on lab worktops, benches and the floor
– Materials stored on structurally fragile shelves and above eye level.
– Not enough storage space for the hazardous material containers
– Unsafe containers used to store materials e.g. wooden cupboards
– Gas Cylinders located internally within a lab unnecessarily
– Flammables not stored in fire rated cabinets
– Excessive quantities of flammables stored internally within a lab
– Absence of inventory or stock management system for chemicals in the lab
Our team often find when meeting our clients on site that one common practice is forgotten in laboratories. There is often one designated area/cabinet or container for all hazardous materials to be stored internally. Flammables, Oxidisers, Toxic and Corrosive liquids to name a few will be stored together.
Incompatible chemicals need to be segregated according to the hazard classes of each material. This is as important as with an adequate segregation scheme adverse reactions between incompatible chemicals such as oxidisers and flammables can be avoided.
– When developing a segregation scheme for chemicals in the lab, your first point to check should be section 2 of the SDS sheets ‘ Hazards Identification ‘
– Ensure you have adequate space in your facility to allow for safe segregation and storage of each class of material.
– Some materials will have more than one hazard associated. In this case you should always identify the address the most prominent risk first.
e.g. Dimethlychlorosilane is both flammable and corrosive. In this case it would be best practice to address the flammable risk as a priority.
There is no doubt that the biggest area for concern our team always highlight with clients is the lack of awareness when storing flammable liquids internally. When carrying out a risk assessment of your laboratory and the hazardous liquids you are using and storing, you should immediately identify the flammable materials. Once you have documented an accurate list, you should then quantify in litres how much flammable materials you absolutely need to store internally in your laboratory.
It is now a legal requirement that flammables must be stored in safety storage cabinets that satisfy the requirements of EN 14470-1.
We would also like to reiterate that where possible the quantities of flammables be kept to a minimum.
Please watch the following video that will certainly portray how the negligent handling and storage of flammable liquids could have serious consequences. Risk is always present when handling and storing flammable liquids, so be the one to act and not react after it’s too late!
If you neglect the above safety procedures when handling and storing hazardous materials in your lab that you are exposing your employees, the public and the environment to untenable risks.
In order to create the safest possible environment in your laboratory the final step you need to take is to create an emergency response plan in the event an accident occurs.This plan should be carefully written and shared with all employees. All tier 1 organisations are legally required produce an emergency response plan to the local authorities as part of COMAH Regulations 2015.
Emergency response plans need to be prepared addressing all four areas above in detail including accident scenarios with the hazardous materials present in you laboratory. Once this emergency response plan has been drafted and approved by the certified body in your organisation, an open correspondence should be opened with the local emergency services and the Health & Safety authorities detailing this plan.
From gathering extensive feedback from our valued client base and extensive research carried out throughout our 23 years in business, we are constantly striving to provide our clients with the tools and knowledge to eliminate the risks associated with hazardous material storage in industry.
A key strength of Chemstore throughout its history has been anticipating and responding to the needs of our clients. Increasing the level of safety in your workplace is where our work begins. We will enable you to reduce risk, liability and downtime on your site. We will take your business beyond the legal requirements for health & safety and social responsibility in your organisation.