Toxic gas alarm

You can ask Delge, MSA, New Universe, or Kolkon; you can also check out our website at www.ai-a.cn.

MAC 30mg/m3, LDLH 500ppm, for reference only

Ammonia is a Category IV toxin, primarily causing irritation and corrosion to the respiratory tract. Ammonia reacts with the moisture in moist areas of the human body to produce high-concentration ammonia solutions, which can cause alkaline burns to the skin; if it gets into the eyes, it can lead to blindness. At high concentrations, it can increase the excitability of the central nervous system, leading to spasms, and through reflex actions at the trigeminal nerve endings, it can cause cardiac arrest and respiratory failure. The human olfactory threshold for ammonia is 0.5–1 mg/m3. It is impossible to work in areas with levels above 350 mg/m3. The maximum allowable concentration of air in the workshop is 10 mg/m3. The first-level alarm threshold is 75% of this maximum allowable concentration, while the second-level alarm threshold is 10% of the concentration at which harm occurs. Based on this, the first-level threshold should be 10×75% = 7.5 mg/m3. Of course, this threshold can be relaxed when dealing with outdoor environments. Typically, the measurement range for toxic gases is set between 0 and 30, without much distinction between different gases; however, a more detailed classification is actually necessary. For your second level, I’m not sure what constitutes direct harm. I think that if, for example, being in contact for 20 minutes results in significant discomfort, then that could be defined as 200; 10% would correspond to 20. I recommend this as the best answer! ! !

First, let’s correct a common misconception: ammonia does not have a MAC value; it has PC-STEL and PC-TWA values. Secondly, for the setting of alarm values for toxic gases, the following three standards can be referred to: GB50493-2009 \"Design Code for Detection and Alarm of Flammable and Toxic Gases in Petrochemical Industries\", GBZ/T 223-2009 \"Code for Installation of Detection and Alarm Devices for Toxic Gases in Workplaces\", and AQ3036－2010 ； The alarm value settings specified by these three standards seem to differ, but there is no actual conflict between them. When considering these three criteria together, two levels can be set for the ammonia alarm threshold: the first level is the alarm value (75% of PC-STEL), at which point the personnel on duty should immediately locate the source of release and take appropriate measures to prevent further release as well as to protect the people involved ； The second level represents an overreported value (which must not exceed 10% of the direct harmful concentration LDLH); it indicates that the ammonia release has reached a dangerous level, and emergency procedures should be initiated promptly to ensure the protection of workers on site and their evacuation. Once again, the permissible concentration for short-term exposure to ammonia is PC-STEL at 30 mg/m3, while the concentration that causes immediate harm is LDLH at 360 mg/m3. Finally, convert mg/m3 to ppm: the first-level alarm value is 32 ppm ； The secondary high reporting value is 50 ppm

Additionally, the strictest setting for the alarm level is three stages: the first-stage warning value is 21 ppm, the second-stage alarm value is 42 ppm, and the third-stage high-warning value is 87–126 ppm. For the specific calculation process, please refer to the previous response; it is omitted here.

I learned it! May I ask how to convert mg/m3 to ppm?

mg/m3 divided by the molecular weight, then multiplied by 24. 24 is the molar volume of a gas at 20 degrees Celsius; be careful not to multiply by 22.4. For the specific process of simplifying expressions, write it out more times on paper with a pen, and you’ll figure it out.

. . . It seems I set it too low, haha