Compressors are products subject to a noise limit under Directive 2000/14/EC, which regulates the noise emission of equipment for use outdoors. For these products the CE marking alone is not enough; the noise label, the EC declaration of conformity, the notified body certificate and the noise test report must all be in place. This article explains in detail how compressors stand under 2000/14/EC: the limit values, the measurement method, the conformity assessment procedures and the machinery safety side. It also includes a calculator with which you can work out the limit value by entering the engine power of your compressor.
Which Compressors Are Covered by 2000/14/EC?
Under the Outdoor Noise Directive 2000/14/EC, compressors with a net installed power below 350 kW are subject to a noise limit. According to the Directive, a compressor is any machine that compresses air, gases or vapours to a pressure higher than the inlet pressure; it comprises the bare compressor itself, the prime mover and any component or device supplied which is necessary for safe operation.
- Diesel-driven, trailer-mounted (portable) site compressors,
- Electrically driven screw and reciprocating compressors designed for use outdoors,
- Portable, wheeled compressors.
Fans (low-pressure devices providing air circulation) and vacuum pumps are excluded. Whether compressors designed only for stationary indoor use are in scope is assessed on the basis of the intended use of the product and the manufacturer’s declaration.
Noise Limit Values for Compressors
| Net installed power P (kW) | Permissible LWA (dB / 1 pW) |
|---|---|
| P ≤ 15 | 97 |
| 15 < P < 350 | 95 + 2 lg P |
“lg” is the base-10 logarithm. The calculated value is rounded to the nearest whole number (down if less than 0.5, up if 0.5 or more).
Compressor Noise Limit Calculator
Enter the engine power of your compressor in kW or HP. If you also enter the guaranteed value on your label, it is compared with the limit.
For information only. P: net installed power of the engine driving the compressor (kW). The limit value is rounded to the nearest whole number (0.5 and above rounds up).
Example Limit Values for Common Engine Powers
| P (kW) | ≈ HP | Calculated | Limit LWA (dB) |
|---|---|---|---|
| 4 | 5 | 97.00 | 97 |
| 7.5 | 10 | 97.00 | 97 |
| 11 | 15 | 97.00 | 97 |
| 15 | 20 | 97.00 | 97 |
| 22 | 30 | 97.68 | 98 |
| 37 | 50 | 98.14 | 98 |
| 55 | 74 | 98.48 | 98 |
| 75 | 101 | 98.75 | 99 |
| 110 | 148 | 99.08 | 99 |
| 160 | 215 | 99.41 | 99 |
| 250 | 335 | 99.80 | 100 |
| 315 | 422 | 100.00 | 100 |
The limit value stays within the range 97–100 dB. When the power doubles, the limit rises by only about 0.6 dB; for high-power compressors, the design of the enclosure insulation, the fan and the exhaust silencer is therefore critical.
How Is Compressor Noise Measured?
The measurement is carried out according to the compressor test code in Annex III, Part B of 2000/14/EC, using the basic standard EN ISO 3744 (the compressor-specific noise test code is also consistent with ISO 2151):
- Set-up: The compressor is placed on a reflecting (hard) surface; trailer-mounted compressors are measured on their own wheels.
- Measurement surface: A hemisphere with 6 microphone positions according to Annex III, Part A, or a parallelepiped with a measurement distance d = 1 m according to EN ISO 3744.
- Operating conditions: The compressor must be warmed up and in a stable condition as in continuous operation; it is run at full load or under a condition that is reproducible and representative of the noisiest operation.
- Result: The A-weighted sound power level (LWA) is calculated from the measured sound pressure levels; background noise and environmental corrections are applied.
Noise Conformity Assessment Procedures: Annex VI, Annex VII and Annex VIII
Compressors with a net installed power below 350 kW are listed in Article 12 of 2000/14/EC, i.e. among the equipment subject to noise limits. It is therefore not sufficient for the manufacturer to declare conformity through its own internal control of production (Annex V) alone; a notified body must be involved. The manufacturer chooses one of the following three procedures:
| Procedure | How does it work? | Who is it suitable for? |
|---|---|---|
| Annex VI – Internal control of production with assessment of technical documentation and periodical checking | The notified body examines the manufacturer’s technical documentation and measurement results, has the measurements repeated where necessary and issues a certificate of conformity. It then verifies through periodical checks that series production conforms to that certificate. | Manufacturers in series production who make particular models on a continuous basis. |
| Annex VII – Unit verification | The notified body examines each individual product (unit) to be placed on the market, carries out the noise measurement and issues a certificate of conformity for that unit. | Made-to-order, one-off or small-quantity production; individually imported products. |
| Annex VIII – Full quality assurance | The notified body assesses and approves the manufacturer’s quality system covering design, production, final inspection and testing, and monitors it through regular audits. | Large manufacturers with many models and variants and an established quality management system. |
As Notified Body No. 2908, TESTPLUS performs conformity assessment under all three procedures of 2000/14/EC: Annex VI, Annex VII and Annex VIII. Measurements can be carried out at your production facility or on site.
Noise Label and EC Declaration of Conformity
Every compressor placed on the market must bear, next to the CE marking, the noise label showing the guaranteed sound power level (the LWA … dB mark) in a visible, legible and indelible form. The EC declaration of conformity must contain at least the following:
- Name and address of the manufacturer (or its authorised representative),
- Description of the equipment: type, make/trade name, serial number, net installed power (kW),
- The conformity assessment procedure applied (Annex VI, Annex VII or Annex VIII),
- Name, address and identification number of the notified body involved (e.g. NB 2908),
- The measured sound power level and the guaranteed sound power level for this type,
- References to 2000/14/EC and to any other legislation applied (2006/42/EC, 2014/30/EU, etc.),
- Place and date of issue, and the signature of the authorised person.
The guaranteed value is determined by adding the measurement uncertainty and production variations to the measured sound power level, and it must not exceed the limit value. The label shows the guaranteed value, not the measured one.
Noise Compliance Checklist
You can check the compliance of your compressors in terms of noise emission against the following points:
- Does the EC Declaration of Conformity refer to 2000/14/EC? Are the procedure (Annex VI/VII/VIII) and the notified body number stated in it?
- Is there a notified body certificate, and does it cover the model/power range on the market?
- Is the noise label on the product, is the guaranteed value the same as in the declaration, and is it below the limit? (You can check with the calculator above.)
- Has the noise test report been prepared according to the Annex III test code and EN ISO 3744?
- Is the technical documentation up to date; is the power value on the product consistent with the declaration?
- Can it be verified that series production is identical to the certified type (changes to the engine, the compressor block, the enclosure or the silencer)?
The Machinery Safety Side: 2006/42/EC and (EU) 2023/1230
Compressors are also covered by the Machinery Directive 2006/42/EC. As compressors are not listed in Annex IV of the Machinery Directive, the involvement of a notified body is not mandatory for machinery safety. An assessment by an independent body nevertheless strengthens the manufacturer’s position with customers and in tenders.
TESTPLUS provides voluntary certification of compressors for machinery safety. The main standards used in examination and testing are:
- EN 1012-1: Compressors and vacuum pumps – Safety requirements – Part 1: Air compressors,
- EN ISO 12100: Risk assessment and risk reduction,
- EN 60204-1: Electrical equipment of machines.
From 20 January 2027, the Machinery Regulation (EU) 2023/1230 will replace 2006/42/EC in the EU; on the noise side, 2000/14/EC continues to apply.
Frequently Asked Questions
Are electrically driven compressors also subject to the noise limit?
Yes; the Directive makes no distinction by type of drive. Compressors designed for use outdoors with a net installed power below 350 kW are subject to the limit regardless of whether they have an electric motor or a combustion engine.
Which value should I take as the net installed power?
The rated (net) power on the nameplate of the engine driving the compressor is used. Powers given in HP are converted using 1 HP = 0.7457 kW.
I make different pressure versions in the same enclosure; is a measurement needed for each?
The guaranteed value is declared separately for each type. The effect of different pressure/flow versions on noise is assessed with the notified body on the basis of the technical documentation; where necessary, the noisiest version is measured.
Which procedure suits a small number of special compressors?
For one-off or small-quantity products, Annex VII (unit verification) is the most practical route.
For the equipment lists under 2000/14/EC, the conformity assessment procedures, the noise limit calculator and the documents requested for imports, see our noise certification (2000/14/EC CE certification) page.
How Does the Process Work with TESTPLUS?
- Application: You apply with the product information (model list, power values, existing declaration and reports).
- Choice of procedure: The Annex VI, Annex VII or Annex VIII procedure is determined according to your production set-up.
- Measurement and examination: Noise measurements are carried out at your production facility or on site using accredited methods; the technical documentation is assessed.
- Certification: Once conformity is established, the notified body certificate (NB 2908) is issued; periodic surveillance continues under Annex VI and Annex VIII.
- Machinery safety (optional): A voluntary machinery safety assessment can be carried out during the same visit.
