How Can You Identify Confined Spaces ?

   How Can You Identify Confined Spaces ?

If a Workplace is

—  Having limited number of entry and exit

—  Having unfavorable ventilation

—  Not designed for continuous worker occupancy

—  In general, unlimited hazards with limited entry and exits.

“Then it is said to be a confined space.”

Limited Number Of Entry & Exit

·        Some times as small as 18 inches in diameter.

·        Small openings may make it difficult to enter with equipment

·        Rescue will become more difficult.

·        In some cases openings may be too large but entry & exit may be very difficult.

·         Excavations, Open top storage tanks etc.,

·        It requires Ladder, Hoist (or) any other lifting equipment's for entry & exit

Unfavorable Ventilation

·        Air may not move in (or) move out because of its design.

·        Atmosphere inside the confined space  can be very different from outside.

·        Deadly gases may present inside (Particularly if the space used for storage of chemical substances)

·        Some times Oxygen may be insufficient – Lack of Oxygen (Suffocation/Asphyxiation)

·        Some times Oxygen may be more – Enrichment of Oxygen (Increases the chances of fire & explosion)

Not Designed For Continuous Worker Occupancy

·        Most confined spaces are not designed for workers to enter and work on a routine basis.

·        They are designed to store the chemicals or any other products.

·        Occasional entry for workers is necessary for inspection, maintenance, repair and cleanup.

·        It is difficult & dangerous due to chemical & physical hazards within the space.

                  Hazards in Confined Space

·        Oxygen Deficient Atmosphere

·        Flammable Atmosphere

·        Toxic Atmosphere

Oxygen Deficient Atmosphere

Atmospheric air is having 21% of Oxygen.

·        If any atmosphere has less than 19.5% of Oxygen then it is said to be Oxygen deficient.

·        Oxygen in confined space can decrease because of the work being done (or) it can be decreased by chemical process.

·        Oxygen level can also be decreased if it is displaced by another gas such as Nitrogen , Carbon Di Oxide.(Which will result in death)

·          No personnel's are allowed to enter these places without    wearing an approved SCBA (Self Contained Breathing Apparatus).

Flammable Atmosphere

·        2 things make an atmosphere flammable

1)   Oxygen in the air A flammable gas 2) Vapor (or) Dust in proper mixture

·        If a source of ignition is introduced into the flammable atmosphere, an explosion will occur.

·        An Oxygen enriched atmosphere (above 21%) will cause flammable materials to burn violently when ignited.

Therefore never use pure oxygen to ventilate a confined space.

Toxic Atmosphere

Toxic substances in a confined space     can come from the following;

·        Product stored in the space - Removal of sludge from storage vessel

·        Work being performed in a space - Welding, Cutting, Grinding

·        Areas adjacent to the confined space

Hydrogen Sulfide

·        It is a colorless, very poisonous, flammable gas with the characteristic foul odor of rotten eggs.

·        Hydrogen sulfide is a highly toxic and flammable gas

·        Being heavier than air, it tends to accumulate at the bottom of poorly ventilated spaces.

·        Although very pungent at first, it quickly deadens the sense of smell, so potential victims may be unaware of its presence until it is too late.

Atmosphere Testing

·        It is important to understand that some gases (or) vapors are heavier than air, which may settle at the bottom of a confined space.

·        Also some gases are lighter than air, which may present around the top of the confined space.

·        And some gases are same as air, which may present anywhere.

·        If testing reveals Oxygen deficiency (or) the presence of toxic gases, the space must be ventilated and retested before entry.

·        If ventilation is not possible and entry is necessary (Ex: Rescue) workers must have proper respiratory protection.

·        Never trust your sense to determine that the confined space is safe!!!

·        You CANNOT see/smell the toxic gases & you CANNOT determine the level of Oxygen.

Ventilation

·        Ventilation by a blower may be necessary to remove harmful gases from confined space.

·        Common method of ventilation requires   a large hose, one end attached to a hose and other end lowered into manhole.

·        The hose must run up to the bottom of  the confined space  for effective ventilation.

·        The air intake of the blower must be placed in a fresh air area only.

·        Ventilation must be continuous, because the hazardous atmosphere may reform again if the ventilation is stopped.

·        The ventilation must be continuous and it should not be stopped by any means.

·        In the mean time the ventilation hose must not affect the entry & exit of workers in to the confined  space.

Respiratory Devices

·        Do not use Air Purifying devices in confined spaces because it will further reduce the level of inhaling oxygen.

·        Use only Air Supply devices

Winch Tripod

Workers those who are entering into the confined space must be connected with winch tripod kept near the entrance.

Standby/Rescue

·        A standby person should be assigned to remain on the outside of confined space & be in constant contact with the workers inside.

·        The standby person should not have any other duties, he should be aware of the person to be contacted in case of emergency.

·        Standby person should not enter the confined space until the help arrives.

·        After the arrival, he should enter with proper protective equipment, life lines, respirators etc.

Rescue Training

·        Over 50% of workers die in confined spaces while they are attempting to rescue other workers.

·        Rescuers must be trained in appropriate emergency procedures & usage of appropriate equipment s.

·        Steps for safe rescue  must be included in confined space entry procedures.

·        Mock drill should be frequently conducted.