คำตอบที่ 1
จากหนังสือเขาว่ามา บอกว่า ค่าสูงสุดที่คนจะรับได้คือ ระหว่าง 8-10 ppm
สำหรับการทำงานวันละ 8 ชม ต่อ สัปดาห์ครับ (Horikawa ,2001)
7.2.1 Introduction :
Hydrogen Sulfide (H2 S) is one of the most toxic dangerous gases in the oil and gas industry.
It is absolutely essential that all employees have a clear understanding of the very hazardous nature of H2S, the recognition of its presence,
and the procedures to be followed in order to protect themselves from its lethal effect if H2S is released into the atmosphere.
H2S may be released into the atmosphere during operations such as drilling, draining, venting, sampling and
when process equipment or pipe work is opened for maintenance work.
It can also be released to the atmosphere due to the leakage of crude oil or natural gas containing H2S.
The purpose of this code of safe practice is to aid the understanding of all personnel and to clarify safe working procedures
for personnel who may be exposed to H2S. H2S KILLS SO BE AWARE - BE SAFE
7.2.2 H2S Properties & Toxicity
H2S is a highly toxic gas. It is colorless and is heavier than air; however it is readily dispersed by wind movement.
It is flammable and, if ignited, will burn with a blue flame, producing Sulfur Dioxide (SO2) an irritating and also very toxic gas with a pungent odor.
H2S has a characteristic 'rotten eggs' odor, which can be smelled in Concentrations as low as 0.1 part of gas per million parts of air by volume (ppm).
DO NOT DEPEND ON SMELL TO DETECT H2S.
The odor is very unreliable way of detecting this poisonous gas since at concentrations between 100-150 ppm, the sense of smell is rapidly deadened.
At low concentrations, H2S causes irritation to the eyes, nose and throat, and in high concentrations can be rapidly fatal due to lung paralysis.
The Threshold Limit Value (TLV) is the time weighted average concentration
for an 8 hours a day or 40 hours a week to which nearly all workers may be repeatedly exposed without adverse effect.
The TLV for H2S is 10 ppm.
ผมเคยดมแกสจากบ่อไปโอแกส ที่ผ่านการกำจัดแกสไข่เน่าแล้วจนเหลือในปริมาณที่เครื่องจักรับได้ หายใจเข้าไปแค่ครั้งถึงกับหน้ามืด เวียนหัว
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