The EN343 standard is a European norm that specifies the requirements for protective clothing, particularly focusing on protection against rain, snow, fog, and ground humidity. This standard ensures that clothing provides adequate protection from wet and cold conditions in outdoor environments, making it vital for people working in harsh weather conditions, such as construction workers, road workers, and outdoor labourers.

EN343 evaluates clothing based on two main factors:

Water Resistance (X): This measures how well the fabric resists water penetration. It is classified into three levels:

• Class 1: (least water-resistant): Garments can withstand light rain but may allow some water penetration over time. 
• Class 2: Offers moderate resistance and can handle medium-intensity rain. 
• Class 3: (most water-resistant): Provides the highest level of protection, ideal for heavy rain and long-term exposure. 

Breathability (Y): This indicates the garment's ability to allow sweat and moisture to escape from the inside. It’s also classified into three levels based on the Ret value, which measures the resistance to water vapour transmission: 

• Class 1: (Ret > 40): Least breathable, which may cause discomfort over time due to heat and sweat build-up. 
• Class 2: (Ret between 20 and 40): Moderate breathability for regular use. 
• Class 3: (Ret < 20): Most breathable, offering the best comfort in physically demanding situations.

Garments conforming to EN343 standards are typically marked with the EN343 symbol followed by two digits (X and Y) that represent the performance in water resistance and breathability, respectively.