Ordinance on Safety and Health of Work under High Pressure

Chapter II.  Facilities

Section 1.  Facilities for Work in Compressed Air

(Cubic Space of Work Chamber)

Article 2.  When the employer has workers engage in work in compressed air in a work chamber, the cubic capacity per worker engaged in work in compressed air in the said work chamber shall be 4 m³ or more.

(Floor Area and Cubic Space of Man-Locks)

Article 3.  The employer shall provide man-locks with a floor area and cubic capacity of at least 0.3 m² and 0.6 m³ respectively per compressed air worker who has to be treated with compression or decompression in the said man-lock.

(Piping, etc., of Air Pipelines)

Article 4.  In terms of air pipelines for supplying air to the work chamber or the man-lock of caissons or diving bells, the employer shall provide the said pipelines in such a manner that they lead to the said work chamber or the man-lock without passing through a shaft.

2.  In terms of an air pipeline to supply air to the said work chamber, the employer shall provide the pipeline with a check valve at a site near the work chamber.

(Air Cleaning Equipment)

Article 5.  The employer shall provide devices to clean the air which is supplied to the work chamber and the man-lock at a portion of air pipeline between the air compressor and work chamber or man-lock.

(Exhaust Pipelines)

Article 6.  The employer shall provide each work chamber or man-lock with exhaust pipelines exclusively used for the said work chamber or the said man-lock.

2.  The exhaust pipeline for the purpose of decompression of the compressed air workers in the man-lock of caissons or diving bells shall be 53 mm or less in inside diameter.

(Pressure Gauges)

Article 7.  When the employer provides places by which to operate or adjust valves or cocks thereby to regulate the feeding of air to the said work chamber outside the caissons, diving bells, compressed shields, etc., he shall provide these places with a pressure gauge which indicates gauge pressure (hereinafter called "pressure") which shows pressure levels within the chamber.

2.  When the employer provides the said places inside the said caissons, diving bells, compressed shields, etc., the employer shall have the worker who engages in the work thereby to operate or adjust valves, or cocks thereby to regulate the feeding of air to the said work chamber carry a portable pressure gauge.

3.  When the employer provides places in which to operate valves or cocks thereby to regulate the feeding of air or exhausting of air for the purpose of applying compression or decompression to the compressed air workers outside the man-lock the employer shall provide the said places with a pressure gauge which indicates the pressure levels within the man-lock.

4.  When the employer provides the said places set forth in the preceding paragraphs inside of the man-lock, the employer shall have the worker who engages in the work thereby to operate the valves or cocks by which to regulate the feeding of air or exhausting of air of the man-lock carry a portable pressure gauge.

5. The types of pressure gauges, set forth in the preceding four paragraphs, shall be of an accuracy such that one gradation on its scale represents 0.02 MPa or less.

(Automatic Warning Devices for Abnormal Temperature Levels)

Article 7-2.  In case there might occur an abnormal increase in the temperature of the air discharged from the air compressor thereby to send air to the working chamber or to the man-lock or the air which has passed through cooling devices attached to the said air compressor, , the employer shall install an automatic warning device thereby to quickly inform the workers who are engaging in operating the air compressor or other persons concerned of the abnormal increase in the temperature.

(Peepholes, etc.)

Article 7-3.  The employer shall assume measures by which to make it possible to confirm or understand the conditions inside of the man-lock from outside of the said man-lock, comprising a peephole, etc., thereby to enable the person concerned to observe the inside of the man-lock.

(Evacuation Devices, etc.)

Article 7-4.  When the employer has workers engage in work in compressed air, the employer shall provide devices necessary to make it possible to have the compressed air workers evacuated or be rescued in case of emergency, comprised of respiratory protective equipment or fiber ropes, etc.

Section 2.  Facilities for Diving Operations

(Air Reservoir)

Article 8.  When the employer feeds air to workers engaged in diving operations (hereinafter called diving workers) using an air compressor, the employer shall provide one air reservoir thereby to regulate the volume of fed air and one more air reservoir therein to store the air necessary in case of an accident (hereinafter called the "emergency air reservoir") per diving worker being fed with air by the said air compressor.

2.  The emergency air reservoir shall comply with the requirements given in the following:

(1)  The infra-air-reservoir pressure levels shall be regularly 1.5 times as high as the pressure levels at the maximum diving depth or more.

(2)  The inside volume of the air reservoir shall of a value equal to that obtained by the formula of (a) or (b), or higher.

a  When the employer has the diving workers use pressure regulator.

b  In the case other than described in preceding paragraph a.

3.  When the air reservoir thereby to regulate the air set forth in paragraph 1 complies with the requirements as provided by the respective items of the preceding paragraph, the said emergency air reservoir can be omitted in spite of the provisions of paragraph 1.

(Air Cleaning Device and Flow Meter)

Article 9.  When the employer feeds air to the diving workers using the air compressor, the employer shall provide devices thereby to clean the air fed to the said diving workers and also flow meters thereby to measure the flow volume of the air fed to the said diving workers.