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23. Regulations Concerning the Prevention of Explosions/Fires (Part 2)

1. The prevention of steam explosions due to melted high-temperature substances

a. Structure of buildings where melted high-temperature substances are handled

(a) Floor surface shall be so constructed as to prevent water from gathering.

(b) Roofs, walls and windows,etc shall be so constructed as to prevent rain water from entering.

b. Pits handleing melted high-temperature substances.

(a) The pits shall be so constructed as to prevent underground water from entering (except for those in which facilities are installed to discharge underground water).

(b) The pit shall have partitions or other facilities around them to preb\vent working water or rain watr from entering.

c. Water processing of high-temperature slag

The following measures shall be taken at places where high-temperature slag is processed with water or disposed of.

(a) Water can easily be discharged in such places.

(b) Signs shall be posted to indicate slags are disposed there.

d. Confirmation necessary for scrap metal to be thrown into metal melting furnace

Scrap metal shall be checked to confirm that no water, gunpowder, dangerous substances or airtight containers are included.

e. Prevention of burns, etc..

Workers shall wear the personal protective equipment when they handle a large amount of high-temperature materials.

2. Control of fires, etc.

  1. Use of fires, etc., prohibited

    Fires and machines that are likely to cause sparks, electric arcs or high temperatures leading to ignition source shall not be used at places where explosions or fires are likely to occur because of the existence of combustible dust (other than dangerous substances), gunpowder, a large amount of combustible materials or dangerous substances.

  2. Use of explosion-proof machines

    Explosion-proof machines with explosion-proof capabilities meeting the specific types of vapor, gas, or dust must be used at places where the danger of explosions may be expected due to the fact that flammable vapors, combustible gases or dust can reach certain concentrations even when steps such as ventilation or aeration are taken.

  3. Welding of pipes or containers

    Welding, melt-cutting or other operations involving the use of fire shall not be carried out on pipes, tanks, drums or other containers that may contain flammable oils (other than dangerous substances), combustible dust, or dangerous substances unless measures are taken to prevent explosions or fires.

  4. Prohibition of ventilation or aeration by oxygen

    Oxygen shall not be used for ventilation or aeration at places where ventilation or aeration is inadequate at times when welding, melt-cutting or heating of metals, dry grinding with whetstones, metal- or rock cutting with chisels or other operations that are likely to cause sparks are carried out.

3. Prevention of electrostatic accidents

  1. Use of clothing, etc., designed for preventing electrostatic accidents

    Workers shall be required to use clothing and shoes designed for preventing electrostatic charges at places where electrostatic accidents are likely to occur.

  2. Release of static electricity

    Static electricity shall be released from the following facilities by the use of ground wires, anti-electrostatic chemicals, moisturizing, or anti-electrostatic equipment:

    (a) Facilities used to inject dangerous materials into tank trucks or drums.

    (b) Facilities used to store dangerous materials including tank trucks or drums.

    (c) Facilities used to apply paints or adhesives containing flammable materials..

    (d) Industrial dryers used to dry dangerous materials or materials that are likely to generate dangerous materials.

    (e) Facilities used to transport combustible granules or powdery materials by spout or to sift such substances.

    (f) Other chemical facilities or their attached facilities.

4. Fire-extinguishing equipment, etc.

  1. Fire-extinguishing equipment, etc.

    Fire-extinguishing equipment shall be provided at places where buildings, chemical facilities, industrial dryers exist or where dangerous materials are handled.

  2. Fire-protection measures

    A distance necessary for fire protection shall be provided between a furnace, heating device, iron stack or other equipment that may cause a fire, and a building or other combustible objects. Otherwise such combustible objects shall be protected using insulating materials.

5. Industrial dryers

  1. Structure

    The outside and inside walls as well as the inside shelves of a an industrial dryers shall be made of non-combustible materials. Its upper structure shall be made of lightweight materials, and doors or pressure-release holes for explosions shall be installed.
    The structure also shall be capable of discharging to the outside any gases, vapors or dust that is generated as a result of drying operations if they are likely to explode or ignite.
    Peep windows, manholes, exhaust holes or other openings shall be installed at locations where they can be used for preventing the spread of fires. They shall be so structured that they can be immediately closed when necessary.
    Instruments for measuring or adjusting inside temperatures shall be installed.
    Direct fires shall not be used as a heat source.

  2. Appointment of operations chiefs

    Operation chiefs of industrial dryers shall be appointed for operations at facilities (with an internal volume of one cubic meter or more) to dry dangerous materials or materials likely to emit dangerous materials, or other industrial dryers that use fuel as heat source (ten kilograms/hour or more of solid fuels, ten liters/hour of liquid fuel and one cubic meter or more of gaseous fuels) or use electricity (limited to those with a rated power consumption of ten kilowatt or more). These operations chiefs are required to perform the following duties:

    (a) Providing instructions to workers concerning the relevant working methods and directly leading operations.

    (b) Taking the necessary measures when any inadequacy is found in industrial dryers or related facilities.

    (c) Undertaking inspections of the facility's internal temperatures, ventilating conditions, and dried material conditions, and immediately implementing the necessary measures if any abnormalities are detected.

    (d) Always keeping locations where drying facilities are installed in neat and clean condition and avoiding storing combustible materials nearby

  3. Periodic voluntary inspections

    Periodic voluntary inspections shall be conducted at least once a year and the results of inspections and repairs shall be kept for three years.

6. Manifold-type gas welding equipment

The following measures shall be taken for manifold-type gas welding equipment (equipment connecting ten or more combustible gas vessels with pipes, and equipment connecting nine or fewer combustible gas vessels with pipes if the internal volume of all vessels totals 400 liters or more for hydrogen or acetylene).

  1. Installation location, etc.

    (a) Equipment shall be located at places with a distance of five meters or more from fires.

    (b) Equipment other than movable units shall be installed in a dedicated room (gas equipment room).

    (c) Measures shall be taken to discharge any gases that may leak from any containers in the gas equipment room. The roof and ceiling of the gas equipment room shall be structured with light and non-combustible materials.

  2. Piping

    (a) Gaskets shall be used at portions connecting flanges, valves or cocks to tightly connect these parts.

    (b) Safety devices shall be installed in mains and branches. Two or more safety devices shall be installed in a blowpipe.

    (c) Copper or alloys containing 70 percent or more copper shall not be used for distribution pipes and/or attached equipment.

  3. Management

    (a) The name of the gas under use and its maximum storage volume shall be posted at easy-to-see locations.

    (b) A gas welding operations chief shall be present at places when gas containers are replaced.

    (c) Smoking, fires or activities that are likely to emit sparks shall be prohibited at places within five meters from the equipment and the notice of prohibition shall be posted.

    (d) The operational and inspection outlines for valves and cocks shall be posted at easy-to-see locations.
    (e) Gas and oxygen pipes shall be clearly marked.

    (f) Workers shall be required to use protective glasses and protective gloves.

  4. Operations chiefs of gas welding:

    (a) Determine operational methods and direct such operations.

    (b) Provide orders to workers to remove oil and dust adhering to gas vessels caps or pipe connecting points;

    (c) Require workers to inspect gas leakage after vessels replacements Inspections shall be made safely by using soapy water;

    (d) Attend gas vessels replacements;

    (e) Inspect hoses, blowpipes, hose bands and other devices before starting operations and carrying out the necessary repairs;

    (f) CInspect safety devices at least once every day; and

    (g) Monitor the use of protective glasses and protective gloves by workers.

  5. Regular voluntary inspections

    Regular voluntary inspections shall be conducted at least once every year on manifold-type gas welding equipment and the results of such inspections and repairs shall be kept for three years.
    (Note: Although there also are regulations concerning acetylene welding equipment (including acetylene generators), these regulations are omitted here as they are rarely used now.).

(Regulations concerning Prevention of accidents in cargo handling operations will be discussed in the next session)