Hazard protection guidance

Online Editor

Rhys Redrup discusses the potential hazards linked with unproven technology.

The gas detection market is subject to a variety of standards that outline the requirements for different types of gas detectors in various environments. Stringent regulations are in place for detectors used in potentially explosive atmospheres. These standards also establish criteria for sensitivity, range and measurement uncertainty. However, it is worth noting that the accuracy performance standards for gas detectors are not as strict as those for gas emissions analysers. This discrepancy arises from the fact that emissions analysers are primarily used to ensure compliance with environmental limits for individual gases, whereas gas detectors are commonly employed for safety purposes to detect a wide array of gases.

It is important to highlight that instruments equipped with photoionisation detection (PID) sensors offer precise measurements of specific volatile organic compounds (VOCs), especially when those VOCs are present in isolation or have been selectively sampled.

Although independent verification of performance characteristics such as range, response time and measurement is mandatory for environmental emissions compliance monitoring, according to USEPA, MCERTS, TUV and other relevant bodies, the same requirement does not apply to gas detectors. Consequently, users should exercise caution regarding claims made by suppliers that lack an established reputation for accuracy and reliability.

In gas detection applications, where safety is of utmost importance, the longevity and reliability of instruments are crucial. However, these performance characteristics are not specifically addressed in the standards. Instead, users are responsible for regular calibration, servicing and adherence to manufacturers’ instructions. Consequently, reputable manufacturers earn their standing through the positive experiences of field users. Therefore, users should approach claims of longevity and reliability from unproven suppliers with caution.

Primary focus

The primary performance requirement of VOC detectors is their capability to detect potentially hazardous VOCs at extremely low concentrations. However, considering the diverse range of VOCs present across industries and locations, it is impractical for instrument manufacturers to publish accuracy and sensitivity data for every individual VOC due to their sheer number. Instead, manufacturers commonly disclose sensitivity values for a calibration gas, such as isobutylene. Additionally, manufacturers should provide response factors for numerous commonly encountered VOCs, as well as for each type of PID lamp they offer.

PIDs are highly sought-after and well-suited sensors for measuring VOCs in health and safety applications. Their popularity stems from the rapid response time and exceptional selectivity towards VOCs.

Ion Science develops and manufactures the MiniPID sensor, which has been independently verified as the best performing solution for speed, accuracy and resistance to both humidity and contamination. The MiniPID sensor is used in a range of the company’s gas detectors, providing each product with optimal performance even in humid and heavily contaminated atmospheres.

Rhys Redrup is with Ion Science

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