What are the acceptable standards for vinyl chloride during work in confined spaces?
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1) Clause 6.2 of GB30871-2014 stipulates that for toxic gases in confined space operations, the standards set out in GBZ2.1-2007 shall apply; the PC-TWA for vinyl chloride is 10 mg/m3, with a tolerance factor of 2, and its short-term exposure limit should not exceed 20 mg/m3. 2) According to 7.3.1.1 of GB14544-2008, before entering the reactor, the volume fraction of vinyl chloride inside the reactor shall not exceed 0.2%, which is approximately 5200 mg/m3. 3) Both of the clauses cited above are mandatory provisions of this standard. 4) Most enterprises adhere to the 30mg/m3 standard specified in GB14544-1993. What are everyone's opinions?
The 2014 standards should be implemented
It is better to follow the provisions of Article 6.2 of GB30871-2014: for work in confined spaces, toxic gases must comply with GBZ2.1-2007; the PC-TWA for vinyl chloride is 10 mg/m3, with a tolerance factor of 2, and its short-term exposure limit should not exceed 20 mg/m3
GBZ2.1-2007 referenced in GB30871-2014
Personally, I understand it this way: what the original poster needs to be clear about is that GBZ2.1-2007 is a standard for exposure to occupational hazards; it specifies the maximum duration for which workers can be exposed without wearing protective equipment, without it causing poisoning； GB14544-2008 is a set of safety and operational procedures for inspection, maintenance, and repair work. When carrying out such tasks, and due to limitations in the working conditions on site, it is possible to perform welding or other operations involving flammable gases such as vinyl chloride either while wearing protective equipment or without it. The standard specifies that the concentration of these flammable gases must not exceed 0.2%, as the explosive limit is below 4%; this requirement is in place to ensure safe performance of inspection, maintenance, and repair tasks.
You had better take a look at 7.2.1.2 of GB14544-2008 first
Article 6.2 of GB30871-2014 stipulates that for toxic gases in confined space operations, the requirements set out in GBZ2.1-2007 shall apply; the PC-TWA for vinyl chloride is 10 mg/m3, with a tolerance factor of 2, and its short-term exposure limit shall not exceed 20 mg/m3.
It poses a serious threat; it’s best to deal with it thoroughly during the operation