00 Mechanical · NR-13
Compressor inspection reports and maintenance
Periodic inspection with a report issued by a licensed engineer. Without it, the equipment can be shut down by the labour inspectorate.
Why the report is mandatory
Periodic inspections with a report issued by a licensed engineer are compulsory under NR-13, the Brazilian standard for boilers, pressure vessels, piping and metallic storage tanks. Without the report, the equipment can be shut down immediately by the Ministry of Labour inspectorate.
Which vessels fall under NR-13
A pressure vessel is covered by the standard when it meets at least one of the following criteria:
- Any pressure vessel with a product P·V > 8, where P is the Maximum Allowable Working Pressure (MAWP) or maximum operating pressure, in kPa, and V is the internal geometric volume, in m³. Example: a compressed-air receiver operating at 8.5 bar (≈ 850 kPa) with a volume of 0.2 m³ (200 litres) gives P·V = 170. Since 170 > 8, it is fully covered.
- Vessels containing Class A fluids, regardless of the P·V value: flammable fluids, hydrogen, acetylene, combustible fluids at ≥ 200 °C or toxic fluids with an exposure limit ≤ 20 ppm.
- Mobile containers with P·V > 8 or containing Class A fluids.
Main exceptions
NR-13 itself (item 13.2.2) lists equipment that is not covered by the standard, even when operating under pressure:
| Exemption category | Equipment exempt from NR-13 |
|---|---|
| Small diameter | Pressure vessels with an internal diameter below 150 mm, whatever the fluid class. |
| Transportable / portable | Transportable gas bottles and cylinders, fire extinguishers and portable compressed-fluid reservoirs. |
| Other equipment | Hydraulic accumulators and blocks, corrugated-plate heat exchangers (gasketed or brazed), furnaces and coils, glass-fibre (GRP) vessels and vessels subject only to vacuum ≤ 5 kPa (with no Class A fluid). |
Fluid classes and risk groups
To determine the inspection frequency and the safety requirements of a covered vessel, the standard cross-references the fluid class with the risk potential group.
- Class A: flammable fluids, toxic fluids (≤ 20 ppm), hydrogen, acetylene and combustible fluids (≥ 200 °C).
- Class B: combustible fluids (< 200 °C) and toxic fluids (> 20 ppm).
- Class C: steam, compressed air and simple asphyxiant gases.
- Class D: other fluids not covered by classes A, B or C.
The risk potential groups are defined by the product P·V, with P (maximum operating pressure) in MPa and V in m³ (item 13.5.1.1.3):
- Group 1: P·V > 100
- Group 2: P·V < 100 and P·V > 30
- Group 3: P·V < 30 and P·V > 2.5
- Group 4: P·V < 2.5 and P·V > 1
- Group 5: P·V < 1
What the service guarantees
Operational efficiency, the integrity of compressed-air receivers, prevention of accidents from explosion or mechanical failure, and delivery of the pressure vessel record (prontuário) fully up to date.
Applicable standards: ABNT NBR 15417 (pressure vessels, in-service safety inspection) and NR-13 (Boilers, Pressure Vessels, Piping and Metallic Storage Tanks).
Need help categorising your equipment or checking specific documentation? We check it for you.
Questions about compressors and NR-13
What clients ask us most before ordering an inspection.
Does my compressor need an NR-13 report?
If the receiver has P·V > 8 (P in kPa, V in m³) or contains a Class A fluid, yes. An ordinary 200-litre compressor at 8.5 bar already gives P·V = 170.
What happens if I do not have the report?
The Ministry of Labour inspectorate can shut the equipment down immediately.
What is the pressure vessel record?
It is the equipment's documentation (the prontuário), which must be kept up to date. Delivering it updated is part of the service.
Do you help classify the equipment?
Yes. We check the categorisation and the specific documentation for you.
Request the report for your compressor
See full contact details on the home page.
Engineers of record Page maintained by LAMP Soluções, electrical, mechanical and solar engineering, based in Itabaiana, Sergipe, Brazil. The company's engineers of record: Hertes Garcia, electrical engineer, and Aline Garcia, mechanical engineer — both registered with CREA.