The Evolution of Fire Extinguishers

We take fire extinguishers a bit for granted nowadays and under health and safety laws they’re a legal requirement for the workplace, shops, schools etc basically any enclosed public space.  I bet you’ve never stopped to think about how they’ve evolved over the years.  They’ve certainly come a long way since their humble beginnings, and thankfully don’t contain the explosives they once did.  I kid you not; the first fire extinguishing machine contained gunpowder.  Fire and gunpowder – a winning combination!  The premise behind Ambrose Godfrey’s machine, which was released in 1723, was that the explosion from the gunpowder would disperse the fire suppressant over the fire.  It was only in use for a few years, which may provide some insight on its ability to do the job safely.

Since humans discovered they could create fire, it has always posed a hazard. Straw huts, wooden structures and fires didn’t particularly go together well and water was the preferred choice of extinguishing flames.  But getting the water to the fire was often an issue.  In 200BC there are records of the invention of a water pump but with absence of hoses it was an arduous task to get the water to the fire and lines of people with buckets was the only way to do this.

Ambrose Godfrey
Ambrose Godfrey

Then during the Middle Ages someone invented a ‘squirt’ which used a plunger like action to suck water into a vessel then push it out again.  These were still being used in the Great Fire of London in 1666.  Next came Godfrey and his gunpowder extinguisher!  It was in 1819 that a turn was made and Captain George William Manby introduced the first portable extinguisher.  The design featured a copper vessel that was filled with potassium carbonate and compressed air.  When released the fire was showered with the solution.  In fact some fire extinguishers today still feature potassium carbonate.

During the late 19th Century more developments were made and the soda-acid extinguisher was released. This consisted of a cylinder filled with a sodium bicarbonate and water solution.  Also inside was a vile containing sulphuric acid.  Once the two solutions combined carbon dioxide was produced which in turn expelled the water onto the fire.  All extinguishers to this point had been relatively safe to the user, however in 1912 the CTC extinguisher was invented and its contents were carbon tetrachloride. It provided an excellent solution for both liquid and electrical fires, however it proved extremely toxic in confined spaces and by the 1950’s its use had been withdrawn.

The breakthrough in fire extinguishers came with the realisation that not all fires are equal and what you use to extinguish them will play a vital role in how quickly the fire is contained and extinguished.  This knowledge has directly shaped the evolution of the myriad of fire extinguishers that we see today.  Although the choice seems confusing, it’s highly important to use the correct extinguishers for the correct type of fire to ensure you gain control and extinguish it as quickly as possible.  There are currently six classes of fire which are categorised A-F based on the property of substance that is alight:

  • Class A – solid substances such as wood, paper, plastics and textiles
  • Class B – flammable liquids
  • Class C – flammable gasses
  • Class D – burning metals
  • Class E – electrical fires
  • Class F – cooking oils and fats.

The fire extinguishers themselves can be put into six categories; however if you are looking to buy fire extinguishers you will find a great deal of options within these groups.

Water extinguishers are very effective at putting out Class A fires but should never be used for any other class as the water may make the situation worse.

Foam extinguishers can be used for Class A and B fires and they deposit a frothy mixture over the flames starving the fire of oxygen and separating the flames from the fuel.

Dry Powder extinguishers are often referred to as multi-purpose extinguishers as they can be used to tackle Class A, B, C and E fires. The powder controls the flames by acting as a coolant.

Another extinguisher that can be used for electrical fires is the CO2 extinguisher which is also effective on Class B fires.  The carbon dioxide suffocates the fire by displacing the oxygen.

The only extinguisher that can used on Class D fires is the Specialist Powder extinguisher. It is designed with a low velocity applicator that provides control over the spread of fire from combustible metals such as lithium and aluminium.

Finally, the most recent addition is the Wet Chemical extinguisher that has been introduced to address the unique character of fires started from cooking oils and fats.  Scientists developed an extinguisher that uses the chemical reaction saponification.  The wet contents of the fire extinguisher react with the oil to create a soapy substance that suffocates the flames.  Not only does it extinguish the flames but it also acts as a coolant to prevent the fire reigniting.  The development of these Class F extinguishers has been welcomed by commercial kitchens and processing plants where oil fires are high risk.

A simple risk assessment should help to determine how many extinguishers and what type are needed for your business, but educating staff is highly important to ensure that if the worse happens the right extinguisher is being used.

How Do I Do a Risk Assessment?

All businesses are required by law to carry out risk assessments in their working environment.  This can seem a bit daunting but the Health and Safety Executive (HSE) offers a great deal of help for small and medium-sized businesses, all available on-line.   If you have fewer than five employees, you are not required to write anything down. But must still undertake regular assessments.  You will find example risk assessments applying to a wide range of businesses at  These you can use as guidelines and see how other businesses have carried out their assessments.

Let’s first look more closely at what constitutes a hazard.  The term hazard covers anything that carries the potential for harm.  This would include chemicals, electricity, working at height, awkwardly placed furniture and unsecured flooring.  This is far from an exclusive list, so look at everything from a Health and Safety point of view.

A risk is best defined as the chance that anybody could be harmed by identified hazards.  You will need to assess the chance of risk, from low to high, as well as how serious the harm might be.

One important thing to keep in mind at all times is that risk assessments should be carried out regularly and particularly if conditions change within the workplace (for example, new equipment, altered premises, etc).

You don’t have to be a Health and Safety specialist to complete effective risk assessments that will help ensure the safety of your employees, customers and visitors.  The simplest thing is to divide the task into five steps.

Step One

  • What are the potential risks in your workplace?  Approach the environment with an open mind and observe and note anything that could harm people.  Think about the potential causes of accidents and illness.  You are looking here for real risks – things that are most likely to happen.  Balance these against any control measures you already have in place.

Step Two

  • Have a good think about who might suffer from potential harm and how this could occur.  This is important because different risks effect people differently.  For example, consider if any staff or customers are disabled, are more prone to slips and trips or if there are children in the environment.

Step Three

  • Once you have evaluated the risks you then need to come up with effective control measures.  Factor in the controls you have in place already and decide if further measures are needed.

Step Four

  • You need to document your risk assessment thoroughly, being sure to include measures that need to be taken to minimise the potential for harm.  Note that if you have fewer than five employees, you are not required to write anything down.

Step Five

  • Once the assessment is undertaken it should be regularly reviewed and updated.
  • Be sure to include the following in your risk assessment:
    • Each identified hazard.  For example, necessary office supplies might be stored out of easy reach of some employees.
    • Who is likely to suffer and how that might happen?  In this instance an employee might pull over a chair to reach the supplies, overbalance and fall off.
    • What controls are already in place?  Perhaps a safety step ladder is available in the store room.
    • Could you do anything more to reduce the chance of risk?  Move items needed on a regular basis to a lower level and make sure the step ladder to readily available.
    • Who is responsible for carrying out the action.
    • When the action should be completed.

As mentioned, the HSE has provided several aids which can be easily found on the internet.  Further, you will find advice on controlling risks in the work environment at

Regular comprehensive Risk Assessments are a vital tool to ensure the safety of all in the work environment.  But an assessment is not worth anything if it is not acted upon.  Both you and your staff must be diligent in following risk control measures.

Managing Psychosocial Risk in the Workplace

Managing Psychosocial Risks

Psychosocial risks within the workplace are caused by unmanageable and excessive workloads, a lack of clarity concerning work roles and the consequent conflicting demands, poor communication and poor management, particularly with regard to organisational changes.  Such factors lead to negative psychological, physical and social outcomes, one of the most significant of which is work-related stress.  This is a very real concern in the work environment, with research by the European Agency for Safety and Health at Work showing that up to five times more accidents occur when employees are working under pressure. Across Europe a staggering £98.7 billion of lost productivity results a year.

It is clear that psychosocial risks and, in particular, work-related stress are significant factors However, although 79% of companies in Europe have concerns, less than 30% have procedures in place to deal with the problem.

The first step in managing psychosocial risks is learning how to identify its presence in the workplace.  The most important thing to remember is that the problem is not a personal or individual fault, but rather a distinctly organisational issue.  A stimulating and supportive work environment is beneficial, one which makes unreasonable demands is not.  When presented with a situation that is overwhelming, the body’s reaction is stress.  This can include emotional and cognitive issues, unwelcome changes in behaviour, as well as both physical and mental ill health.

Be aware of the warning signs.  Emotional changes can include anxiety and fatigue as well as deterioration of workers’ relationships with colleagues.  If an employee is seen to be having increasing difficulty with concentration and making decisions, this is another potential alarm bell.  Watch out for significant changes in behaviour.  If an employee lapses into poor time-keeping or becomes careless or even aggressive, this may be due to work-related stress and should be immediately investigated to find the cause.  An increased amount of time off work is another sign to look out for, as both physical and mental ill health, such as depression, sleeplessness, stomach problems and back pain, can be caused by stress.

Once you have identified psychosocial risks in the work environment, you can take positive action to address the situation.

  • Make sure that, whilst being challenging and stimulating, employees’ workloads are not excessive and that they feel they have control over their tasks.  A key part of this is giving employees a chance to ‘own’ their roles by being able to make suggestions and decisions relative to their capabilities.
  • Unacceptable behaviours, such as bullying or harassment, lead to stress.  These factors may be coming from management or other workers.  Identify the source and put measures in place to stop such behaviour.  It is more than common than you might think, with almost 60% of workers across Europe stating this as a cause of stress at work.
  • A further 72% of workers have concerns regarding job security.  Do everything possible to foster job security – offer full information and communication where necessary and, once again, involve staff in plans regarding reorganisation and other significant organisational changes.
  • Workers seen to be having difficulty in successfully combining work and home commitments may feel under stress and need management support.

It is the job of management to look out for and handle work-related stress and other psychosocial risks.  Be sure that you, your managers and team leaders are aware of the warning signs and know how to handle problems once identified.  Remember that psychosocial problems at work are always an organisational issue, and management should be ever-vigilant to spot and handle any such problems.

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