Types of Respirators Cartridge Warning Properties
{"Image DocumentName": "Types of Respirators Cartridge Warning Properties", "Image ImageDescription": "Contaminants must have warning properties. Smell, taste, or breathing irritation. Warning properties differ for each contaminant. Odour threshold. For respirators fitted with gas and vapour cartridges to be used safely, the contaminant must have warning properties that will let you know if the cartridge is no longer working. You must be able to sense the contaminant (by smell, taste, or breathing irritation) when it starts to penetrate the cartridge. Otherwise, you will not know when you are breathing it. An exception is that cartridges can be used for escape even if the warning properties are poor. Different contaminants have different warning properties. Some gases and vapours have poor warning properties. Odour can sometimes be used as a warning property. Be aware that different contaminants have different odour thresholds. Odour threshold is defined as the lowest concentration of a contaminant in the air that can be detected by the human sense of smell. If you are relying on odour as a warning property, the odour threshold of a contaminant must be below its exposure limit. The exposure limit is the maximum concentration of a contaminant that workers are allowed to be exposed to without respiratory protection. When comparing odour threshold to the exposure limit, always use the 8-hour time-weighted average (TWA) limit, where there is one, even if the substance has a short-term exposure limit or a ceiling limit listed as well. If a substance has only a ceiling limit, then use the ceiling limit. Odour thresholds are often given as a range because people differ in their ability to detect odour. It is important to look at the upper end of the range in order to protect all workers. For example, both styrene and acetic acid are smelled well before the concentration gets close to the 8-hour TWA limit. Workers would smell the contaminant when it starts to break through the chemical cartridge. With chloroform, however, by the time the concentration is high enough for the worker to smell, the contaminant level is above the 8-hour TWA limit and the worker has been overexposed. With methanol, some workers in certain environments will smell methanol before the 8- hour TWA limit is reached. For most workers, the concentration will exceed the 8-hour TWA limit before they can smell methanol. Therefore, workers cannot use air-purifying respirators to protect themselves against chloroform and methanol.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}