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Working to standards and directives

We understand how important it is to ensure your systems comply with appropriate legislation and guidelines and so we pride ourselves in keeping abreast of the latest developments.

There are a number of different pieces of legislation that are relevant to dust control and we will help you identify what is relevant based on what you are processing and ensure our systems are compliant.

COSHH Regulations – Control of Substances Hazardous to Health Regulations 2002

COSHH applies to a wide range of substances which have the potential to cause harm to health if they are ingested, inhaled, or are absorbed by, or come into contact with, the skin, or other body membranes. Hazardous substances can occur in many forms, including solids, liquids, vapours, gases and fumes. A substance hazardous to health need not be just a chemical compound, it can also include mixtures of compounds, micro-organisms or natural materials, such as flour, stone or wood dust.

Dust of any kind can also become a substance hazardous to health under COSHH when it is present at certain concentrations in the air.

In simple terms, employers must assess the risks and put measures in place to prevent or control exposure.

Impact can help to control exposure at source with the design and installation of local exhaust ventilation systems.

Once installed we can then provide regular thorough examination and testing as required by the Regulations to ensure that the controls remains effective.


HSG 258 – Controlling Airborne Contaminants at work

This guidance focuses on the design of new local exhaust ventilation (LEV) equipment. It also describes the principles of deciding on, designing, commissioning and testing effective LEV. This guidance is written for employers who use or intend to use LEV. The guidance will also help suppliers of LEV, managers, trade union and employee safety representatives.

All of these groups need to work together to provide, maintain and use effective LEV and to reduce exposure from the inhalation of hazardous substances. The guidance contains information about the roles and legal responsibilities of employers and suppliers; competence; principles of good design practice for effective LEV hoods and their classification; ducts, air movers; air cleaners; and system documentation – with checking and maintenance schedules and the marking of defective equipment. It also includes guidance on the specification of LEV; commissioning; zone marking; the user manual and logbook; testing and hood labels.

Impact have years of experience in both designing and installing and testing LEV systems.  Our engineers are also trained to BOHS P601 or P602 (the training standard approved by the British Occupational Hygiene Society). 


EH40 Workplace Exposure Limits

The HSE has established WELs for a number of substances hazardous to health. These are intended to prevent excessive exposure to specified hazardous substances by containing exposure below a set limit. A WEL is the maximum concentration of an airborne substance averaged over a reference period to which employees may be exposed by inhalation.

Impact can help employers to correctly apply the principles of good practice for the control of substances hazardous to health, ensuring that exposure is below relevant WEL levels.


The Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR) place duties on employers to eliminate or control the risks from explosive atmospheres in the workplace.

In DSEAR, an explosive atmosphere is defined as a mixture of dangerous substances with air, under atmospheric conditions, in the form of gases, vapours, mist or dust in which, after ignition has occurred, combustion spreads to the entire unburned mixture.

Many workplaces may contain, or have activities that produce, explosive or potentially explosive atmospheres. Examples include places where work activities create or release flammable gases or vapours, such as vehicle paint spraying, or in workplaces handling fine organic dusts such as grain flour or wood.

DSEAR requires employers to eliminate or control the risks from dangerous substances. In addition to the general requirements, the Regulations place the following specific duties on employers with workplaces where explosive atmospheres may occur.

Employers must classify areas where hazardous explosive atmospheres may occur into zones. The classification given to a particular zone, and its size and location, depends on the likelihood of an explosive atmosphere occurring and its persistence if it does. Schedule 2 of DSEAR contains descriptions of the various classifications of zones for gases and vapours and for dusts.

Areas classified into zones must be protected from sources of ignition. Equipment and protective systems intended to be used in zoned areas should be selected to meet the requirements of the Equipment and Protective Systems Intended for Use in Potentially Explosive Atmospheres Regulations 1996. Equipment already in use before July 2003 can continue to be used indefinitely provided a risk assessment shows it is safe to do so.

Equipment and protective systems intended for use in explosive atmospheres

The aim of Directive 94/9/EC is to allow the free trade of ‘ATEX’ equipment and protective systems within the EU by removing the need for separate testing and documentation for each Member State.

Manufacturers and suppliers (or importers, if the manufacturers are outside the EU) must ensure that their products meet essential health and safety requirements and undergo appropriate conformity procedures. This usually involves testing and certification by a ‘third-party’ certification body (known as a Notified Body) but manufacturers/suppliers can ‘self-certify’ equipment intended to be used in less hazardous explosive atmospheres. Once certified, the equipment is marked by the ‘EX’ symbol to identify it as such.

Certification ensures that the equipment or protective system is fit for its intended purpose and that adequate information is supplied with it to ensure that it can be used safely.

National Fire Protection Association (NFPA)

Due to a growing number of catastrophic fires and explosions caused by combustible dust in the last decade, OSHA has recognized combustible dust as a hazard. The presence of dust in a factory is now at the top of the list of items to inspect during an audit. The Combustible Dust National Emphasis Program issued by OSHA in 2008 instructs inspectors on how to identify combustible dust hazards.

Incident history and statistics clearly indicate that secondary dust explosions, caused by inadequate housekeeping and excessive dust accumulations, have caused much of the damage and casualties experienced in major industrial dust explosions.

The NFPA have developed many standards to control the risks associated with dust explosions within various industries.

Summary of NFPA standards governing the management of combustible dust hazards.




NFPA 652

Standard on the Fundamentals of Combustible Dust

NFPA 654

Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids


Guide for Venting of Deflagrations


Standard on Explosion Prevention Systems

NFPA 499

Recommended Practice for the Classification of Combustible Dusts and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas


Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities

NFPA 484

Standard for Combustible Metals

NFPA 655

Standard for Prevention of Sulfur Fires and Explosions

NFPA 664

Standard for the Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities


In our experience within the manufacturing industry, the most relevant standard is NFPA 654.  The goal of the NFPA 654 standard is to provide safety measures to prevent and mitigate fires and explosions in facilities that handle combustible particulate solids. This standard applies to all phases of the manufacturing, processing, blending, conveying, repackaging, and handling of combustible particulate solids or hybrid mixtures, regardless of concentration or particle size, where the materials present a fire or explosion hazard. The owners or operators of affected facilities are responsible for implementing the requirements.