Air compressor maintenance safety

⚠What laws and standards require

• Order for Enforcement of the Industrial Safety and Health Act, Article 1, item 7 (definition of Class 2 pressure vessel)

  A vessel holding gas at a gauge pressure of 0.2 MPa or more, with an internal volume of 0.04 m³ or more, or with a shell inside diameter of 200 mm or more and a length of 1,000 mm or more (excluding Class 1 pressure vessels)

  This covers many shop air tanks and the tanks attached to compressors. No installation notification is required, but type inspection, periodic voluntary inspection, and measures for the safety valve and pressure gauge are^[1][2][3]

• Boiler and Pressure Vessel Safety Regulations, Article 84 (type inspection)

  Anyone who manufactures or imports a Class 2 pressure vessel must undergo the individual inspection under Article 44 of the Industrial Safety and Health Act

  Inspection is also required when a company makes a vessel and uses it itself (MHLW case). The Class 2 pressure vessel specification sheet is proof of inspection, so keep it safe (ANEST IWATA)^[4][3][5]

• Boiler and Pressure Vessel Safety Regulations, Article 88 (periodic voluntary inspection) and Article 89 (repairs, etc.)

  At least once within every year after the start of use, carry out a voluntary inspection for damage to the body, wear of the cover tightening bolts, and damage to pipes and valves, and keep the results for 3 years. Repair anything abnormal

  It is not a specified voluntary inspection, so the business operator may carry it out itself. A sample record form is often included in the instruction manual (Meiji Machine)^[4][2][6]

• Boiler and Pressure Vessel Safety Regulations, Article 86 (adjustment of safety valves) and Article 87 (protection of pressure gauges)

  Adjust the safety valve to operate at or below the maximum allowable working pressure (if there are two or more, the others may be set up to 3 % above). Take measures to keep the pressure gauge from freezing and from reaching 80 °C or more, and put an easy-to-see marking at the maximum allowable working pressure on the dial

  The safety valve is the last safety device protecting the vessel. Never remove it or raise its set pressure (countermeasure from the MHLW case)^[4][6][3][7]

• High Pressure Gas Safety Act, Article 2; Order for Enforcement of the High Pressure Gas Safety Act, Article 2, paragraph 5, item 1

  Compressed gas that reaches 1 MPa or more at normal operating temperature is high-pressure gas. However, compressed air inside a compression system (excluding air separation plants) that is 5 MPa or less at 35 °C is exempt

  Most factory air compressors fall under this exemption, but if the discharge pressure is 1 MPa or more, or if you install a booster, check with the manufacturer how it is treated. Producers of high-pressure gas are obliged to maintain their facilities to the technical standards (JSIM)^[8][9][2]

• Noise Regulation Act Enforcement Order, Appended Table 1, item 2; Vibration Regulation Act Enforcement Order, Appended Table 1, item 2; Article 6 of both Acts

  Air compressors with a prime mover rated output of 7.5 kW or more are designated facilities under the Noise Regulation Act and the Vibration Regulation Act (excluding low-noise and low-vibration types designated by the Minister of the Environment). When installing one in a designated area, notify the mayor of the municipality at least 30 days before construction starts

  Noise and vibration at the site boundary must be kept at or below the local limits. The requirements differ by prefecture. Compressors with type approval as low-vibration types are outside the scope of the Vibration Regulation Act (JSIM). ANEST IWATA's explanation gives the place to notify as “the prefectural governor via the municipal pollution-control desk”, but the current Article 6 on e-Gov calls for notification to the mayor of the municipality^{[10][11][12][13][2][3]}

• Act on Rational Use and Appropriate Management of Fluorocarbons (Fluorocarbon Emissions Control Act)

  Refrigerated dryers and units with a built-in refrigerated dryer are Class I specified products. While in use, perform a simple inspection at least once every 3 months and keep records; at disposal, ask a registered company to recover the fluorocarbons

  If a leak is found, repair it promptly, and do not top up before repairing. Where the refrigeration unit's output is 7.5 kW or more, periodic inspection is also required (Atlas Copco). The articles and notices were not checked on e-Gov (based on explanations from the industry association and manufacturers)^[2][3][14]

• Water Pollution Prevention Act (discharge of oil-containing condensate)

  The condensate from oil-lubricated units contains oil, so do not drain it as is. Separate the oil with a treatment unit, or contract it out as industrial waste

  Discharge standards differ by region, so check with the pollution-control desk of your city, ward, or town office (ANEST IWATA). The standard value (ANEST IWATA cites an oil content of 5 mg/L or less) was not checked on e-Gov^[15][16]

• Judgment Standards for Business Operators on the Rational Use of Energy in Factories and Other Workplaces (METI Public Notice)

  For fluid machinery such as compressors, review the pressure and flow rate at the point of use, and set management standards for the number of units and rotation speed according to load. Prevent leakage and reduce piping resistance through regular maintenance and inspection. For uses that need only low pressure, use a low-pressure blower or fan instead of reducing the pressure

  Even if you are not a designated business operator under the Energy Conservation Act, this is the basis for thinking about energy saving in air systems. Its three pillars are reducing consumption, reducing leaks, and lowering pressure (Energy Conservation Center). Compressors are said to account for roughly 10–30 % of a whole factory's electricity (JSIM and AIRMAN: 20–30 %; J-Net21: 10–30 %)^{[17][18][19][20]}

• Manufacturers' instruction manuals and industry association documents (shutting down and releasing residual pressure before inspection)

  Before cleaning or inspection, turn off the main power, open an air valve or drain valve to bring the tank pressure to zero, and put up a “maintenance in progress” sign

  If you remove a pressurized part such as the pressure gauge while pressure remains, parts can fly off. There is also a risk of entanglement in rotating parts and electric shock (Meiji Machine). Electrical work is done by people with specialized knowledge, such as chief electrical engineers and licensed electricians (JSIM)^[6][21][16]

The legal provisions are summarized in Kezuriba's own words. Check the exact wording against the original text in e-Gov Law Search.