Evaluation of machine vibrations based on DIN ISO 10816-3
The scope of this standard includes steam turbines up to 50 MW, electric motors and fans. Because the scope is quite wide, the standard is explained in more detail below. The standard aims to classify the machine state in four different classes by means of vibration data for acceptance measurements and operational monitoring.
Assessment criteria according to the standard are the RMS value of the vibration velocity and the RMS value of the vibration displacement. Usually it is sufficient to measure the vibration velocity. The additional evaluation of the vibration displacement is recommended if low frequency components are encountered. If both vibration parameters are logged and analyzed, the poorer of the two determined classes is applied.
The frequency range of the vibrations to be captured depends on the machine speed:
- 10 Hz to 1000 Hz for speeds of more than 600 rpm
- 2 Hz to 1000 Hz for speeds of less than 600 rpm
Suitable measuring points are characterized by the fact that they reflect the dynamic forces of the machine as purely as possible. For example, locations where local resonances occur are not suitable. Suitable locations tend to be bearing stands and bearing covers; measurements are usually carried out in two orthogonal directions.
The classification also takes into account the machine substructure, subdivided into rigid and elastic substructures. If the lowest natural frequency of the whole system consisting of machine and substructure is at least 25% higher than the main exciting frequency (generally the rotational frequency), the substructure can be regarded as rigid, otherwise as elastic. This evaluation should be carried out separately for each measuring direction (two orthogonal directions, see above).
The class according to ISO 10816-3 is determined for each two channels and stored in the variables ISOClassIsVel (for the classification with regard to the vibration velocity) and ISOClassIsDispl (for the classification with regard to the vibration displacement). This sample results in four classifications. Vibration Association Association Canadienne ACVM n Vibration Machines Guidelines for Evaluating Vibration Based on ISO 10816-3:1998(E). Study the standard in order to correctly interpret the chart. The vibration levels refer to radial vibration on all bearings and axial vibration on thrust bearings. Black and dark grey require repair.
DIN ISO 10816-3:2009 describes four evaluation zones (A, B, C, D), with limit values as listed in the following table.
Machine group | 1 | 2 | |||
Installation | rigid | elastic | rigid | elastic | |
RMS value of the vibration velocity in mm/s | 11,00 .. ∞ | D | D | D | D |
7.10 .. 11.00 | D | C | D | D | |
4.50 .. 7.10 | C | B | D | C | |
3,50 .. 4,50 | B | B | C | B | |
2.80 .. 3.50 | B | A | C | B | |
2.30 .. 2.80 | B | A | B | B | |
1.40 .. 2.30 | A | A | B | A | |
0.00 .. 1.40 | A | A | A | A | |
Machine group | 1 | 2 | |||
Installation | rigid | elastic | rigid | elastic | |
RMS value of the vibration displacement in µm | 140 .. ∞ | D | D | D | D |
113 .. 140 | D | C | D | D | |
90 .. 113 | D | C | D | C | |
71 .. 90 | C | B | D | C | |
57 .. 71 | C | B | C | B | |
45 .. 57 | B | B | C | B | |
37 .. 45 | B | A | B | B | |
29 .. 37 | B | A | B | A | |
22 .. 29 | A | A | B | A | |
0 .. 22 | A | A | A | A | |
Zone A | The vibrations of recently commissioned machines tend to be in this zone. |
Zone B | Machines with vibrations in this zone are usually regarded as suitable for continuous operation without restrictions. |
Zone C | Machines with vibrations in this zone are usually regarded as unsuitable for continuous operation. The machine may generally be operated in this state for a limited period, until a suitable opportunity for remedial measures arises. |
Zone D | Vibration values in this zone are usually regarded as dangerous in the sense that damage to the machine may occur. |
Machine group 1 | Large machines with a rated output of 300 kW to 50 MW and electrical machines with a shaft height of more than 315 mm |
Machine group 2 | Medium-sized machines with a rated output of 15 kW to 300 kW and electrical machines with a shaft height between 160 mm and 315 mm |
Disclaimer: The author is not trying to present himself as an authority on all available CM standards. This blog post is simply an attempt to help those who may be unaware that such guidance exists or of the extent of such standards.
We previously introduced a series of international standards pertaining to condition monitoring of industrial equipment with vibration analysis in, This series ends with the numeric sequence of xx816-x. The original standards from 1974 (ISO 2372) and 1985 (ISO 3945) were replaced or superseded by ISO 10816-1 in 1995. 10816-1 was amended in 2009 and then replaced by ISO 20816-1 in 2016. Next (numerically) is the standard we also mentioned in our previous blog, 20816-2. The dash 2 standard covers the measurement and evaluation of vibration on large land-based gas or steam turbines and generators.
The subsequent standard in the series, the “dash 3” standard is the focus of this blog. This standard is titled:
INTERNATIONAL STANDARD ISO 10816-3
Mechanical vibration — Evaluation of machine vibration by measurements on non-rotating parts
Part 3: Industrial machines with nominal power above 15 kW and nominal speeds between 120 r/min and 15 000 r/min when measured in situ
ISO 10816-3 is the current standard in the series that covers a general range of equipment types and sizes. When first created it was the “catch-all” standard used for many types of machines (such as centrifugal pumps which are now covered by the dash 7 standard) that have since come to be covered by their own specific part of the series. The “10816” issuance of the dash 3 standard is still in force, but to be current it must be joined by a 2017 amendment, “Amendment 1”. This amendment actually modifies the scope of the standard, so it is critical to its being considered current.
The scope of this standard is quoted below from the ISO.org preview page (quotation in bold).
Important Note: The scope shown in the preview cannot be considered current because it is modified by Amendment 1.
Scope:
This part of ISO 10816 gives criteria for assessing vibration levels when measurements are made in situ. The criteria specified apply to machine sets having power above 15 kW and operating speeds between 120 r/min and 15 000 r/min.
The machine sets covered by this part of ISO 10816 include:
- steam turbines with power up to 50 MW
- steam turbine sets with power greater than 50 MW and speeds below 1 500 r/min or above 3 600 r/min (not included in ISO 10816-2)
- rotary compressors
- industrial gas turbines with power up to 3 MW
- generators
- electrical motors of any type
- blowers or fans
NOTE: However, the vibration criteria presented in this part of ISO 10816 are generally only applicable to fans with power ratings greater than 300 kW or fans that are not flexibly supported. As and when circumstances permit, recommendations for other types of fans, including those with lightweight sheet metal construction, will be prepared. Until such time, classifications can be agreed upon between the manufacturer and the customer, using results of previous operational experience, see also ISO 14694[4].
The following are excluded from this part of ISO 10816:
- land-based steam turbine generator sets with power greater than 50 MW and speeds of 1 500 r/min, 1 800 r/min, 3 000 r/min, or 3 600 r/min (see ISO 10816-2)
- gas turbine sets with power greater than 3 MW (see ISO 10816-4)
- machine sets in hydraulic power generating and pumping plants (see ISO 10816-5)
- machines coupled to reciprocating machines (see ISO 10816-6)
- rotodynamic pumps including integrated electric motors, i.e. where the impeller is mounted directly on the motor shaft or is rigidly attached to it (see ISO 10816-7)
- rotary positive displacement compressors (e. g. screw compressors)
- reciprocating compressors
- reciprocating pumps
- submerged motor-pumps
- wind turbines
The criteria of this part of ISO 10816 apply to in situ broad-band vibration measurements taken on the bearings, bearing pedestals, or housing of machines under steady-state operating conditions within the nominal operating speed range. They relate to both acceptance testing and operational monitoring. The evaluation criteria of this part of ISO 10816 are designed to apply to both continuous and non-continuous monitoring situations.
This part of ISO 10816 encompasses machines that may have gears or rolling element bearings but does not address the diagnostic evaluation of the condition of those gears or bearings.
Iso 10816 3 Chart Pdf
The criteria are applicable only for the vibration produced by the machine set itself and not for vibration which is transmitted to the machine set from external sources.
Iso 10816 3 2014 Free
To read the ISO’s preview of this standard, click here.