Confined Spaces

Confined spaces present an added element of danger to the work place. We define a confined space with three criteria: (1) enclosures having limited means of entry and exit such as storage tanks, tank cars, bins, boilers, and other tank-like compartments usually with only a manhole for entry; (2) open-topped spaces not subject to good natural ventilation, more than four (4) feet in depth such as pits, vaults, and vessels; and (3) underground structures such as septic tanks, sewers, utility tunnels, and pipelines.
If work is to be performed in an area such as this, the following guidelines must be followed:

1. Do not enter if work can be done on top or outside.

2. Blank-off inlet and outlet lines; lock all valves in closed position and all switches "off."

3. Remove manhole covers or entry doors; avoid breathing vapors when removing covers; ventilate space.

4. Purge by blowing air, steam, or both into space to be entered, to exhaust the confined space. Do not enter space until space is properly tested and certified as safe.

5. Test for: a. Combustible Gas b. Oxygen deficient atmosphere (carbon dioxide) c. Carbon monoxide d. Other suspected toxic gases (Exposure may cause inability to smell; do not rely on your sense of smell.)
6. Always put on harness and life line (two men "on top") when going into a manhole, sewer or inadequately ventilated confined space. Continue to test air when entering any confined space. Electrical equipment must be explosion proof if flammable mixtures could be present. Guard stationed outside confined space must not enter in rescue attempt until other help has been called.
7. If the atmosphere is potentially dangerous or oxygen deficient, in addition to the harness and life line, wear a NIOSH or U.S. Bureau of Mines approved air line or self-contained breathing apparatus. (See warning below.)
8. Always recheck air quality each day after breaks or after space has unoccupied before entering a manhole, sewer, conduit or other confined space (steps 1 through 7 above) and keep records of test results from 5 above made prior to all entries, and of all persons entering.
WARNING: Some vapors or gases, such as hydrogen cyanide, can be absorbed through the skin and require complete body protection.
REMEMBER: Continue to mechanically ventilate the space at all times while inside.

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