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Notification No.196 of the Ministry of Health, Labour and Welfare
April 30, 2003

In Japanese

Part 1. Construction Code for First Class Pressure Vessels

Chapter 4. Fittings

Article 64. Safety Valves and Alternative Safety Devices
1. Any First Class pressure vessel shall be equipped with a safety valve or an alternative safety device for each of those parts which are subject to exposure to different levels of pressure, to ensure that the internal pressure working on any of such parts will not rise above the maximum allowable working pressure. However, this provision does not apply to those parts of a First Class pressure vessel (other than a reactor) which are connected with a boiler or some other source of pressure and of which the maximum allowable working pressure is not lower than that of such pressure source.
2. Safety valves for First Class pressure vessels shall be attached to those parts of the vessel itself or of its tubing which are easily accessible for checkup purposes, and shall be installed in such a manner that their stems will be upright.
3. Safety valves for those First Class pressure vessels in which flammable or toxic vapours may be generated shall be hermetically sealed or so configured that they can burn, absorb or otherwise dispose of such vapours safely.

Article 65. Name Plates
1. Any lift-type safety valve having a lift not less than 1/15 the diameter of its seat aperture or any full-bore safety valve (referred to as "lift-type safety valve" in the following paragraph) provided for First Class pressure vessels with a maximum allowable working pressure of over 0.1 MPa shall conform to the material and structural specifications set forth in JIS B 8210 (Steam Boilers and Pressure Vessels -- Spring Loaded Safety Valves), or have equivalent or superior mechanical properties.
2. A name plate showing the content specified in the following items shall be attached to a conspicuous part of its housing.
(1) Name of the manufacturer or trade mark;
(2) Nominal diameter;
(3) Specified pressure (MPa); and
(4) Discharge capacity (kg/h).

Article 66. Exceptive Case of Two or More First Class Pressure Vessels Installed Close Together
If two or more adjacent First Class pressure vessels are connected with one another and are operated together in such configuration and if there is no valve installed between any two of them, the First Class pressure vessels thus connected and operated together may be deemed one integrated installation, and as such, the provisions in Chapter 4 (except Articles 67 and 69) shall apply to these pressure vessels.

Article 67. Quick Opening-Closing Devices for the Cover
Quick opening-closing devices for the cover plate of First Class pressure vessels shall be so designed that the cover plate can be opened only when the residual pressure in the vessel is equal to the pressure level of its environment.

Article 68. Pressure Gauges
Any First Class pressure vessel shall be equipped with a pressure gauge in accordance with the following items.
(1) It shall be clearly shown whether related valves or cocks are open or closed.
(2) The highest reading on the scale plate of such pressure gauge shall be in a range not lower than 1.5 times, but not higher than 3 times, the specified maximum allowable working pressure.

Article 69. Thermometers
Any First Class pressure vessel shall be equipped with a thermometer to indicate the temperature of the fluid contained in it unless there is no probability that the temperature of any material of such pressure vessel will, while in service, ever exceed the permissible level determined from the maximum allowable working temperature for the vessel.

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Supplementary Provisions