EN IEC 60721 Classification of Environmental Conditions

The “EN IEC 60721 Classification of environmental conditions” standard, which is based on a European standard and subsequently published by the International Electrotechnical Commission (IEC), consists of the following sub-sections published under the same title:

• The standard “EN IEC 60721-1 Part 1: Environmental parameters and their severity” lists the environmental parameters and their limited severity within the range of conditions encountered by electrotechnical products during transport, storage, installation and use. This standard defines the types (climatic, mechanical, chemical) of environmental parameters and the principles of their classification.
• The standard “EN IEC 60721-2-1 Part 2-1: Environmental conditions occurring in nature - Temperature and humidity” covers the classification of outdoor climates in terms of temperature and humidity. This standard is intended to be used as part of the background material in selecting appropriate temperature and humidity intensities for product testing and applications.

The climates cover all regions of the world except Central Antarctica and high altitudes (above 5.000 m). This standard can be used as background material when determining climatic environmental classifications for product applications.

This standard defines a limited number of outdoor climate classifications in terms of temperature and humidity, representing the most common conditions encountered during the transportation, storage, installation, and use of products.

• The standard “EN IEC 60721-2-2 Part 2-2: Naturally occurring environmental conditions - Precipitation and wind” describes the basic properties, characterization quantities, and classification of environmental conditions related to precipitation and wind for electrotechnical products. This standard is intended to serve as background material for selecting appropriate parameter intensities related to precipitation and wind for product applications. The values ​​given in the IEC 60721-1 standard should be applied when selecting the parameter intensities related to precipitation and wind for product applications.
• The standard “EN IEC 60721-2-3 Part 2-3: Environmental conditions occurring in nature - Air pressure” presents a selection of different air pressure values ​​encountered in nature. This standard is intended to be used as a fundamental resource in selecting appropriate air pressure intensities for product applications where exposure during storage, transport, and use is possible.
• The standard “EN IEC 60721-2-4 Part 2-4: Naturally occurring environmental conditions - Solar radiation and temperature” provides a broad classification of types of solar radiation fields. This standard is intended to be used as part of the background material for selecting appropriate solar radiation intensities for product applications. All geographical area types are covered, except for altitudes above 5.000 m. This standard also serves to define the limits of solar radiation intensities to which products may be exposed during transport, storage, and use.
• The standard “EN IEC 60721-2-5 Part 2-5: Naturally occurring environmental conditions - Dust, sand, salt mist” provides information on the formation and properties of dust, sand, and salt mist. This standard describes the effects of these environmental factors to which products may be exposed during storage, transport, and use. The effects of dust, sand, and salt mist can be increased by precipitation and wind.
• The standard “EN IEC 60721-2-6 Part 2-6: Naturally Occurring Environmental Conditions - Earthquake Vibration and Shock” addresses naturally occurring environmental conditions related to earthquake vibrations and shocks. The aim of this standard is to define some fundamental characteristics and quantities for characterizing earthquakes as background material for the intensities to which products may be subjected during storage and use. The accelerations given are only for ground surface conditions. References to conditions related to structures are made, but are limited to general condition descriptions.
• The standard “EN IEC 60721-2-7 Part 2-7: Naturally occurring environmental conditions - Fauna and flora” addresses the occurrence of fauna and flora and their fundamental effects on electrotechnical products. Exposure to and damage from fauna and flora can occur at almost any point in a product's life cycle. Furthermore, there are numerous attack agents with varying effects.

This standard addresses the occurrence of fauna and flora and the damage they cause in all locations where a product may be stored, transported, or used. Generally, fauna can be found in both natural environments in open-air spaces and artificially created environments such as warehouses or buildings, and can cause damage to products. However, flora is predominantly found only in open-air spaces and can cause damage to products. Fungi and bacteria can be found in both open-air spaces and warehouses or buildings.

• The standard “EN IEC 60721-2-8 Part 2-8: Environmental conditions occurring in nature - Exposure to fire” describes the basic characteristics, characterization quantities, and environmental conditions relating to the occurrence, development, and spread of fire in a building, as well as electrotechnical products exposed to fire during stationary use. While this standard primarily addresses conditions before fire ignition, it also considers conditions following ignition. However, this standard has been superseded.
• The standard “EN IEC 60721-2-9 Part 2-9: Naturally occurring environmental conditions – Measured shock and vibration data – Storage, transport and use” is designed to define a strategy for arriving at an environmental characterization from measured data relating to a product’s life cycle. The aim of this standard is to define the essential characteristics and quantities for characterizing shock and vibration data during storage, transport and use as background material to the severity to which products may be exposed during these phases of their life cycles.
• The standard “EN IEC 60721-3-0 Part 3-0: Classification and intensities of environmental parameter groups - Introduction” provides guidance on the use of all parts of the IEC 60721-3 standard. This standard includes background information, including information on the application and limitations of the classes given in its various parts, which can be used in the design of equipment, the limitation of conditions, and protection.
• The standard “EN IEC 60721-3-1 Part 3-1: Classification and severity of environmental parameter groups - Storage” classifies the environmental parameter groups and their severity to which products are exposed (and their packaging, if any) during storage. The environmental conditions specified in this standard are limited to those that may directly affect the products or their final performance. Only environmental conditions are considered. No specific explanation is given regarding the effects of these conditions on the products themselves.

Environmental conditions directly related to fire or explosions are not included. Conditions for stationary use, portable and non-stationary use, use in vehicles and vessels, and transport are given in other sections of this standard. The purpose of this standard is to classify the environmental parameters and their severity to which a product may be exposed during storage. Transfer and handling during storage and transport are addressed in the EN IEC 60721-3-2 standard.

• The standard “EN IEC 60721-3-2 Part 3-2: Classification and severity of environmental parameter groups - Transport and handling” classifies the groups of environmental parameters and their severity to which a product is exposed during transport and handling. The most commonly used transport and handling methods have been taken into consideration:
• Road transport: cars, trucks
• Rail transport: trains, trams
• Water transport, inland water and sea transport: ships
• Air transport: airplane, jet, propeller plane, helicopter
• Handling equipment: cranes, hoists, cable cars, personnel.
• conveyors
• Wheelbarrows.

The environmental conditions specified in this standard are the conditions to which the product may be exposed during transport and handling. If the product is packaged, the environmental conditions apply to the packaging containing the product. If the product is unpackaged, the environmental conditions apply to the product. For storage conditions, the IEC 60721-3-1 standard applies.

• The standard “EN IEC 60721-3-3 Part 3-3: Classification and severity of environmental parameter groups - Stationary use in weather-protected locations” classifies the groups of environmental parameters and their severity to which products installed for stationary use in weather-protected locations are exposed. The environmental conditions specified in this standard are limited to those that can directly affect product performance. Only environmental conditions are considered. No specific explanation is given regarding the effects of these conditions on the products.

Explosion hazards, microclimate within the product, fire suppression, and environmental conditions directly related to ionizing radiation are excluded. Other unforeseen events are also excluded. The probability of these occurring may be considered as special circumstances. This standard does not cover equipment within the scope of building standards, regulations, or directives.

Conditions for fixed use in unprotected locations, portable and non-fixed use, use in vehicles and vessels, storage and transport conditions, and microclimates within the products are given in other sections of this standard. A limited number of environmental condition classes are given, covering a wide range of applications.

• The standard “EN IEC 60721-3-4 Part 3-4: Classification and severity of environmental parameter groups - Fixed use in unprotected locations” classifies the groups of environmental parameters and their severity to which products installed for fixed use in unprotected locations are exposed. For weather-protected locations where products can be permanently or temporarily installed for fixed use, the EN IEC 60721-3-3 standard applies.

The environmental conditions specified in this standard are limited to those that can directly affect product performance. Only environmental conditions are considered. No specific explanation is given regarding the effects of these conditions on the products. Environmental conditions directly related to fire or explosion hazards, conditions related to the microclimate within a product, and conditions related to the effects of ionizing radiation are excluded. Other unforeseen events are also excluded. A limited number of environmental condition classes covering a wide range of applications are given.

• The standard “EN IEC 60721-3-5 Part 3-5: Classification and severity of environmental parameter groups - Land vehicle installations” classifies the environmental conditions to which a product that is not part of the vehicle is exposed when mounted on a land vehicle. These products include radios, communication systems, toll meters, and flow meters for milk, petroleum products, and similar liquids transported by the vehicle. Vehicles on which these products can be permanently or temporarily mounted include:
• Land vehicles: passenger cars, commercial vehicles, private vehicles, tow trucks, trailers, mopeds, motorcycles.
• Rail transport: trains, trams, cranes.
• Land vehicles: four-wheel drive cars, tractors, snow scooters.
• Transport and storage equipment: forklifts (manual and robotic), baggage handlers.
• Self-propelled machines: excavators, combine harvesters.

Although this standard is not designed for products that form part of a vehicle, the environmental condition classification can be applied similarly to products that are not part of the vehicle, and to certain replaceable parts mounted in the same locations. Only severe conditions that could damage the products are included.

The purpose of this standard is to classify the environmental parameters and their severity to which a product will be exposed under operating conditions when mounted on land vehicles. A limited number of environmental condition classes are given, covering a wide range of applications. The user of this standard should select the lowest class required to cover each of the intended operating conditions.

• The standard “EN IEC 60721-3-6 Part 3-6: Classification and severity of environmental parameter groups - Ship environments” classifies the groups of environmental parameters and their severity to which a product is exposed when installed on a ship. Ships on which electrotechnical products can be permanently or temporarily installed include:
• Ships propelled by mechanical means, including mobile offshore units.
• Vessels not propelled by mechanical means, including sailboats and life rafts.

The defined classes apply to vessels of all sizes, from pleasure boats and trawlers to ferries, icebreakers, and cargo ships, including tankers. The areas in which vessels normally navigate are as follows:

• Inland waterways (canals, rivers, lakes)
• Coastal waters
• Oceans.

This includes areas where ships navigate through ice.

• The standard “EN IEC 60721-3-7 Part 3-7: Classification and severity of environmental parameter groups - Portable and non-stationary use” classifies the environmental parameter groups and their severity to which products are exposed during portable and non-stationary use, including transport, downtime, maintenance and repair periods. The environmental conditions covered by these groups are as follows:
• Environmental conditions in the locations where the product may be temporarily placed or used.
• Changes in environmental parameters due to relocation.
• Environmental conditions related to the transportation of the product between different locations.

The classified environmental conditions do not take into account the product's usage profile, i.e., whether the product is used only in a temporary stationary state, in transit, or arbitrarily. The portable and non-stationary usage conditions to which products may be exposed include land and offshore, weather-protected and unprotected locations. The conditions also include transportation, which is part of portable and non-stationary use.

The environmental conditions specified in this standard are limited to those that can directly affect product performance. Only environmental conditions are considered. No specific explanation is given regarding the effects of these conditions on the product.

Environmental conditions directly related to fire or explosion hazards and conditions related to ionizing radiation are excluded. Other unforeseen events are also excluded. In special circumstances, the probability of their occurrence should be considered.

• The standard “EN IEC 60721-3-8 Part 3-8: Classification and severity of environmental parameter groups - Stationary use in underground locations” classifies the environmental conditions to which products (equipment, systems, etc.) are exposed when installed and used in a stationary manner in underground locations (e.g., mines, tunnels, underground stations, basements, caves, underground vaults, etc.) and the severity of these conditions.
• The standard “EN IEC 60721-3-9 Part 3-9: Classification and intensity of environmental parameter groups - Microclimates inside products” classifies the microclimate groups to which components (core parts, assemblies, built-in units) inside products used in climate conditions classified in EN IEC 60721-3-3 and EN IEC 60721-3-4 standards may be exposed. The characteristic parameters of microclimates are high air temperature and high relative humidity. Other parameters of climate classes, such as low temperature, may also affect components, but are not addressed here. A limited number of microclimate classes are specified, taking into account the typical limiting high air temperatures of the components.
• The standard “EN IEC 60721-3-10 Part 3-10: Classification and severity of environmental parameter groups - Stationary use in underground mining installations” classifies the environmental conditions for equipment installed and used in stationary applications in underground mines (such as coal mines, salt mines, potash mines, and ore mines). This is a stricter and more specific standard compared to the more general underground standard EN IEC 60721-3-8. This standard takes into account the extremely challenging and potentially explosive conditions specific to underground mining environments (especially coal mines with methane/fireworks risks).
• The standard “EN IEC 60721-3-11 Part 3-11: Classification and severity of environmental parameter groups - Stationary use in underground sites with risk of explosion (excluding mining)” classifies environmental conditions for equipment permanently installed in underground sites with a risk of explosion but not classified as mining environments (i.e., not covered by the EC IEC 60721-3-10 standard). Typical examples of sites covered by this standard are:
• Underground oil, gas, and petrochemical storage caverns
• Underground hydrogen storage facilities
• Road and rail tunnels with possible fuel vapor or gas leaks.
• Underground parking lots where LPG/CNG vehicles are located
• Underground waste treatment or biogas plants
• Military underground fuel depots
• All underground cavities where flammable gases or liquids are stored or processed (excluding mines)

These areas are not included in mining activities.

• The standard “EN IEC 60721-3-12 Part 3-12: Classification and intensities of environmental parameter groups - Fixed use in underground locations with seismic activity” classifies environmental conditions for equipment permanently installed in underground locations where seismic load is a significant design factor. It is used in cases where the underground structure is designed to withstand earthquakes (e.g., deep tunnels, underground stations, caverns, underground data centers, particle accelerator tunnels, underground laboratories, military bunkers) and the equipment within it must withstand the same seismic event as the structure. This standard is not intended for surface or above-ground installations. It is also not intended for mining or non-mining explosive environments.
• The standard “EN IEC 60721-3-13 Part 3-13: Classification and intensities of environmental parameter groups - Stationary use in extremely cold underground locations” classifies environmental conditions for equipment permanently installed in permanently or seasonally extremely cold underground locations. It is designed for locations where, due to the natural arctic/Antarctic climate or high-altitude deep rock conditions, the air temperature regularly drops well below -40 degrees (-60 degrees or lower), even when the location is underground. Typical real-world locations covered by this standard include:
• Deep underground laboratories in Arctic regions
• Ice caves and subglacial laboratories
• Deep tunnels in permafrost at high altitudes
• Cryogenic underground storage caverns
• Underground neutrino detectors or dark matter tests in very cold rocks.
• Military or scientific facilities located under permafrost

This standard is not suitable for normal underground locations or refrigerated rooms (man-made, not naturally excessively cold).

• The standard “EN IEC 60721-3-14 Part 3-14: Classification and intensity of environmental parameter groups - Stationary use in extremely hot underground locations” classifies the environmental conditions for equipment permanently installed in naturally extremely hot underground locations where rock temperatures are consistently high due to geothermal gradient, depth, or location in hot climate zones. Typical locations covered by this standard include:
• Very deep mines (large gold, copper, and diamond mines at depths of 3-5 km, for example, gold mines where the temperature of the pure rock exceeds +50 to +65 degrees Celsius).
• Geothermal energy facilities (deep drilling, hot dry rock projects).
• Deep scientific drilling and underground laboratories in hot regions
• Ultra-deep oil and gas tunnels or caverns.
• Future deep radioactive waste repositories in hot rock formations.

This standard is not suitable for normal depth underground and artificially heated areas.

• The standard “EN IEC 60721-3-15 Part 3-15: Classification and intensities of environmental parameter groups - Stationary use in underground locations with very high electromagnetic interference (high EMI/EMC stress)” classifies the environmental conditions for equipment permanently installed in underground locations where extremely strong electromagnetic disturbances exist, far beyond those seen in normal underground sites. Typical locations covered by this standard include:
• Underground particle accelerator tunnels.
• Underground high-energy physics laboratories containing large magnets and RF cavities.
• Deep underground pulsed power plants.
• Underground high-voltage DC converter stations in caves.
• Underground magnetic confinement fusion experiments.
• Military underground EMP-resistant command centers that have been deliberately tested at high altitudes.
• Underground linear accelerators for medical or safety purposes.

These locations typically have very high electromagnetic fields, either intentionally or unavoidably, along with radiation, vibration, and rigorous cleaning requirements.

• The standard “EN IEC 60721-3-16 Part 3-16: Classification and intensities of environmental parameter groups - Stationary use in underground locations with very high ionizing radiation levels” classifies environmental conditions for equipment permanently installed in underground locations where natural or man-made ionizing radiation is significantly higher than at the surface and this radiation level is a dominant design factor. This standard is not related to normal background radiation or short-term exposure during transport. It is specifically designed for long-term stationary operation in high-radiation underground environments.
• The standard “EN IEC 60721-3-21 Part 3-21: Classification and intensities of environmental parameter groups - Stationary use in underground data centers and underground telecommunication installations” is the first and only part of the IEC 60721-3 standard series specifically designed for modern underground data centers and underground telecommunication nodes. This standard covers installations intentionally placed underground for the following purposes:
• Physical security
• Natural cooling (constant rock temperature)
• EMP/HEMP provides protection against storms, floods, or sabotage.
• Very low latency (exit locations near cities)
• Facilities deliberately placed underground for regulatory or aesthetic reasons.

For many years, our organization, with its competent and experienced staff, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting them in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services to businesses in accordance with the "EN IEC 60721 Classification of Environmental Conditions" standard.