Common Terminology for Portable Gas Detectors

1. IDLH (Immediately Dangerous to Life or Health Concentration): Refers to the concentration of air pollutants in a hazardous environment reaching a dangerous level that could be fatal, cause permanent health damage, or immediately impair escape ability. IDLH values are measured in ppm (parts per million).
2. PEL (Permissible Exposure Limit): The concentration at which workers can be repeatedly exposed for 8 hours per day and 40 hours per week without adverse health effects. PEL values are measured in ppm.
3. ppm (Parts Per Million): The most commonly used unit for measuring toxic gases. 10,000 ppm = 1% by volume, and 1 ppm = 1000 mg/m³.
4. TLV (Threshold Limit Value): Reference values for harmful gas concentrations that workers can endure during daily work hours. There are three types: ① TWA (Time-Weighted Average): The average concentration of harmful gases a worker can be exposed to over an 8-hour workday, 5 days per week. ② STEL (Short-Term Exposure Limit): The maximum concentration a worker can be exposed to for 15 minutes without harm. This limit must not occur more than 4 times daily, with intervals of at least 60 minutes between exposures. ③ C (Ceiling Limit): The absolute maximum concentration that must never be exceeded, taking precedence over TWA and STEL.
5. LEL (Lower Explosive Limit): The minimum concentration of combustible gas required to trigger an explosion in a space. %LEL is the standard unit for detecting combustible gases.
6. UEL (Upper Explosive Limit): The maximum concentration of combustible gas that can cause an explosion. Concentrations above UEL result in insufficient oxygen to sustain combustion.
7. Oxygen-Deficient Atmosphere: A condition where oxygen levels fall below 19.5% by volume, leading to breathing difficulties.
8. Oxygen-Enriched Atmosphere: A condition where oxygen levels exceed 22% by volume, increasing the risk of explosions.
9. Cross Sensitivity: Sensor output is determined by chemical reactions, which may cause responses to gases other than the target gas. This phenomenon is called cross sensitivity. Users must consult cross-sensitivity tables provided in product manuals when selecting equipment.
10. IP Rating (Ingress Protection): A classification for electrical equipment enclosures against intrusion by foreign bodies and water. The first digit indicates protection against solids, and the second digit indicates water resistance.

Solid Particle Protection

Water Protection