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Oil, gas and petrochemical process industries


    Confined Space-3

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    Talib Al_Munawri
    Director-General
    Director-General

    Posts : 337
    Join date : 2009-07-03
    Age : 30
    Location : Sultanate of Oman

    Confined Space-3

    Post by Talib Al_Munawri on Wed Oct 14, 2009 1:53 pm

    Confined Space



    There are certain space like tank, pits vessels main holes etc.
    when Workers are required to enter the confined spaces. These
    spaces are not congenial for life due to toxic contamination,
    Oxygen deficiency, excessive heat etc. In case if emergency,
    removal of effected workers from these spaces also poses persons
    entering the spaces for precaution also get over powered by this
    environment. Hence entry of workers in to any such space should
    be controlled by strict work permit to work system so that necessary
    testing of Environment and personal protection of workers may be
    ensured.


    Hazard Activities Entry into confined spaces





    Cleaning


    1. Pumping out/transfer, draining the contents.

    2. Isolation of vessel & equipment from all sources by
    disconnecting blinking etc.

    3. Purging the vessel with inert gases (N2), steam, water.

    4. Testing the vessel for toxic flammable gases.

    5. Testing the vessel for sufficient oxygen.

    6. Cleaning & washing the tank as per requirement of job.


    Ventilation


    It should be insure that proper ventilation of fresh air is
    maintained. If two opening at cross-position are available,
    blower can be used at one opening allowing air to escape from
    the other or it can be used exhaust fan.

    If one man hole is available through hose shall be supplied to
    the bottom of tank by service air line blow main operation.


    Electrical Isolation


    The Electrical depts. will ensure for electrical isolation.

    Entering into the vessel

    1.Suitable ladder should be used
    2.A man should be posted out site to keep watch
    on the man inside the vessel.


    TLV (There should limit value)

    TLV are published by USA & acceptable by other countries, as
    standards are known as permissible explosive Limit. In India it
    is called permissible level exposure.


    Type of TLV

    • TWA TLV
    • STEL TLV
    • CEILING TLV


    1.TWA TLV

    The time weighted average concentration for normal 8 hours work
    day without adverse effect.


    2. STEL TLV

    Short term exposure limit TLV is the most concentration to which the
    workers can be exposed for a period of up to 15 minutes continuously
    without adverse effect.


    3. CEILING TLV
    Four Dangers of confined Spaces


    1. Not enough oxygen exists because of oxidation or chemicals.
    Even if there is enough oxygen to breathe initially, you can use
    it up doing your work faster than you think.

    2. Fire and explosions can use oxygen quickly enough to prevent your
    escape and cause death within minutes. Chemicals, gases, and powders suspended in air (e.g. Coal duct and flour) can explode if exposed to
    flame, heat, sparks, or static electricity.

    3. Confined spaces are notorlous for trapping toxic and poisonous
    elements, many of which you cannot see or smell. Some can burn or
    smother you quickly, other have less obvious but long-lasting health
    effects.

    4. Confined spaces can intensify factors such as heat and noise and
    can result in related injuries.

    General Precautions

    1. Evaluate the workplace and designate all confined spaces.

    2. Test atmosphere to identify potential hazards.

    3. Post warning signs and entry barriers.

    4. Lockout/tag out all associated power systems and equipment

    5. Restrict entry into confined space with entry permits

    6. Provide equipment for testing, communicating, ventilating,
    and lighting’ for personal protection, and for access.

    7. Monitor confined spaces before and during work entry.8.
    Train authorized entrants, attendants and entry supervisors.9.
    Establish rescue procedures.

    8. Safety close confined spaces after work operations are concluded.


    Safety in Material Handling

    Accidents in material handling are 20% - 25% of the total accident
    in construction activities.
    Common types of injuries are sprain, fracture cut bruises and damage
    of veins due to crushing in the course of material handling.

    The major reasons for such accidents are:

    i) Lack of knowledge and skill.
    ii) Non use of PPE.
    iii) Lack of positive attitude towards safe practices.

      Current date/time is Tue Aug 22, 2017 9:42 pm