We decided to draft this document to answer the growing need for transparency and information in the industrial sector. The use of flammable solvents requires highly safe equipment that complies with strict international standards such as the ATEX directive. However, regulations and safety requirements can be complex and difficult to interpret for many companies, who need to assess both legal compliance and protection for workers and the environment.
This is intended to guide customers in understanding the certifications and safety measures that are essential, clarifying the risks associated with the use of non-certified machinery and the value of third-party certifications, which are critical for accident prevention and regulatory compliance. The document also provides criteria for the safe purchase and use of distillers, promoting greater awareness of production safety and the importance of compliance to protect business integrity and the well-being of staff.
Use of solvents in industrial applications
Solvents are chemicals used in numerous industries in inks and paint production, cleaning, degreasing and chemical production. Due to their properties, which vary according to their chemical composition, the storage, use and handling of solvents can present different levels of risk, such as:
- Toxicity: prolonged exposure can cause health problems.
- Environmental impact: incorrect storage and disposal can lead to air pollution and contamination of soil and groundwater, respectively.
- Flammability and risk of explosion: many solvents are volatile and can form explosive atmospheres in the presence of oxygen.
Essential information about solvents
When dealing with solvents, it is important to know some essential physical data that affects their safety of use, particularly in terms of flammability and risk of explosion.
Flash Point (FP)
It is the lowest temperature at which a liquid releases enough vapors to form a flammable mixture with air following an ignition. Solvents with a low FP are more dangerous because they can form flammable vapors even at room temperatures.
The FP value is given in section 9 of the solvent SDS. For safety, a margin of at least 15°C below the FP shall be applied to assess flammability; can be reduced to 5°C for single-component solvents under controlled conditions.
Self-Ignition Point
It is the minimum temperature at which a mixture of combustible vapor and air can ignite without an ignition source. The self-ignition point is related to the chemical structure of the solvent and not to the boiling point or flash point, and is usually higher than the latter.
The solvent auto-ignition point is given in section 9 of the SDS. It can subside in the presence of high pressure or catalysts (such as metals found in industrial equipment): it provides an indication of the maximum temperature to which flammable mixtures can be exposed without self-ignition, but requires a large margin of safety.
Lower Explosive Limit (LEL)
It indicates the minimum concentration of solvent vapours in the air, expressed as a percentage, below which ignition cannot take place (the mixture is too "poor" in fuel).
It is essential for defining the safety conditions of the rooms and for the design of adequate ventilation systems. Below the LEL, the mixture is considered non-flammable.
Upper Explosive Limit (UEL)
It represents the maximum concentration of solvent vapors in the air, above which the mixture cannot burn (the mixture is too "rich" in fuel).
It helps to establish safe operating conditions. Above UEL, the vapor mixture is considered non-flammable, but further dilution with air can bring it back within the flammable range.
Boiling Point (BP)
The temperature at which, at atmospheric pressure, the solvent changes from a liquid to a gaseous state. It is important for distillation operations and for evaluating solvent evaporation at room temperature.
Vapour density
Indicates whether solvent vapors are heavier or lighter than air. Heavier vapors tend to accumulate at ground level, increasing the risk of fire.
Vapor pressure
Indicates the tendency of a solvent to evaporate. Solvents with high vapor pressure can form flammable mists more easily.
Risks in solvent distillation
Distillation is a physical separation technique used to purify solvents by heating, separating volatile components from less volatile ones. This process allows contaminated solvents to be recovered and reused in production cycles, reducing operating costs and environmental impact.
In addition to being heated, the waste solvent must be transferred from the storage tanks to the kettle and from the condensing system to the storage containers through which it will then be reintroduced into the processing process. During these phases, the most common risks are:
Fire
Flammable solvents have low flash points, which means they can release flammable mixture-forming vapors with air at relatively low temperatures. An ignition source, such as an electric spark, flame, or overheated surface, can start a fire. This can happen if flammable vapors come into contact with parts of the equipment that reach high temperatures.
Explosion
The presence of flammable vapours in concentrations between the lower limit (LEL) and the upper limit (UEL) can generate an explosive atmosphere. In enclosed environments or confined spaces, vapor dispersion can be limited, increasing the likelihood that an electrostatic spark or discharge will cause an explosion.
Overheating and chemical decomposition
Distillation requires the solvent to be heated. If the temperature exceeds the solvent's self-ignition point, the vapors can ignite spontaneously. Some solvents can decompose at high temperatures, releasing hazardous substances or increasing pressure within the system, which can cause explosions or equipment breakdowns.
Accumulation of electrostatic charges
Solvents with low electrical conductivity can accumulate electrostatic charges during pumping or handling. These charges can start fires if they are not properly discharged to the ground.
Mechanical and equipment breakage risk
Equipment used for distillation may be subject to wear and tear, leakage, or breakage due to pressure or overheating. This can cause liquids and vapors to leak, increasing the risk of fire or explosion.
For these reasons, it is necessary to invest in a safe and certified distiller to recover and reuse solvents in total safety, saving on operating costs and respecting environmental standards.
Installation and use of distillation units
To manage risks safely, distillation units must be built, installed and operated according to specific criteria:
- ATEX certification of all electrical equipment for use in the specific zone.
- Grounded to prevent build-up of electrostatic charges that could ignite flammable vapors.
- Adequate ventilation to reduce the concentration of hazardous vapours.
- Training staff on risks and standard operating procedures (SOPs) and emergency management.
- Installation of flammable gas detectors to monitor the concentration of vapors.
- Use of non-ferrous tools made of brass or other materials that do not produce sparks in the event of impact.
- Preventive maintenance procedures that must include periodic checks of equipment, of the condition of components, the tightness of gaskets and the integrity of safety systems.
What is ATEX?
ATEX (ATmosphères EXplosibles) is the European Directive 2014/34/EU that ensures the safe use of equipment in explosive atmospheres. This includes areas where flammable gases, vapors, or mists may be present.
Why does a distiller need to be ATEX certified?
ATEX certification ensures that the distiller has been designed and built to operate in environments where there is a significant likelihood of an explosive atmosphere forming. Certified equipment must meet high safety requirements to prevent the ignition of explosive atmospheres.
What are the benefits of installing a certified distiller?
A certified distiller is:
- Designed to avoid ignition sources, so it is intrinsically safe and mounts continuous temperature control devices that cut off the power supply in the event of overheating.
- Equipped with redundant protection systems, such as sensors and automatic shutdown devices in case of failures.
- Tested by a qualified third party, such as TÜV, to ensure it meets ATEX regulations and is suitable for use in areas with a significant risk of explosion.
The guarantees of ATEX certification
Safety in explosive environments
Certified equipment does not generate sparks or sources of excessive heat that could ignite explosive atmospheres.
Compliance with European regulations
It demonstrates that the equipment has been designed and tested to the required standards.
Reduced risk of explosions and accidents
Design, construction and maintenance follow strict criteria to minimize risks.
Need for a third party
Certification must be carried out by a body independent of the machine manufacturer, ensuring that the checks are accurate and impartial.
Support in legal liability
In the event of accidents or checks by the authorities, the presence of an ATEX certification helps to prove that the company has complied with all applicable safety regulations, thus reducing the risk of legal penalties and civil or criminal liability.
The costs of ATEX certification
The cost of a non-certified distiller is 20-50% lower than one certified by a third party. Third-party certification incurs additional costs for design, compliance testing and necessary documentation. These costs represent a significant portion of the distiller's final price. Other factors that influence the difference in cost include:
Materials and components installed
ATEX-certified distillers must use specific components (such as explosion-proof motors, protected wiring, non-sparking ventilation systems) that are more expensive than standard components.
Production and testing process
The production of a certified distiller requires more rigorous manufacturing processes, including additional quality checks and verifications, which increases production costs.
Documentation and inspection fees
In addition to the initial testing, ATEX-certified products must be documented and subjected to periodic inspections, resulting in additional expenses.
Thinking about saving money by buying a non-certified distiller involves numerous risks and disadvantages that far outweigh the immediate economic benefits
Consequences of non-compliance with ATEX regulations
Non-compliance with ATEX regulations can have serious consequences. Here are some fundamental reasons why this choice can be counterproductive and dangerous.
Lack of legal compliance
The use of non-certified equipment can result in legal penalties, fines, and obligations to suspend operations until the problem is resolved. In addition, in the event of accidents, there may be civil and criminal liability for the employer.
High risk of accidents
The damage caused by accidents with non-certified equipment can be very serious, putting the lives of workers, company infrastructures and the environment at risk.
Insurance problems
Using non-compliant equipment can also lead to higher insurance premiums, as the company is considered to be at higher risk.
Lower quality, durability and reliability
Any initial savings are quickly lost with the additional costs of repair, downtime and replacement of parts in non-certified machinery that is not built with the same quality of components or with the same safety standards, leading to frequent malfunctions and breakdowns and expensive maintenance.
Impact on the company's reputation
Any accidents caused by non-certified equipment can result in significant damage to reputation, with negative consequences for the business; in fact, customers and business partners may perceive the company as unreliable or negligent in terms of safety and sustainability.
Problems during inspections and audits
Companies are subject to periodic inspections to verify compliance with safety regulations. The use of an uncertified distiller can lead to non-compliance during inspections, resulting in the requirement to replace equipment or implement costly modifications.
Is it sufficient to install ATEX certified components for the distiller to be certified in turn?
No, it is not enough to install ATEX certified components for Zone 1 for a distiller to be automatically considered ATEX certified. Certifying the entire distiller as ATEX equipment requires more than just certified components. Various aspects must be considered to ensure that the entire machine meets the safety requirements of the regulation:
Interaction between components
Even if the individual components are certified, the way they interact with each other within the distiller could create unconsidered risks.
Specific operating conditions
Each application has unique operating conditions that must be evaluated to ensure the safety of the entire system.
Lack of comprehensive assembly testing
Certification of individual components does not guarantee that the assembled system meets ATEX requirements without proper verification.
Is it sufficient to register the technical file of the machinery with a notified third party to obtain ATEX certification?
No, registering the technical file is not sufficient to ensure compliance with ATEX regulations. Although the technical file documents the design and safety measures of the machinery, it must be accompanied by a valid ATEX certification, issued by a notified body, stating that the equipment complies with the essential safety requirements for use in potentially explosive environments.
ATEX compliance in hazardous areas
ATEX compliance is required by the European Directive 2014/34/EU, which regulates the use of equipment in areas with explosive atmospheres. ATEX zones are classified according to the probability and duration of the presence of explosive atmospheres, mainly divided into Zone 0, Zone 1 and Zone 2.
Zone 0: An area where an explosive atmosphere consisting of a mixture of air and flammable substances is present continuously, for long periods or frequently.
Example: the inside of solvent storage tanks where vapors are always present.
Zone 1: an area where an explosive atmosphere is likely during normal operation. It is present for a sufficient period of time to require special preventive measures.
Example: near the loading openings of solvent storage tanks, where vapors can escape during filling or emptying operations.
Zone 2: an area where an explosive atmosphere is not likely during normal operation and, if it does occur, is of short duration (generally less than 10 hours per year).
Example: nearby a storage area where vapors might only appear in the event of accidental leakage.
Who evaluates the classification of hazardous areas in the company?
Employer or company manager: has a legal responsibility to ensure safety in the workplace and must ensure that hazardous areas are correctly classified and marked.
Safety Officer or HSE (Health, Safety and Environment): coordinates the risk assessment and implements the necessary safety measures. It may also conduct periodic inspections to ensure that the classification of zones remains appropriate.
The correct assessment and classification of ATEX zones is essential to ensure occupational safety and prevent the risk of explosions
Under what circumstances can a manufacturer self-certify a machine?
In the ATEX environment, self-certification can only be applicable in limited circumstances, in particular for equipment intended for use in Zone 2, where the protection requirements are less stringent than in Zones 0 and 1, for which self-certification has no value.
Self-certification for Zone 2 means that the manufacturer is fully responsible for the safety of the equipment. This implies the drafting of a Declaration of Conformity and the technical file in which the safety requirements and the tests carried out are described.
In the event of an accident, the manufacturer is legally and civilly liable. Self-certification for Zone 2 may not be sufficient for insurance companies and, in some jurisdictions, may result in penalties.
Although it is legal for equipment intended for use in Zone 2, it is not a given that self-certification will be accepted by authorities or business partners, especially in areas with strict safety standards.
In many industries, customers and internal regulations require certification by a notified body even for Category 3 for Zone 2 equipment to have an additional assurance of compliance and safety.
Types of ATEX protection
Ex ia (Intrinsic Protection): limits the energy available inside the equipment, preventing ignition even in the event of failure. Suitable for Zone 0.
Ex d (Explosion-Proof Enclosure): contains a possible explosion inside the device, preventing the spread of flames. Suitable for Zones 1 and 2.
Ex p (Pressurization): Keeps the internal pressure of the equipment higher than the ambient, preventing the ingress of explosive gases. Can be used in Zones 1 and 2.
What is the relationship between the temperature class of a distiller and the auto-ignition temperature of the solvent to be recovered?
The temperature class of a certified distiller is the maximum temperature that the system can reach even in the event of a failure. ATEX temperature classes range from T1 to T6, where the maximum surface temperature is:
T1 ≤ 450°C T2 ≤ 300°C T3 ≤ 200°C T4 ≤ 135°C T5 ≤ 100°C T6 ≤ 85°C
The temperature class of the distiller must be chosen in such a way that the maximum surface temperature allowed by the equipment is lower than the self-ignition temperature of the solvent. In general, the surface temperature of the equipment should be at least 5-10°C below the solvent auto-ignition temperature to ensure a margin of safety.
Practical example: if a solvent has an self-ignition temperature of 210°C, the distiller must have a temperature class T3 or higher (T4, T5, T6), with a maximum surface temperature not exceeding 200°C.
This ensures that the equipment operates safely without risking the ignition of vapours.