What are the Types of Fire Hazards on a Construction Site?

Posted 7 years ago

Getting fire safety right in any business is crucial – especially within the construction sector. With fire and rescue teams being called to 61,103 primary fires in the year ending September 2024, it is now more important than ever to make sure you are following the correct fire safety legislation to protect your staff, clients and business.

Fire safety regulations dictate that any CDM duty holders must coordinate and co-operate on fire safety precautions with the responsible person(s) when construction work is taking place on an occupied high-rise residential building.

What is a fire hazard in construction?

A fire hazard is anything that has the potential to start or contribute to the spread of a fire. In a construction setting, this includes sources of ignition, flammable materials, and conditions that allow fires to develop rapidly. Due to the nature of construction work, sites are at a significantly higher risk of fire compared to other workplaces.

Why are construction sites particularly vulnerable?

Construction sites present a unique combination of fire risks due to:

Temporary electrical systems – Exposed wiring, faulty connections, and temporary power supplies increase the risk of electrical fires.
Flammable materials – Construction sites can contain large amounts of wood, insulation, fuel, and chemical-based products that can ignite easily.
Hot works – Activities like welding, cutting, and grinding generate sparks that can ignite nearby materials.
High activity levels – Workers using power tools, heavy machinery, and heating equipment contribute to accidental fire risks.
Poor housekeeping – Accumulated debris, sawdust, and improperly stored waste can act as fuel if a fire starts.
Changing environments – As work progresses, new hazards emerge, making ongoing fire risk management essential.

Common fire hazards on construction sites

Some of the most frequent fire hazards include:

Electrical faults – Damaged extension leads, overloaded circuits, and poorly maintained equipment can lead to short circuits and overheating.
Fuel storage – Petrol, diesel, and gas cylinders are often stored on-site, increasing the risk of explosive fires if not handled properly.
Hot work operations – Cutting torches, soldering, and welding generate extreme heat and sparks, which can ignite flammable materials.
Combustible waste –Good housekeeping is essential on a construction site. When a site is not maintained, materials such as piles of wood, cardboard, and insulation scraps can fuel a fire if not disposed of safely.
Smoking and improper disposal – Cigarettes discarded near flammable materials can easily start a fire, making designated smoking areas crucial.
Arson – Unsecured construction sites can be targeted by vandals or trespassers who deliberately start fires.

Given the number of fire hazards present, it’s essential for construction site managers to take a proactive approach to fire safety by identifying risks, implementing fire prevention measures, and ensuring all workers are trained to handle potential fire emergencies.

The fire triangle – what causes construction fires

For a fire to ignite, three elements must be present: heat (ignition source), fuel, and oxygen. This is known as the fire triangle. On a construction site, all three elements are easily found, which is why fire safety measures are so important.

To prevent fires, removing or controlling at least one element of the fire triangle is crucial. Since oxygen is naturally present in the air, fire prevention efforts typically focus on reducing ignition sources and limiting access to fuel.

But what specific fire hazards should you be looking out for?

Types of ignition sources on a construction site

Ignition sources (the “heat” in the fire triangle) are objects or activities that generate high temperatures, sparks, or flames. When these come into contact with flammable materials, the risk of fire is high.

Common Ignition Sources on Construction Sites:

Lighting – Halogen and high-intensity lights can generate enough heat to ignite nearby materials, especially if positioned too close to combustible objects.
Machinery & power tools – Equipment like welding torches, grinders, and cutting tools produce sparks that can easily ignite flammable materials. Faulty electrical tools can also overheat and cause fires.
Portable heaters – These are often used in colder months but can become a fire hazard if placed near flammable materials.
Naked flames – Blowtorches, burners, and even open flames from cooking appliances on-site pose a significant fire risk.
Smoking & lighters – Cigarettes discarded in areas with flammable debris or materials can quickly lead to a fire. Designated smoking areas should always be used.

Types of fuel sources found in construction sites

Fuel sources (the “fuel” in the fire triangle) are materials that can burn when exposed to an ignition source. Construction sites are full of these materials, so it’s important to manage these before you (or your business) get burned.

Common Fuel Sources on Construction Sites:

Rubbish & debris – Wood scraps, sawdust, and general construction waste can act as a tinderbox if not cleared regularly.
Packaging materials – Cardboard, plastic wrappings, and wooden pallets are often left lying around and can fuel a fire.
Volatile substances – Paints, thinners, adhesives, and other chemicals can be highly flammable, particularly when stored in large quantities.
Building materials – Timber, composite panels, and insulation materials can act as fuel if a fire breaks out.
Fuel-operated machinery – Diesel and petrol-powered machinery, as well as stored fuel, add another layer of risk. Spills or leaks can significantly increase fire hazards.

Fire Prevention Tip: Flammable materials and ignition sources are not friends. Keep them away from each other and ensure you dispose of waste properly.

Types of oxygen sources on a construction site

Oxygen (the “oxygen” in the fire triangle) is essential for combustion. While the natural airflow in an open construction site provides plenty of oxygen, additional sources can increase the risk of rapid fire spread.

Common oxygen sources in construction:

Natural airflow – Wind and ventilation can feed fires, especially in partially built structures.
Air conditioning & ventilation systems – These can spread flames and smoke throughout a site if a fire breaks out.
Oxidising chemicals – Some substances, such as industrial-strength bleaches and peroxides, can release oxygen and intensify a fire.

Understanding the fire triangle is key to preventing fires on construction sites. By recognising potential hazards early and taking preventative measures, construction teams can create a safer working environment and reduce the devastating impact of fires.

The legal requirements for fire safety in construction

Fire safety in construction isn’t just about best practices—it’s a legal requirement. Construction site owners, employers, and contractors have a duty to comply with UK fire safety regulations to protect workers, visitors, and the surrounding environment. Failing to meet these obligations can lead to severe consequences, including fines, legal action, or even site closures.

Here’s what you need to know about the key legal and regulatory requirements governing fire safety on construction sites.

The Regulatory Reform (Fire Safety) Order 2005

The Regulatory Reform (Fire Safety) Order 2005 (commonly referred to as the Fire Safety Order) is the main legislation governing fire safety in non-domestic premises, including construction sites. Under this order:

A ‘responsible person’ (typically the employer, site manager, or contractor) must take reasonable steps to reduce fire risks and ensure people’s safety.
A fire risk assessment must be carried out and regularly reviewed. This assessment identifies hazards, evaluates risks, and outlines measures to control them.
Emergency routes and exits must be clearly marked, well-maintained, and kept free from obstruction.
Adequate fire detection and warning systems must be in place.
Firefighting equipment (such as extinguishers and fire blankets) must be provided and properly maintained.
Workers must receive fire safety training, ensuring they understand evacuation procedures and how to respond to a fire.

Failure to comply with the Fire Safety Order can result in enforcement action from the Fire and Rescue Service, including fines and prosecution.

Fire Safety and the Construction (Design and Management) Regulations 2015 (CDM Regulations)

The CDM Regulations 2015 set out health and safety responsibilities for construction projects, including fire safety. These regulations apply to all construction work, regardless of size or duration, and impose specific duties on key stakeholders:

Duties Under the CDM Regulations

Clients (Project Owners) ensure fire risks are considered from the design stage and appoint competent contractors.
Principal Designers integrate fire safety into project planning and risk assessments.
Principal Contractors implement fire safety measures and ensure workers are aware of fire hazards and procedures.
Contractors follow fire safety protocols, report hazards, and ensure workers under their control comply with regulations.
Workers adhere to fire safety measures and report any concerns or unsafe conditions.

These regulations emphasise risk management throughout the project lifecycle, ensuring fire hazards are minimised from design to completion.

Fire safety on construction sites isn’t optional—it’s a legal requirement. By following the Regulatory Reform (Fire Safety) Order 2005 and CDM Regulations 2015, business owners, contractors, and workers can minimise risks, protect lives, and avoid costly penalties. Ensuring compliance isn’t just about following the law—it’s about creating a safe and responsible working environment for everyone on-site.

Common mistakes that increase fire risk on construction sites

Even with fire safety regulations in place, construction sites remain high-risk environments. Mistakes—whether due to oversight, negligence, or lack of training—can significantly increase the chance of a fire breaking out and spreading. Below are some of the most common errors that put construction sites and workers at risk.

Storing flammable materials too close to ignition sources

Construction sites use a wide range of flammable materials, including paints, solvents, fuels, timber, and insulation materials. When these substances are stored or handled too close to ignition sources—such as welding tools, heaters, or electrical equipment—the risk of fire increases dramatically.

You can prevent these issues by storing flammable materials in designated, well ventilated areas, and using fire resistant storage cabinets for highly flammable substances like paint thinners or fuel.

Blocked escape routes and exits

Clear and unobstructed escape routes are crucial in the event of a fire, yet one of the most common mistakes on construction sites is allowing objects to block emergency exits and pathways. In an emergency, these obstructions can lead to delays, confusion, and even fatalities.

Regularly inspecting escape routes and fire exits will help make sure that in the event of an emergency, all pathways are clear. Make sure to keep emergency signs visible and well lit so that routes are easy to navigate in a heightened situation.

Failure to inspect and maintain fire safety equipment

Fire safety equipment such as extinguishers, alarms, and emergency lighting is only effective if it is properly maintained. Unfortunately, many construction sites fail to conduct regular inspections, leading to faulty or non-functional equipment when it’s needed most.

To ensure your equipment is working and up to date with the latest systems, make sure to plan out regular inspections on all fire safety equipment, and replace any damaged equipment immediately.

Fire hazards on construction sites can often be traced back to avoidable mistakes. By implementing proper storage, clear escape routes, good housekeeping, regular fire drills, and equipment maintenance, construction managers can significantly reduce the risk of fire. Fire safety isn’t just about compliance—it’s about protecting lives and ensuring the long-term safety of every worker on-site.

What’s the appropriate equipment to have to put out fires on construction sites?

Having the right fire-fighting equipment on a construction site is essential for quickly containing small fires before they spread and cause serious damage. Due to the variety of fire hazards, different types of equipment are needed to tackle different fire sources. Here are some essential firefighting tools every construction site should have:

Types of fire extinguishers needed on construction sites

Not all fires are the same, which means a one-size-fits-all approach to fire extinguishers won’t work. Construction sites should have the following fire extinguisher types, each suited to different fire risks:

Water Extinguishers – Best for Class A fires (wood, paper, textiles, and general combustible materials). Not suitable for electrical or flammable liquid fires.
Foam Extinguishers – Effective on Class A and Class B fires (flammable liquids like paints, oils, and solvents).
CO₂ (Carbon Dioxide) Extinguishers – Designed for electrical fires, commonly found near power tools, machinery, and site offices.
Dry Powder Extinguishers – Versatile and can tackle Class A, B, and C fires, including flammable gases (propane, butane) often found on construction sites. However, they create a lot of dust and can reduce visibility, making them less ideal for enclosed spaces.
Wet Chemical Extinguishers – Primarily used for cooking fires involving grease and oil, so they are less commonly needed on a construction site unless there is an on-site kitchen or catering area.

Fire blankets and their uses

Fire blankets are simple but effective for smothering small fires, particularly those involving clothing, welding sparks, or small flammable liquid fires. On a construction site, they can be useful for:

Putting out fires on a person’s clothing, preventing severe burns.
Covering small fuel or liquid fires, cutting off the oxygen supply.
Extinguishing welding sparks before they ignite nearby materials.

Fire suppression systems

For larger or high-risk construction projects, fire suppression systems can provide an extra layer of protection. These systems are designed to detect and suppress fires automatically, minimising the risk of escalation. Some key systems include:

Sprinkler systems – Effective in fixed-site construction offices or high-risk storage areas, these systems activate when heat is detected and release water to douse flames.
Misting systems – Similar to sprinklers but release a fine mist rather than large amounts of water, reducing water damage while effectively suppressing flames.
Automatic fire suppression units – Often used in high-risk areas such as fuel storage locations, these systems can use foam or gas-based suppression to contain fires instantly.

Remember, having the right fire-fighting equipment is only effective if it’s in good working condition. Regular inspections and maintenance ensure that everything is ready to be used in an emergency.

Construction sites are high-risk environments where fire hazards are always present. By ensuring that the correct extinguishers, fire blankets, and suppression systems are available, and keeping them well-maintained, business owners and site managers can prevent small fires from turning into major incidents. Fire safety is not just about meeting regulations but about protecting workers, equipment, and the project itself.

Carry out a construction fire risk assessment

It’s a legal obligation under the FSO 2005 that a “responsible person” must carry out a risk assessment on a construction site (or any work premises, as a matter of fact).

There are certain elements you must assess when it comes to a fire risk assessment. The HSE states that these are the five steps in carrying out a fire risk assessment:

Identify hazards – consider how a fire could start and what could burn;
Identify those at risk – employees, contractors, visitors, and anyone who is vulnerable;
Evaluation and action – consider the hazards and people identified in 1 and 2 and act to remove and reduce risk to protect people and premises;
Record, plan, and train – keep a record of the risks and action taken. Make a clear plan for fire safety and ensure that people understand what they need to do in the event of a fire; and
Review – your assessment should be regularly reviewed to make sure that it takes account of any changes on site

A well-developed fire safety plan is only effective if workers know how to follow it. This is why fire awareness training is essential. Training ensures that every worker understands fire risks, evacuation procedures, and how to respond in an emergency. Investing in fire safety training courses can reduce the risk of incidents, ensure legal compliance, and ultimately save lives.

Fire Awareness Training In Construction

Here at iHasco, we offer an online Fire Awareness Training course for construction to help you identify the possible fire hazards in your workplace before any accidents occur. It also covers topics like which fire extinguisher to use and what fire signage is needed around the site.

Additionally, we offer online Fire Awareness Training courses for other industries:

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