| the term | meaning |
| LEL | Abbreviation for "LowerExplosiveLimit", Chinese is the lower explosion limit. Refers to the lowest concentration at which a flammable gas is mixed with air at an ignition point. |
| Ppb | One billionth of a gas concentration. ※1ppm=1000ppb |
| Ppm | One millionth of the gas concentration. ※1%=10000ppm |
| TLVs | Abbreviation for "ThresholdLimitValues", Chinese is the allowable concentration. Refers to the concentration of harmful substances that almost all workers do not consider to have a detrimental effect on health even if they are repeatedly exposed to hazardous substances for several consecutive days. It can be divided into TLV-TWA, TLV-STEL, TLV-C, etc., and its specific value is determined by ACGIH. |
| TLV-TWA | Short for "Threshold LimitValueTimeWeightedAverage", Chinese is the time-weighted average violent limit value. This refers to the weighted average concentration of harmful substances that does not have a health adverse effect on almost all workers, even in repeated daily exposure to hazardous substances, in daily work for 8 hours a day or 40 hours a week. |
| TLV-STEL | Short for "Threshold LimitValueShort TermExposureLimit", Chinese is the short-term violent limit value. This refers to a hazardous substance that does not cause a health adverse effect on workers if the worker is exposed to harmful substances for 15 minutes and the daily exposure to harmful substances is lower than TLV-TWA. concentration. |
| TLV-C | Abbreviation for "Threshold LimitValueCeiling", Chinese is the limit value of the violent limit. This refers to the concentration of harmful substances that workers must not exceed even when they are exposed to hazardous materials. |
| Vol% | Refers to the volume concentration ratio of the gas. |
| Response time | When the concentration of the test gas changes instantaneously, its indicated value is controlled within the specific range of the final value. |
| Overhaul | It refers to the inspection and repair of the inside of the machine for maintenance inspection. |
| Flammable gas | A gas that can be burned in the air or in oxygen. |
| Sensitivity | Feel the extent of changes in gas concentration. |
| Sensitivity check | It refers to the use of a certain concentration of gas to confirm the output action of the gas detection sensor. |
| Gas alarm | An alarm is issued that detects a certain amount of gas concentration. |
| Gas detection | Quantitative detection of gas concentration |
| Allowable concentration | When the worker is working in a place exposed to harmful substances, if the concentration of the substance in the air is below this value, it can be judged that the concentration will not be adversely affected by health for almost all workers. This concentration is the recommended value proposed by the Japan Industrial Hygiene Society. |
| Repeatability | The same measurement method was used in which the respective measured values ​​obtained by repeatedly measuring the same gas to be detected under the same conditions and in a relatively short period of time were identical. |
| Detection target gas | The gas concentration is detected, and if there is an indication or an alarm, it is the target gas. |
| Detection principle | The principle of detecting a gas and converting it into an electrical signal. |
| Change over time | It refers to the change in the characteristics of the gas detector generated over time. |
| Alarm delay | It is the time required to reach the alarm when a certain concentration of gas above (or below) the alarm set value is detected. |
| Alarm accuracy | It is the difference between the alarm set value and the gas concentration at the start of the alarm or the percentage expressed by the difference between the difference and the alarm set value. |
| Detection accuracy | It refers to the comprehensive performance of the correctness and accuracy of the displayed value (or the measured result indication value) by the gas detector. |
| examination range | It refers to a concentration range of a gas to be detected which can indicate a gas concentration and an alarm occurs. |
| Alarm setting | It is a value that is set to give an alarm when the gas concentration reaches a certain concentration. |
| Correction | Using the calibration gas or the like, the relationship between the indication value, the display value, or the set value of the machine and each true value is obtained. |
| Calibration curve | A curve of the correspondence between the gas concentration and the indicated value. |
| Calibration gas | It is a gas used for gas calibration alarms. It is a general term for gases such as zero gas, interval gas, and calibration gas. |
| Maximum scale value | The maximum value of the measured amount displayed on the scale. |
| Operating temperature range | Refers to the temperature range over which the gas detector maintains its performance/function. |
| Indication range | The range that the indicator can display. |
| Pressure-resistant explosion-proof structure | This means that when an explosive gas explosion occurs inside the container, the structure of the container belonging to the fully enclosed structure can withstand the pressure generated by the explosion, and there is no fear that the explosion inside the container will ignite the external flammable gas. |
| Warm up time | It refers to the time required after the gas detection alarm is turned on to meet the normal operation of the detection alarm. |
| Linearity | It means that the linear relationship between the gas concentration and the output value is not much different. |
| Regular inspection | It is the inspection and maintenance of the machine during the specified period. |
| Battery life | The specified performance and duration of the function can be maintained while the gas detector is operating normally under the specified conditions of use. |
| Daily check | Daily inspection and maintenance of the machine |
| Concentration indicator | It is an instrument that displays the measured amount of gas concentration or the like in an analog or numerical manner. |
| Explosion range | A range of concentrations in which a flammable gas is mixed with air and caused by an explosion. |
| Lower explosion limit (LEL) | The flammable gas is mixed with air and the lowest concentration produced by the explosion. English is "Lower Explosion Limit" |
| Upper explosion limit (UEL) | The flammable gas is mixed with air and the highest concentration of ignition is caused by the fire. English is "Upper Explosion Limit". |
| Peak | Refers to the maximum or minimum value at a certain time. |
| Peak hold | It refers to the function of frequently updating and maintaining the peak value of the input signal. |
| average value | It is a value obtained by adding all the measured values ​​to the measured sample and dividing by a certain number. Measured value |
| Basic stability | It refers to the change of the basic value relative to a certain or surrounding condition, and is not affected to a large extent. |
| Correction | It refers to the read value, set value, or calculated value to be added in order to save the value closer to the real value, or the above value. |
| Maintenance check | Work performed to maintain the functions required for normal machine use. |
| Intrinsically safe explosion proof structure | This refers to an explosion-proof structure that is confirmed by the public agency through the ignition test and other tests. The structure does not ignite the explosive gas in the electric spark or high temperature part generated during normal time and accident. |
| Interference gas | Gases other than the detected target gas have an influence on the indicated value and the alarm concentration. |
| Explosion-proof structure | In an explosive atmosphere, ignition inside the machine does not ignite the structure of the external explosive gas. There are "pressure explosion structure", "intrinsic safety explosion-proof structure" and "internal pressure explosion-proof structure". |
| %LEL | The lower explosion limit concentration of the combustible gas is taken as 100, and the concentration of the combustible gas is expressed in units of one hundredth. |