Legislation and regulations have been implemented in the chemical industry as a direct result of accidents that could have been prevented if companies had followed necessary safety precautions. This includes the classification, labeling and packaging of chemicals that could potentially pose a threat. For example, in 1967, the Dangerous Substances Directive (67/548/EEC) was passed, and its orange-and-black hazardous substance symbols became instantly recognizable to anyone in the world who was handling these hazardous chemicals—anything from basic cleaning products to acids. However, this applied to Europe only, and as a result, the United Nations Globally Harmonized System of Classification and Labeling of Chemicals (GHS) was created in 1992 and standardized by 2000.
In Europe, the most important legislation introduced in recent years has been Registration, Evaluation, Authorization and Restriction of Chemicals—better known as REACH. Implemented in June 2007 by the European Union, REACH replaced 40 existing directives. There are 73 substances on the Substance of Very High Concern (SVHC) candidate list. The regulation puts greater responsibility on the industry to manage the risks of chemicals and provide safety information on the substances. However, REACH remains a work in progress.
One other way that the chemical industry is creating a safer environment is through certifications. Equipment must meet certain standards to gain certification and must be considered safe to handle known dangerous chemicals—such as acids, solvents and caustics. In the past, the CE symbol was the recognized symbol for safety. Since 1993, the CE mark has been a mandatory conformity marking for products sold in the European Economic Area. The CE mark indicates that a product conforms to essential health and safety requirements set in European Directives. In recent years, one symbol has joined CE as a trusted symbol of safety: “Ex,” better known as ATEX.
The ATEX directive is meant to protect employees and the surrounding communities from the risk of explosions. Deriving its title from the French Appareils destinés à être utilisés en ATmosphères EXplosives, ATEX consists of two European Union directives: one for the manufacturer (ATEX 95 equipment directive 94/9/EC) and one for the end user (ATEX 137 workplace directive 99/92/EC).
In July 2003, the EU made the following ATEX directives mandatory for organizations within the EU. Equipment in use before July 2003 can still be used, although a risk assessment showing that the equipment is safe is required. Equipment that is capable of causing an explosion through the equipment’s own potential sources of ignition falls under this mandate. Examples of these types of equipment are any machine, apparatus, fixed or mobile device, control component and instrumentation intended for the generation, transfer, storage, measurement and conversion of energy and/or processing of material.
Hazardous area atmospheres are classified into zones based on size, location and the likelihood of an explosion. Zones 0, 1 and 2 specify gas-vapor-mist, while zones 20, 21 and 22 specify dust. These classifications dictate that those properties be protected from sources of ignition. Zones 0 and 20 require Category 1 designation—the highest risk of an explosive atmosphere being present. Other categories are Zones 1 and 21, which fall into Category 2. Zones 2 and 22 require Category 3.
ATEX 95 directive 94/9/EC is designed to allow the free trade of ATEX-conformed equipment and protective systems within the EU by removing the need for separate testing and documentation for each member state. The regulation applies to all equipment intended for use in explosive environments, including electrical and mechanical. Equipment affixed with the “CE” marking and the “Ex” marking certify that the piece of equipment can be sold anywhere within the EU without further requirements.
Some of the most common areas in which a potentially explosive atmosphere could exist include offshore platforms, petrochemical plants and mines. Three preconditions are required for the ATEX directive to apply. First, the equipment should be intended for use in a potentially explosive environment. It should also be under normal atmospheric conditions. Finally, the equipment must have its own effective source of ignition.
The ATEX directive defines an effective ignition source as an event that—in combination with sufficient oxygen and fuel in gas, mist, vapor or dust form—can cause an explosion. Many ignition sources must be taken into account by end users, including:
Open flames and hot gases
Arcs and flashes
Mechanically generated sparks
Chemical flame irritation
Electrostatic discharge, for example, is considered one of the greatest hazards when handling dangerous chemicals. In this process, static electricity is generated by surface friction when chemicals come in contact with other materials. Typically, this occurs when the product is moved or transferred through pipes, filters, mixers and/or pumps. Static electricity may accumulate in the liquid (liquid hydrocarbons, in particular). This can lead to sparking in a flammable, vapor-air mixture.
Ignitable discharges can occur between an insulated or earthed conductive object and a charged, insulated conductive or non-conductive object. Avoiding electrostatic discharge starts with selecting the right equipment to transfer those chemicals—equipment that meets the criteria of the ATEX directive.