硫化氫監測器之評估

Evaluation of Hydrogen Disulfide Gas Monitors

由於硫化氫在國內已導致多起中毒死亡災害，而直讀式儀器具有立即讀取硫化氫氣體濃度值的優點，是十分恰當的安全設備。國內的直讀式硫化氫監測器大多仰賴國外進口，在使用環境不同的情況下，其讀值是否可靠、功能是否完備，目前尚缺乏完整數據。因此進行直讀式硫化氫監測器評估，期望對目前工業界廣泛使用的硫化氫監測器有更進一步的了解。所有評估項目大約包括三大類：基本性能測試、物理性因素影響、化學性因素影響，共計十五個測試項目。本研究以所取得之三種廠牌攜帶式的硫化氫氣體監測器為研究測試載具。由於硫化氫具有急毒性，所以快速發出警報是相當重要的特性，在警報時間測試項目中，“A”表現最佳，僅需7秒鐘即可發出警報。但若考慮誤警頻率的高低，“B”基本性能測試中表現較佳，且較不受物理性因素影響，所以，“B”發出錯誤警報的機率應該較低。至於化學性因素影響測試，三種呈現相同的結果，皆不受甲烷氣體的干擾，但暴露過高濃度之硫化氫氣體後，讀值有偏高的傾向。因此，消費者在選購硫化氫氣體監測器時，快速發出警報時間是不可缺少的基本特性，物理因素影響的降低是減少誤警發生的必須要求。

Hydrogen sulfide (H2S) has caused a number of accidents and deaths in Taiwan recently. A direct reading type monitor, which can read out hydrogen sulfide concentration directly, is a very suitable device. However, majority of direct reading type H2S monitors in Taiwan are imported which results in insufficient data to verify their functions and reliability in different operating environment. This study focuses on evaluation of some direct reading type H2S monitors in order to have an in-depth understanding of the H2S monitors which are widely used in the industrial circle. The evaluation is consisted of 15 tests in three basic categories; performance characteristics, physical factor effects, and interference.. In this study, three portable H2S monitors of different brands were tested. Since H2S is acutely toxic, prompt alarming is an important feature. In the alarm timing test, brand 'A' demonstrated the best performance, it gave an alarm in only 7 seconds. But if one taks the error rate into consideration, brand 'B' performed the best in the performance characteristics test, and exhibitted fewer physical factor effects. Therefore, brand 'B' has the lowest possibility of yielding false alarms. As for chemical interferences, all three brands showed similar results. Methane did not cause interference, but their readings tended to be higher when they were exposed to extremely high H2S concentration. Hence in the selection of H2S monitors, prompt alarming is an indispensable basic feature, and less physical factor effect is a requirement to minimize the generation of false alarms.