When testing for the presence of H 2 S in a confined space, you MUST test the BOTTOM of the tank or space. When gauging or sampling, always stand upwind of the gauge hatch, even if test results indicate low H 2 S readings. Be especially careful on very calm days. When working sour crude or other known or suspected H 2 S contaminated material, you must establish the level of H 2 S contamination of each tank prior to commencement of any other type of work. You are required to wear a SCBA respirator while performing this test function. Refineries are not the only industrial sources of H 2 S. It can be found on drilling rigs, pulp mills, leather tanning factories, iron and steel mills, viscose rayon plants, sewage treatment facilities and any agricultural facility where rot, mildew and decay of organic matter might occur. Some crude oils are known to have very high levels of H 2 S. However, all crude oils and fuel oils have the potential of having very high levels. Readings as high as 64,000 ppm have been recorded. These are extremely dangerous levels which could be fatal almost instantaneously. Additionally, the head space of a crude oil cargo is frequently a mixture of inert gas and H 2 S. These two in combination are even more dangerous.
The hazards associated with confined spaces fall into the following groupings: Oxygen Deficiency. Flammable or Explosive Mixtures. Toxic Atmosphere. The purpose of this section is to describe what a confined space is and to advise you that this level of training does not include the requirements of confined space entry and that you are not authorized to enter confined spaces until such time as you receive the required training. 1.6 Static Electricity This section addresses the hazards associated with static electricity, along with various measures that should be taken to prevent or reduce the associated risks. There is not a lot that can be done to prevent the generation of static electricity. The inspector has little control over the speed at which a product is pumped through a pipeline and winding up tapes or lowering thermometers into tanks is an unavoidable part of the daily routine.
1.5 Confined Space Entry Confined spaces pose a special and particular hazard to those employees that are required to work in them. A confined space is designated as having one or more of the following characteristics: Limited openings for entry and exit. Unfavorable natural ventilation, which could contain or produce dangerous air contaminants or pollutants.
Manholes
Sewers
Tunnels
Ships’ holds
Wells
Tanks
Subcellars
Not intended for continuous employee occupancy.
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