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32. Safety of boilers and pressure vessels
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Ensuring the safety of boilers and pressure vessels has such a long history that the field can be referred to as a pioneer of safety in Japan. Detailed regulations are stipulated, with the participation of the national government, covering the stages from manufacture to usage. (See 4. Ordinances on Machines, Etc.)
In recent years, in view of the international situation, etc., some regulations have eased.
(The Industrial Safety and Health Law, and the Ordinance on Safety of Boilers and Pressure Vessels)
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1. Permission for manufacture, national inspection, etc.
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| a. |
Permission for manufacture (Law, Article 37, and Ordinance, Articles 3
and 49)
The manufacture of boilers and pressure vessels is subject to permission
by the Director General of the Prefectural Labour Bureau concerned.
| (a) |
Boilers and pressure vessels in need of permission
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Boilers (excluding small size boilers, and boilers to which the Ship Safety Law and the Electric Utility Industry Law are applied)
(Note) Examples of small size boilers:
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A steam boiler used at a gauge pressure of 0.1 megapascal or less, and
with a heating surface area of 1 square meter or less, or with a cylinder
inner diameter of 300 mm or less, and with a length of 600 mm or less
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A hot water boiler used at a gauge pressure of 0.1 megapascal or less,
and with a heating surface area of 8 square meters or less
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A once-through boiler used at a gauge pressure of 1 megapascal or less,
and with a heating surface area of 10 square meters or less
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Class-1 pressure vessels (excluding small size pressure vessels, and pressure vessels to which the Ship Safety Law, the Electric Utility Industry Law, the High Pressure Gas Safety Law, the Gas Utility Industry Law, and the Liquefied Gas Law are applied)
(Note) Examples of small size pressure vessels:
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A pressure vessel used at a gauge pressure of 0.1 megapascal or less, and
with an internal cubic volume of 0.2 square meter or less, and with a length
of 1,000 mm or less
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A pressure vessel of 0.02 or less as the product obtained by multiplying
the maximum service gauge pressure expressed in megapascals by the inner
cubic volume expressed in cubic meters
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| (b) |
Units (types) considered for permission
The types of boilers and pressure vessels as units considered for permission
for manufacture are as follows:
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Boilers
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Water tube boiler
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Cylindrical boiler (vertical boiler, flue tube boiler, fire tube boiler or locomotive type boiler)
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Hot water boiler
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Cast iron boiler
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Pressure vessels
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Cylindrical class-1 pressure vessel
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Rectangular class-1 pressure vessel
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Jacketed class-1 pressure vessel
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Multitubular class-1 pressure vessel (including U-shaped tube type and coil type)
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Spiral type class-1 pressure vessel
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| (c) |
Documents necessary for application for permission
When an application for permission for manufacture is filed, the following
documents are necessary:
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Strength calculation statement
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Types, capacities and number of equipment used for manufacture and inspection
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Outline of personal histry of the responsible person for workmanship
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Qualifications and number of workers those who are to be engaged in actual
fabricating work if class-1 pressure vessels
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Welding procedure test results if welding is used for manufacture
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| (d) |
Outline of permission criterion (1972 Notification No. 75)
The permission criterion for manufacture is as follows:
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The construction should conform to the Construction Code
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The equipment used for manufacture and inspection, workers who are to be
engaged in actual fabricating work and the responsible person for workmanship
should satisfy specific requirements |
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| b. |
Inspection at the time of manufacture, etc. (Law, Article 38, Ordinance,
Articles 5 to 9, 41 to 43, 51 to 55 and 76 to 78)
| (a) |
Structure inspection and welding inspection (Director General of the Prefectural
Labour Bureau concerned, etc.)
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The manufacturer of a boiler or class-1 pressure vessel must undergo the
structure inspection at the time of manufacture, by the authorized agency
for inspection designated by the Director General of the Prefectural Labour
Bureau concerned or the Minister of Health, Labour and Welfare. (The inspection
of a waste heat boiler may be excluded.) |
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A boiler or pressure vessel produced using welding must undergo the welding
inspection by the Director General of the Prefectural Labour Bureau concerned
or by the authorized agency for inspection at the time of manufacture,
prior to the structure inspection.
A licensed special-class boiler welder must carry out the welding (a licensed ordinary-class boiler welder may also carry out the welding if the weld zone is 25 mm or less, or if a nozzle neck, flange or the like is being welded).
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The boiler or pressure vessel that has passed the structure inspection
will be impressed, and a structure inspection passing seal will be affixed
to the specification. Furthermore, an inspection certificate will be issued. |
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| (b) |
Inspection at the time of importation and pre-installation (Director General of the Prefectural Labour Bureau concerned, etc.)
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An imported boiler or pressure vessel manufactured in a foreign country
must also undergo the structure inspection as described above, in principle. |
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A boiler or pressure vessel that is not installed for 1 year or more after
manufacture (2 years or more as a result of deregulation, if it is stored
in a good condition), or a boiler or pressure vessel that is installed
or used after discontinuation, must undergo the pre-installation inspection
by the Director General of the Prefectural Labour Bureau concerned or by
the authorized agency for inspection at the time of manufacture. |
| • |
A boiler or pressure vessel that has passed the pre-installation inspection
will be impressed, and a passing seal will be affixed to the specification.
Furthermore, an inspection certificate will be issued.
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| c. |
Inspection at the time of installation and use
| (a) |
Installation notification and completion inspection (Law, Articles 38 and
88, and Ordinance, Articles 10, 11, 14, 56, 59, 90-2 and 91)
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An employer who is going to install a boiler or class-1 pressure vessel
must submit an installation notification to the Chief of the competent
Labour Standards Inspection Office concerned, and undergo the completion
inspection.
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A person who is going to install a mobile boiler or small size boiler must
submit an installation report to the Chief of the competent Labour Standards
Inspection Office concerned.
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| (b) |
Regular inspection (Law, Article 41; Ordinance, Articles 37 to 40 and 72
to 75)
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The validity term of an inspection certificate of a boiler or class-1 pressure
vessel is one year, and a person who is going to have it renewed must undergo
and pass the regular inspection by the Chief of the competent Labour Standards
Inspection Office concerned or by an authorized agency for regular inspection.
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The validity term is less than one year, or more than one year to within
two years, depending on the result of inspection. |
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| (c) |
Alteration inspection (Ordinance, Articles 42, 43, 77 and 78)
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When the shell, dome, flue tube, fire box, end plate, crown plate, tube
plate, header, stay, attached equipment, burning apparatus, or installation
foundation, etc. of a boiler is going to be altered, it must undergo an
alteration inspection by the Chief of the competent Labour Standards Inspection
Office concerned. (This will not apply when the Chief of the competent
Labour Standards Inspection Office considers it unnecessary.) |
| • |
When the shell, end plate, bottom plate, tube plate, cover plate, or stay
of a class-1 pressure vessel is going to be altered, it must undergo an
alteration inspection by the Chief of the competent Labour Standards Inspection
Office concerned. (This will not apply when the Chief of the competent
Labour Standards Inspection Office considers it unnecessary.)
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For an alteration that has passed inspection, the inspection certificate
will be endorsed in the altered portion.
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| (d) |
Inspection for resumption of use (Ordinance, Articles 45 to 47 and 80 to
82)
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In the case where the use of a boiler or class-1 pressure vessel is suspended,
it must be reported to the Chief of the competent Labour Standards Inspection
Office concerned. |
| • |
In the case where the boiler or class-1 pressure vessel, the use of which
is suspended, is going to be reused, it must undergo an inspection for
resumption of use by the Chief of the competent Labour Standards Inspection
Office concerned. |
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| d. |
Examination (Law, Article 44; Ordinance, Article 84) |
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A class-2 pressure vessel that has been manufactured or imported must undergo
an examination by the Minister of Health, Labour and Welfare, the Director
General of the Prefectural Labour Bureau concerned, or an individual examination
agency. |
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2. Restriction of use (Law, Articles 37, 40 and 42; Ordinance, Articles
26, 64 and 90-2)
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A boiler, etc., for which no inspection certificate is issued, cannot be
used. |
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When a boiler, etc. is transferred or lent, the inspection certificate
must be attached. |
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A class-2 pressure vessel, small size boiler, or small size pressure vessel,
which is not examined by the authorities, cannot be transferred, lent,
nor installed. |
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A boiler or class-1 pressure vessel that does not conform to the Construction
Code cannot be used. |
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3. Limitation of job placement (Law, Article 61; Order Article 20; Ordinance,
Articles 16, 23, 24 and 25)
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When a boiler is installed, an operation chief of boiler installation work
must be appointed, and the installation work must be carried out under
his/her command. |
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No persons other than those having a license for special-class boiler operator,
first class boiler operator, or second class boiler operator can carry
out boiler operation work. (This does not apply to small size boilers.)
A person who has completed the skill-training course for the operation
of boilers can operate the following boilers: |
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A steam boiler with a shell inner diameter of 750 mm or less, and a shell
length of 1,300 or less
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A steam boiler with a heating surface area of 3 square meters or less
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hot water boiler with a heating surface area of 14 square meters or less
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A once-through boiler with a heating surface area of 30 square meters or less
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It is necessary to appoint a operation chief of boiler, from the boiler
operators, who is qualified for the heating surface area, etc. of the boiler.
(A special-class boiler operator for a boiler with an overall heating surface
area of 500 square meters.)
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When letting workers operate small size boilers, employers should specially
educate them beforehand.
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4. Periodical voluntary inspection, etc. (Law, Article 45; Ordinance, Articles
32, 33, 67, 84 and 94)
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The employer must voluntarily inspect boilers and class-1 pressure vessels
at least once a month.
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The employer must voluntarily inspect class-2 pressure vessels, small size
boilers, and size small size pressure vessels at least once a year.
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When igniting a boiler, it is necessary to check the damper and to internally
ventilate the combustion chamber and the flue.
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(The next article in this series covers the safety of cranes, etc.) |
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