Understanding Gas Sensor Response Time: Why Comparisons Aren’t Easy

A gas sensor's response time refers to how long it takes to detect and report the presence of a gas. However, it is a bit more complicated than that. Response time is typically defined as the time required for a sensor to reach a specific percentage of its final reading after exposure to a target gas. This is often measured as “T90” - the time it takes the sensor to reach 90% of its final value. Some companies use T50 (50%), and T63 (63%) is also a common standard.

Although comparing response times is important, it can be challenging. Here's why:

• No Universal Rules:
  As mentioned, there is no single standard for measuring response time. One company might use T90, another T50. This could cause users to make invalid comparisons. Even two sensors of the same type can behave differently under similar conditions.
• Varying Test Conditions:
  Response time is influenced by factors such as gas concentration, temperature, humidity, air pressure, and gas flow rate. Additionally, differences in testing setups, such as the size of the test chamber, can significantly affect the results.

Imagine a gas entering an area monitored by a gas sensor. It takes the sensor a while to notice anything is wrong at all, and to register an initial reaction. Then it takes more time to fully respond and report just how much gas is there (90%, or 63%, or 50% of the total value, for example). Finally, when the gas is eventually gone, it takes more time for the sensor to recover and report that the
gas amount is zero.

• Reaction Time: The time it takes to detect the initial presence of gas.
• Response Time: The time to reach a significant percentage of the final reading.
• Recovery Time: The time for the sensor to return to baseline after the gas is gone.

It can be difficult to determine whether a sensor is fast enough for your application or to accurately compare different sensor options. Micro-Hybrid has extensive experience in designing and customizing gas sensors to meet each customer’s specific requirements. From initial concept to final implementation, we will support you throughout the entire integration and deployment process of Micro-Hybrid gas sensors. We can develop a tailored, cost-effective solution optimized for your needs. Contact us today to find out how to take your gas measurements into new spaces.