Classified areas: what they are and why they are important.

In the industrial environment, operational safety is the foundation of any activity. Among the technical challenges faced by managers and electricians are... classified areas They require extra attention. A specification error in these areas can be the trigger for serious accidents.

But what defines these spaces, and how do you ensure that the electrical installation doesn't become a point of ignition? Below, we detail everything you need to know to keep your building within regulations.

What are classified areas?

According to the standards NR 10 e NR 20Classified areas are locations where there is a probability of formation of a explosive atmosphereThis happens when flammable substances mix with oxygen in the air in proportions that allow combustion.

For an explosion to occur, three factors must come together:

1. Fuel: Gases, vapors, mists or dusts (such as sawdust, sugar or grains).
2. Oxidizing: The oxygen present in the air.
3. Ignition Source: An electric spark, excessive heat, or static electricity.

The classification serves precisely to ensure that the electrical equipment installed on the premises is designed for prevent that this ignition occurs.

How do I know if an area is classified?

Identifying a hazardous area isn't done by guesswork. It depends on a technical study that assesses the company's inventory of substances. If volatile products are handled, stored, or processed, classification is mandatory.

Some points that indicate the need for this study:

• Presence of flammable liquids (solvents, fuels).
• Use of gases (hydrogen, LPG, ammonia).
• Processes that generate clouds of fine dust (grinding, sanding, grain transport).

If there is a chance that these substances could escape into the environment during normal operation or in the event of a failure, the location should be mapped as a classified area.

How is a classified area defined?

The definition of the areas follows criteria of frequency and duration of risk. In Brazil, the system of Spaces This is the standard used to classify hazards:

Gases and Vapors (Zones 0, 1 and 2)

• 0 zone: An explosive atmosphere is present continuously or for extended periods (e.g., inside a tank).
• 1 zone: The risk is likely to arise under normal working conditions (e.g., near filling nozzles).
• 2 zone: The risk is unlikely in normal operation. If it does occur, it is short-lived (e.g., around flanges and valves).

Dusts and Fibers (Zones 20, 21 and 22)

• 20 zone: A cloud of explosive dust is permanently present.
• 21 zone: Occasional dust cloud formation during normal operation.
• 22 zone: Rare or very short-lived presence of layers or clouds of dust.

This classification indicates what type of protection the equipment must have. A motor certified for Zone 2, for example, cannot be used in Zone 1.

What is a classified area report?

O Classified Areas Report It is the engineering document that formalizes the entire site analysis. It is a legal requirement for compliance with workplace safety standards.

This document should contain:

• Classification Plants: Maps that show exactly where each zone begins and ends.
• Substance Data: Technical data sheets with flash point and explosive limits.
• Extension Calculations: Determining how far the gas or dust can spread.

Without this document, the company is vulnerable to fines and, worse, runs the risk of installing inadequate electrical materials that could fail at a critical moment.

Electrical Standards and Materials that ensure safety

To operate in these locations, it's not enough to use just any material. It's necessary to use products with the "Ex" mark, which indicates explosion protection. The main guidelines are... NR 10, NR 20 and the technical standard ABNT NBR IEC 60079.

Common Types of Protection

• Explosion-proof (Ex d): The equipment can withstand an internal explosion without allowing it to escape to the outside.
• Enhanced Security (Ex e): Designed to not generate sparks or heat above permitted levels.
• Intrinsic Safety (Ex i): It operates with such low energies that the spark generated does not have the strength to cause an explosion.

Examples of Essential Equipment

• LED light fixtures Ex: Sealed against gases and resistant to impacts.
• Shielded Plugs and Sockets: Featuring locking systems that prevent disconnection under load.
• Cable glands and junction boxes: Made from materials such as aluminum or antistatic fiberglass to prevent the buildup of energy.

Practical care and maintenance

Having the right equipment is only half the battle. Safety depends on rigorous maintenance. Some fundamental practices:

1. Cleaning: In dusty areas (Zones 21 and 22), accumulation on equipment can cause overheating.
2. Seal Check: Any loose screw in an explosion-proof enclosure negates the protection.
3. Grounding: Essential for dissipating static electricity, one of the biggest culprits in industrial explosions.
4. Training: Only professionals with specific training in classified areas should work on the electrical system in these locations.

Alutal assists in the security of Classified Areas.

Ensuring the integrity of an industrial plant requires partners who are experts in technical standards and offer cutting-edge technologies. Total It directly supports this, providing instrumentation and monitoring solutions that meet the strict safety criteria required in Zones 0, 1, or 2.

Whether in the specification of sensors for critical processes Whether it's ensuring accurate measurements in environments with flammable vapors, our expertise helps your company mitigate risks and maintain compliance with NR 10 and NR 20 standards. Choosing certified components is the final step in transforming your inspection report planning into a safe and productive operation in practice.

Following these rules is not just a matter of avoiding fines, but of ensuring everyone gets home safely at the end of their shift. At Alutal, we emphasize that technical knowledge and the choice of certified components are the best investments against explosion risks.