Flammable materials are substances that can ignite easily and burn rapidly. They can be common materials that are at most work sites in gas, liquid and solid forms. Proper flammable material storage needs to be followed to avoid an accident in the workplace. Some flammable materials which pose a risk include:
Gases — Natural gas, propane, butane, methane, acetylene, carbon monoxide, hydrogen sulphide. Flammable gases usually have with a lower explosive limit of less than 13% in the air or have a flammable range in air of at least 12%. For example, butane is a flammable gas because its lower explosive limit in the air is 20%. Carbon monoxide has a lower explosive limit of 13% and an upper explosive limit of 74% in air, it is flammable over a range of 61%.
Liquids — Many solvents such as acetone, alcohols and toluene, paints and paint thinners, adhesives, degreasers, cleaners, waxes and polishes. Flammable liquids have a flashpoint below 37.8⁰C (100⁰ F).
Solids — Some types of coal, pyrophoric metals (metals that burn in contact with air or water, such as sodium and potassium) solid wastes that are soaked with flammable liquids (rags, paper, spill clean-up products) and matches.
To read more about our best-in-class flammable materials storage, read up on our Fireavault range here.
For a fire to occur, three elements must come together at the same time and in the right proportions, fuel, heat (ignition source) and oxygen. Remove any of the elements and the fire will go out.
The “fire triangle” is commonly used as a model to understand how a fire starts and how it can be prevented.
Fuel — Fuels are flammable or combustible materials and can be gases, liquids or solids.
Heat — These are ignition sources and include an open flame, lit cigarette and sparks (such as from electrical current and static electricity shorts). A chemical reaction that creates heat can also ignite a fuel and oxygen mixture.
Oxygen — The most common source of oxygen is air, but oxygen can also come from chemicals called oxidizers. Examples of common oxidizers are some types of acids and chemicals such as chlorine, chlorine dioxide, potassium permanganate and potassium chlorate.
The spread of fire is also dependant on a fourth factor, the chemical chain reactions that occur after the fire is started. Fire prevention consists of making sure that the three legs of the fire triangle never meet. It is important to note that a fire will not always start even when the legs of the triangle meet unless all three elements are present in the right amounts. For example, vapours from a flammable liquid must be mixed with a certain amount of air and exposed to the right amount of heat to ignite and burn. Once vapours from a flammable liquid have ignited, the flames may “flash-back”. This means the flames travel back, through the vapour air mixture, to the container or source of the flammable liquid. This can create an explosion. Most flammable liquids produce vapours that are heavier than air. Some flammable gases are also heavier than air. These gases and vapours can spread a considerable distance along the ground or floor and be ignited by a distant spark or flame or source of heat. Certain chemicals such as organic peroxides (e.g. benzoyl peroxide) contain both fuel and oxygen.
The employer must develop work procedures for the use and storage of flammable materials and ensure workers are trained on these procedures. Because of the potential fire hazard, the employer will also need to have additional procedures in place to deal with fires and spills.
Work procedures should address:
In general, flammable materials must not be stored near exits, electrical equipment or heating equipment. They should always be stored in a separate, well-ventilated storage area, away from potential sources of ignition. If the material is removed from its original container, it must be placed into a container that is appropriate for flammable materials.
When flammable liquids are transferred from their original container (one they were purchased in), or from bulk storage such as a drum or tank, the proper type of portable container must be used. Containers that are approved for the use and storage of “portable quantities” are usually made of metal or plastic, are vapour-proof and have:
Portable containers must be properly labelled. The labelling should include the following information:
When individual containers of flammable liquids are not in use and are stored inside a building, they should be stored in a storage cabinet. The European Standard EN 14470-1 was implemented in April 2004 and has since been published as a national standard in many European countries as the Netherlands, France, Ireland, Spain, UK, Italy etc.
Since the 1st of January 2005, the former German Standard DIN 12925-1 can no longer be taken into consideration for testing Safety Storage Cabinets.
Test and construction requirements, compared to the DIN 12925-1, have become stricter and in some details stated more precisely. The following points describe the basics and main safety, test and construction requirements.
The range of applications
– The standard specifies the performance required of the design and fire resistance of safety storage cabinets used for storing flammable liquids in working areas.
The principal safety requirements
– Minimisation of the fire risk associated with the storage of flammable materials.
– Protection of the contents of the cabinet in the event of a fire for a known (and tested) period of time.
– Minimisation of the fumes released to the working environment.
– Retention of any possible leakage within the cabinet.
– Provision of enough time, in the event of a fire, for personnel to leave the room,
and sufficient time for fire service personnel to enter the building before the
stored materials turn a small fire into an uncontrollable blaze.
– In the event of a fire the cabinet must ensure that, over a period of time defined by the manufacturer (but in any event at least 15 minutes), its contents do not present an additional risk that the fire will spread.
– The cabinet doors must close entirely, starting from any position (closing time max. 20 seconds).
– Immobilising equipment fitted must release the locked doors at a temperature of 50 (-10) °C.
– Avoiding the risk of injury: the closing force of the doors must not exceed 100 N.
– One-handed operation must be possible, and the doors must close entirely even if open and locked.
Side and rear walls
– The side and rear walls of the cabinet must have the same thickness and comparable structures.
Air inlet and outlet openings
– The cabinets must have openings for air inlet and outlet (for connection of the cabinet to an exhaust system).
– The ventilation openings must close automatically at a temperature of 70 °C.
Storage locations (shelves or drawers)
– Storage surfaces must be able to support the loading specified by the manufacturer throughout the test in the furnace. Design evidence of the load-carrying capacity of shelves and drawers in the event of fire based on EN 1365 (fire resistance tests for self-supporting components).
Spill containment sump
– The spill containment sump must retain its ability to function after the fire resistance test. This is to be checked visually by filling the spill containment sump with water
– Must be investigated by tests on a design sample.
– The fire-resistant cabinet is exposed to flames in a suitable furnace.
– The doors, walls and ceiling of the cabinet being tested must be exposed to the same heating conditions.
– Cabinets must be tested as free-standing single cabinets. The example being tested must be positioned with its rear wall at least 100 mm from the furnace wall.
– The flame exposure is carried out under the standard temperature curve of BS EN 1363-1.
– The temperature rise is measured inside the cabinet.
– The cabinet must then be classed as type 15, 30, 60 or 90, according to the time that has elapsed before the temperature rose by 180K.
At some work sites, there are many different types of flammable materials or large volumes of particular materials used. At these sites, flammable materials may be stored in large containers (drums or tanks) or there may be a specific flammable material storage room. The specific requirements for above ground storage tanks and storage rooms is HSg51.
|Quantity Stored (L)
|Up to 1,000
|1,000 to 100,000
To prevent fires, flammable materials must be properly managed in the workplace. There are three main ways to prevent fires:
Limit the amounts of flammable and combustible materials
Provide proper ventilation to ensure flammable vapours do not accumulate
Control ignition sources
Static electricity is an electric charge that cannot move. It is created when two objects or materials that are in contact with each other are separated. While the objects are in contact, the surface electricity charges try to balance each other. When the objects are separated, they are left with either an excess or shortage of electrons, causing them both to become electrically charged. If these charges do not have a path to the ground, they are unable to move and becomes “static”. If static electricity is not quickly removed, the charge will build up. Eventually, it will develop enough energy to jump as a spark to some nearby less highly charged object. In an explosive or flammable atmosphere, the spark can set off an explosion or fire. The danger is greatest when flammable liquids are being poured or transferred.
Static electricity can be produced by:
Static electricity can be controlled by:
Bonding and grounding are techniques that are used to prevent sparks (a source of ignition) from being created when liquids are transferred between containers. Bonding is when there is an electrical connection between two or more conductive containers. Bonding ensures that the containers have the same electrical charge. Without a difference in charge, a spark cannot be created that jumps from one container to another. Bonding does not eliminate the static charge which is why it is used in combination with grounding. A container is grounded when there is an electrical connection between the container and the earth. Grounding quickly drains the static charge away.
If you have any questions about our Firevault range or flameproof cabinets, get in touch today by calling, emailing or using the Live Chat feature on the bottom left corner of your screen.
While there is widespread appreciation of the need to store flammable substances safely warehouse fires are still a regular occurrence and incorrect storage of flammable substances is often found to play a part in these incidences.
When such a fire occurs it is not necessarily the case that there is a complete disregard for safety, but there are some common mistakes that we witness during site visits that put premises and people at increased risk.
One example is the assumption that storing drums containing flammable substances in an off-the-shelf chemical store means they are safe when this may well not be the case. Often standard stores don’t offer thermal protection which means once the weather heats up the products inside the store do too at which point they can start to give off a flammable vapour and become hazardous.
This is a very simple example but the reality is that storing flammable substances is rarely straight forward with every site having a bespoke set of factors that need to be taken into consideration. It’s therefore useful to consult a hazardous storage expert to ensure that you find the most appropriate solution for your needs but this doesn’t mean you can’t do some ground work first to help you build a picture of your requirements.
The most useful reference tool you have when looking at how to store a flammable substance safely is the product’s Safety Data Sheet (SDS) which will either be provided with the product or be available online – if in doubt contact the manufacturer/supplier. Safety Data Sheets can seem overwhelming at first glance but once you know what you are looking for they are actually quite easy to navigate and the following steps can help.
1. Identify the chemical. First of all, you need to know what you’re dealing with so refer to sections 1& 2 of the Safety Data Sheets to identify the substances you want to store and their associated hazards. Once you have this information use section 9 of the Safety Data Sheet to identify the flashpoint of the substance – make sure you are clear about the difference between the flashpoint and the auto-ignition temperature as it is a common mistake to get these confused. A misconception is that the flashpoint of a liquid is the temperature at which it auto ignites – this is incorrect – the temperature at which it auto ignites is called the autoignition temperature. The flashpoint is the temperature at which the liquid gives off flammable vapour. It is not the liquid but the vapour that ignites, so storing a product below this temperature means that no flammable vapour is created. Controlling the temperature also has another benefit that the flammable or hazardous material may work better in process or application when stored at a certain temperature, this temperature can be found in Section 7 of the Safety Data Sheet.
2. Consider compatibility. If you are storing more than one substance, consider whether they are compatible as certain chemicals need to be segregated within a storage facility. Refer to Section 10 of the Safety Data Sheet to identify incompatible materials.
3. Define the application. Consider how you are using the substances as this will affect the level of risk. Bulk storage of unopened items in sealed containers poses a much lower risk of giving off a flammable vapour than storing products in use where a seal has been broken and lids may not be replaced properly. That said, manufactured sealed containers can cause an issue when stored above the flashpoint and the container is trying to release the vapour because the vapour has nowhere to go which will create pressurised containers that eventually burst or go bang. Remember that you need to think about what will happen to your store if a fire breaks out elsewhere in your facility as well as the risk of a fire breaking out within the store itself.
4. Combat the risks. Think about how you can combat these risks using a hierarchy of hazard controls approach. First, consider whether you could use an alternative substance that poses less of a risk. If this isn’t possible think about what you can do to reduce the risks. Firstly think about thermal protection and temperature control – ensuring a product is stored at the correct temperature as per the Safety Data Sheet will help to prevent flammable vapours from occurring – you also need a way of monitoring this temperature – preferably via a remote system that will alert you of any critical changes in temperature. Next consider whether you need an extraction systems to remove vapour in the event that it does get released, once again this needs to include VOC/gas detection monitoring so you receive an alert if there is a rise in vapour so you can address the situation. The next step is to think about fire detection systems to raise the alarm if you have a fire – a double knock system can reduce false alarms so this might be worth considering. Your unit also needs to include the most appropriate fire suppression media which varies depending on the hazard and will be highlighted in Section 5 of the Safety Data Sheet. Frustratingly sometimes the information within these sections can seem contradictory, for example within the Safety Data Sheet for acetone Section 5 recommends using water sprays but not to use water jets – this is why consulting an expert in hazardous storage is advisable. There is also currently some confusing and contradictory information surrounding the most appropriate media for extinguishing lithium-ion battery fires. This reiterates why it is important to consult a hazardous storage expert with experience in these areas.
5. Have a fire response plan. Anyone storing flammable substances needs to be able to instantly know what’s in their building and what you’ve done to protect your site and the surrounding neighbourhood so ensure you have a detailed inventory that can be accessed quickly in the event of an incident. For example Chemstore’s cloud-based hazardous material management software system, Chempli, which can be specified with a unit, includes a QR code that can be featured outside a building or at a security gate enabling the user to instantly access the relevant information in the event of an incident.
This is a very basic guide to some of the factors that need to be taken into account when planning the storage of flammable substances but hopefully it provides enough information to give you an understanding of the needs on your site. If you are in any doubt about your current storage arrangements, or you are in the process if specifying a new system, contact Chemstore Engineering today for a free site survey.
Walk In Fire Rated Stores Stores
The FireVault storage module provides the highest level of safety instantly for the secure storage of all flammable materials. All areas of industry currently employ flammables in their processes from petroleum products to industrial chemicals.
Manufactured to the highest standards utilising only those fireproofing materials, which have been tested to BS 476, part 22, FireVault Stores comply with all relevant Health & Safety Regulations, Insurance requirements and environmental standards such as IS310, ISO 14001, EMAS and IPC licensing.
Standard features include, full width spillage collection sumps, up to 5 hour fire rated composite wall panels, insulated self-closing doors, intumescent ventilation panels, fixed shelving, anti-static grounding connections, fully welded, leak tested bunds, galvanized grid mesh floors. A range of optional extras are also available for the Firevault units including ex-rated electrical fittings.
All Firevault units are delivered to site fully assembled and ready for immediate use. No special site works are required and at any future time, they can easily be relocated by forklift truck or crane, thereby offering excellent flexibility.
The most common Firevaults are the Walk In Stores used for small container storage (25L cans, Winchesters etc) and feature:
Mat Mitchell spoke to us after receiving a bespoke Firevault – fire rated drum & ibc store on site in the UK .
“After consulting with various suppliers, Chemstore was the only company who could provide us with the required solution” Mat Mitchell Technology Supplies Ltd. –
Fire Rated Stores for: Drums, IBC’s & pallets of flammable materials.
FireVault units are fully modular and can be easily relocated by forkturck or Hi-AB Crane
All Firevault units are delivered to site fully assembled and ready for immediate use with no site work required.
Firevault Multi Pallet Stores feature:
See table below for our range of sizes below
Organic Peroxide Storage – Stainless Steel
Typically, chemical stores would be fabricated from mild steel which is then over-painted with a 2-part or 3-part industrial paint system. Standard units would also have exposed galvanized grid decking onto which the pallets would rest – these are unpainted and therefore expose the mild steel to the chemicals stored – in this case Organic Peroxide. Read on for our solution to your organic peroxide storage needs.
When designing an organic peroxide store a Grade 316 stainless steel finish is required, in all locations that could come into contact with the Peroxide. This includes the storage areas, the spillage retention bunds and the fire water retention tank.
The relevant HSE Guidance reference is called: –
CS21 – The Storage and Handling of Organic Peroxides. – Download it here
This is written, specifically to cover the
“… handling and storage of organic peroxides at customer or user sites.”
It clearly details the hazards associated with exposing such chemicals to mild/carbon steel: –
“… commercially available organic peroxides are capable of self heating and runaway decomposition. Initiation is by heating or contamination with, for example, transition metal compounds (particularly those of vanadium, chromium, manganese, iron and cobalt) amines, strong acids and alkalis.”
Furthermore, para 28, when discussing the handling of organic peroxides, states that: –
“… All containers and equipment which come into contact with peroxides must be compatible. Suitable materials include glass, porcelain, polyethylene and 316 grade stainless steel.”