Page 19 - ELE1010

1.11 MYTHS ABOUT HAZARDOUS ATMOSPHERES
I can tell when there’s a problem in a vault or manhole.
WRONG. Most contaminants in a vault will have little or no odor. If they do have an odor, it will probably be slight compared to the general smells that are encountered in a subsurface structure.
If my instrument shows the permissible concentration of oxygen, there can’t be anything else in the structure, because it would make the oxygen level drop.
WRONG. The more dangerous contaminants that might be present can be harmful at very low concen- trations. These low concentrations will not cause an oxygen meter reading to change in any way.
The only time I need to worry about what’s in a structure is if there was a recent burnout or fire.
WRONG. A fire or burnout can cause higher levels of carbon monoxide, a dangerous gas. However, carbon monoxide or other gases could enter an underground structure through conduits from other
structures, through sewer lines, or through the soil or fill surrounding the structure.
If the oxygen level is low, I’ll notice and get out of the hole.
WRONG. While oxygen levels
slightly below the normal level of
21% may cause warning signs such as headache or fatigue, levels just a few percentage points lower will cause almost immediate loss of consciousness. Any loss of consciousness can result in a fall or contact with an energized component which by itself can be fatal.
I don’t need a testing instrument. I used to work in structures before testing instruments existed.
WRONG. While workers may be able to play the odds and not encounter problems, one bad decision can have tragic implications. Most fatalities and injuries in confined or enclosed spaces involved workers who have done the same job many times before without a probl
DON’T TAKE CHANCES...USE YOUR TEST INSTRUMENT!
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