ISO 10816-1 Standard and Instrumental Implementation of Vibration Diagnostics Using the Balanset-1A System

Abstract

This report presents a comprehensive analysis of international regulatory requirements for the vibration condition of industrial equipment defined in ISO 10816-1 and its derivative standards. The document reviews the evolution of standardization from ISO 2372 to the current ISO 20816, explains the physical meaning of the measured parameters, and describes the methodology for evaluating the severity of vibration conditions. Special attention is given to the practical implementation of these rules using the portable balancing and diagnostic system Balanset-1A. The report contains a detailed description of the technical characteristics of the instrument, algorithms of its operation in vibrometer and balancing modes, and methodological guidelines for performing measurements to ensure compliance with reliability and safety criteria for rotating machinery.

Chapter 1. Theoretical Foundations of Vibration Diagnostics and Evolution of Standardization

1.1. Physical Nature of Vibration and Selection of Measurement Parameters

Vibration, as a diagnostic parameter, is the most informative indicator of the dynamic condition of a mechanical system. Unlike temperature or pressure, which are integral indicators and often react to faults with a delay, the vibration signal carries information about the forces acting inside the mechanism in real time.

The ISO 10816-1 standard, like its predecessors, is based on measuring vibration velocity. This choice is not accidental and follows from the energetic nature of damage. Vibration velocity is directly proportional to the kinetic energy of the oscillating mass and therefore to the fatigue stresses that arise in machine components.

Vibration diagnostics uses three main parameters, each with its own field of application:

Vibration displacement (Displacement): The oscillation amplitude measured in micrometers (µm). This parameter is critical for low-speed machines and for evaluating clearances in journal bearings, where it is important to prevent rotor-to-stator contact. In the context of ISO 10816-1, displacement has limited use, because at high frequencies even small displacements can generate destructive forces.

Vibration velocity (Velocity): The surface point velocity measured in millimeters per second (mm/s). This is a universal parameter for the frequency range from 10 to 1000 Hz, which covers the main mechanical defects: unbalance, misalignment, and looseness. ISO 10816 adopts vibration velocity as the primary assessment criterion.

Vibration acceleration (Acceleration): The rate of change of vibration velocity measured in meters per second squared (m/s²) or in g units. Acceleration characterizes inertial forces and is most sensitive to high-frequency processes (from 1000 Hz and above), such as early-stage rolling bearing defects or gear mesh problems.

ISO 10816-1 focuses on broadband vibration in the range 10–1000 Hz. This means that the instrument must integrate the energy of all oscillations within this band and output a single value — the root mean square (RMS) value. Using RMS instead of peak value is justified because RMS characterizes the total power of the oscillatory process over time, which is more relevant for evaluating thermal and fatigue impact on the mechanism.

1.2. Historical Context: From ISO 2372 to ISO 20816

Understanding current requirements requires analyzing their historical development.

ISO 2372 (1974): The first global standard that introduced the classification of machines by power. It defined machine classes (Class I – Class IV) and evaluation zones (A, B, C, D). Although it was officially withdrawn in 1995, the terminology and logic of this standard are still widely used in engineering practice.

ISO 10816-1 (1995): This standard replaced ISO 2372 and ISO 3945. Its key innovation was a clearer distinction of requirements depending on foundation type (rigid versus flexible). The standard became an “umbrella” document that defines general principles (Part 1), while specific limit values for different machine types were moved to subsequent parts (Part 2 — steam turbines, Part 3 — industrial machines, Part 4 — gas turbines, etc.).

ISO 20816-1 (2016): The modern iteration of the standard. ISO 20816 combines the 10816 series (vibration of non-rotating parts) and the 7919 series (vibration of rotating shafts). This is a logical step, because full assessment of critical equipment requires analyzing both parameters. However, for most general-purpose industrial machines (fans, pumps), where access to the shaft is difficult, the methodology based on housing measurements introduced in ISO 10816 remains dominant.

This report focuses on ISO 10816-1 and ISO 10816-3, because these documents are the main working tools for about 90% of industrial equipment diagnosed with portable instruments such as Balanset-1A.

Chapter 2. Detailed Analysis of ISO 10816-1 Methodology

2.1. Scope and Limitations

ISO 10816-1 applies to vibration measurements carried out on non-rotating parts of machines (bearing housings, feet, supporting frames). The standard does not apply to vibration caused by acoustic noise and does not cover reciprocating machines (they are covered by ISO 10816-6) which generate specific inertial forces due to their operating principle.

A critical aspect is that the standard regulates in-situ measurements — in real operating conditions, not only on a test stand. This means that the limits account for the influence of the real foundation, piping connections, and operating load conditions.

2.2. Equipment Classification

A key element of the methodology is the division of all machines into classes. Applying Class IV limits to a Class I machine may cause an engineer to miss a dangerous condition, while the opposite may lead to unjustified shutdowns of healthy equipment.

According to Annex B of ISO 10816-1, machines are divided into the following categories:

Table 2.1. Machine Classification According to ISO 10816-1

Sinif	Description	Typical Machines	Vəqf növü
Class I	Individual parts of engines and machines, structurally connected to the aggregate. Small machines.	Electric motors up to 15 kW. Small pumps, auxiliary drives.	Hər hansı
Class II	Medium-sized machines without special foundations.	Electric motors 15–75 kW. Engines up to 300 kW on a rigid base. Pumps, fans.	Usually rigid
Class III	Large prime movers and other large machines with rotating masses.	Turbines, generators, high-power pumps (>75 kW).	Sərt
Class IV	Large prime movers and other large machines with rotating masses.	Turbogenerators, gas turbines (>10 MW).	Çevik

Problem of identifying foundation type (Rigid vs Flexible):

The standard defines a foundation as rigid if the first natural frequency of the “machine–foundation” system is above the main excitation frequency (rotational frequency). A foundation is flexible if its natural frequency is below the rotational frequency.

In practice this means:

• A machine bolted to a massive concrete shop floor usually belongs to a class with a rigid foundation.
• A machine mounted on vibration isolators (springs, rubber pads) or on a light steel frame (for example, an upper-tier structure) belongs to a class with a flexible foundation.

This distinction is critical because a machine on a flexible foundation can vibrate with higher amplitude without creating dangerous internal stresses. Therefore, limits for Class IV are higher than for Class III.

2.3. Vibration Evaluation Zones

Instead of a binary “good/bad” evaluation, the standard offers a four-zone scale that supports condition-based maintenance.

Zona A (Yaxşı): Vibration level for newly commissioned machines. This is the reference condition to achieve after installation or major overhaul.

B zonası (Qənaətləndirici): Machines fit for unrestricted long-term operation. The vibration level is higher than ideal but does not threaten reliability.

Zona C (Qeyri-qənaətbəxş): Machines unfit for long-term continuous operation. Vibration reaches a level where accelerated degradation of components (bearings, seals) starts. Operation is possible for a limited time under enhanced monitoring until the next planned maintenance.

D zonası (qəbuledilməz): Vibration levels that may cause catastrophic failure. Immediate shutdown is required.

2.4. Vibration Limit Values

The table below summarizes the limit values of RMS vibration velocity (mm/s) according to Annex B of ISO 10816-1. These values are empirical and serve as guidelines if the manufacturer’s specifications are not available.

Table 2.2. Vibration Zone Limits (ISO 10816-1 Annex B)

Zone Boundary	Class I (mm/s)	Class II (mm/s)	Class III (mm/s)	Class IV (mm/s)
A / B	0.71	1.12	1.80	2.80
B / C	1.80	2.80	4.50	7.10
C / D	4.50	7.10	11.20	18.00

Analytical interpretation. Consider the value 4.5 mm/s. For small machines (Class I) this is the boundary of the emergency condition (C/D), which requires shutdown. For medium-sized machines (Class II) this is the middle of the “requires attention” zone. For large machines on a rigid foundation (Class III) this is only the boundary between “satisfactory” and “unsatisfactory” zones. For machines on a flexible foundation (Class IV) this is a normal operating vibration level (Zone B).

This progression shows the risk of using universal limits. An engineer who uses the rule “4.5 mm/s is bad” for all machines may either miss the failure of a small pump or unjustifiably reject a large turbocompressor.

Chapter 3. Specifics of Industrial Machines: ISO 10816-3

While ISO 10816-1 defines the general framework, in practice most industrial units (pumps, fans, compressors above 15 kW) are governed by the more specific Part 3 of the standard (ISO 10816-3). It is important to understand the difference because Balanset-1A is often used to balance fans and pumps covered by this part.

3.1. Machine Groups in ISO 10816-3

Unlike the four classes in Part 1, Part 3 divides machines into two main groups:

Qrup 1: Large machines with rated power above 300 kW. This group also includes electrical machines with shaft height greater than 315 mm.

Qrup 2: Medium-sized machines with rated power from 15 kW to 300 kW. This group includes electrical machines with shaft height from 160 mm to 315 mm.

3.2. Vibration Limits in ISO 10816-3

The limits here also depend on foundation type (Rigid/Flexible).

Table 3.1. Vibration Limits According to ISO 10816-3 (RMS, mm/s)

Condition (Zone)	Group 1 (>300 kW) Rigid	Group 1 (>300 kW) Flexible	Group 2 (15–300 kW) Rigid	Group 2 (15–300 kW) Flexible
A (New)	< 2.3	< 3.5	< 1.4	< 2.3
B (Long-term operation)	2.3 – 4.5	3.5 – 7.1	1.4 – 2.8	2.3 – 4.5
C (Limited operation)	4.5 – 7.1	7.1 – 11.0	2.8 – 4.5	4.5 – 7.1
D (Damage)	> 7.1	> 11.0	> 4.5	> 7.1

Data synthesis. Comparing ISO 10816-1 and ISO 10816-3 tables shows that ISO 10816-3 imposes stricter requirements on medium-power machines (Group 2) on rigid foundations. The boundary of Zone D is set at 4.5 mm/s, which coincides with the limit for Class I in Part 1. This confirms the trend toward stricter limits for modern, faster, and lighter equipment. When using Balanset-1A to diagnose a 45 kW fan on a concrete floor, you should focus on the “Group 2 / Rigid” column of this table, where the transition to the emergency zone occurs at 4.5 mm/s.

Chapter 4. Hardware Architecture of the Balanset-1A System

To implement the requirements of ISO 10816/20816, you need an instrument that provides accurate and repeatable measurements and matches the required frequency ranges. The Balanset-1A system developed by Vibromera is an integrated solution that combines the functions of a two-channel vibration analyzer and a field balancing instrument.

4.1. Measurement Channels and Sensors

The Balanset-1A system has two independent vibration measurement channels (X1 and X2), which allows simultaneous measurements at two points or in two planes.

Sensor type. The system uses accelerometers (vibration transducers that measure acceleration). This is the modern industry standard because accelerometers provide high reliability, wide frequency range, and good linearity.

Signal integration. Because ISO 10816 requires evaluation of vibration velocity (mm/s), the signal from the accelerometers is integrated in hardware or software. This is a critical signal processing step, and the quality of the analog-to-digital converter plays a key role.

Measurement range. The instrument measures vibration velocity (RMS) in the range from 0.05 to 100 mm/s. This range fully covers all ISO 10816 evaluation zones (from Zone A < 0.71 to Zone D > 45 mm/s).

4.2. Frequency Characteristics and Accuracy

The metrological characteristics of Balanset-1A fully comply with the requirements of the standard.

Frequency range. The basic version of the instrument operates in the 5 Hz – 550 Hz band.

The lower limit of 5 Hz (300 rpm) even exceeds the standard ISO 10816 requirement of 10 Hz and supports diagnostics of low-speed machines. The upper limit of 550 Hz covers up to the 11th harmonic for machines with a rotational frequency of 3000 rpm (50 Hz), which is sufficient to detect unbalance (1×), misalignment (2×, 3×), and looseness. Optionally, the frequency range can be extended to 1000 Hz, which fully covers standard requirements.

Amplitude accuracy. The amplitude measurement error is ±5% of full scale. For operational monitoring tasks, where zone boundaries differ by hundreds of percent, this accuracy is more than sufficient.

Phase accuracy. The instrument measures phase angle with an accuracy of ±1 degree. Although phase is not regulated by ISO 10816, it is critically important for the next step — balancing.

4.3. Tachometer Channel

The kit includes a laser tachometer (optical sensor) that performs two functions:

• Measures rotor speed (RPM) from 150 to 60,000 rpm (in some versions up to 100,000 rpm). This makes it possible to identify whether vibration is synchronous with rotational frequency (1×) or asynchronous.
• Generates a reference phase signal (phase mark) for synchronous averaging and calculating correction mass angles during balancing.

4.4. Connections and Layout

The standard kit includes sensor cables 4 meters long (optional 10 meters). This increases safety during in-situ measurements. Long cables let the operator stay at a safe distance from rotating machine parts, which meets industrial safety requirements for working with rotating equipment.

Chapter 5. Measurement Methodology and ISO 10816 Evaluation Using Balanset-1A

This chapter describes a step-by-step algorithm for using the Balanset-1A instrument to perform vibration assessments.

5.1. Preparation for Measurements

Identify the machine. Determine the machine class (according to Chapters 2 and 3 of this report). For example, a “45 kW fan on vibration isolators” belongs to Group 2 (ISO 10816-3) with a flexible foundation.

Software installation. Install Balanset-1A drivers and software from the supplied USB drive. Connect the interface unit to the laptop’s USB port.

Mount the sensors.

• Install sensors on bearing housings. Do not mount them on thin covers.
• Use magnetic bases. Make sure the magnet sits firmly on the surface. Paint or rust under the magnet acts as a damper and reduces high-frequency readings.
• Maintain orthogonality: perform measurements in vertical (V), horizontal (H), and axial (A) directions. Balanset-1A has two channels, so you can measure, for example, V and H simultaneously at one support.

5.2. Vibrometer Mode (F5)

Balanset-1A software has a dedicated mode for ISO 10816 evaluation.

• Run the program.
• Press F5 (or click the “F5 – Vibrometer” button in the interface). A multichannel vibrometer window opens.
• Press F9 (Run) to start data acquisition.

Indicator analysis.

• RMS (Total): The instrument displays overall RMS vibration velocity (V1s, V2s). This is the value you compare with the standard’s tabulated limits.
• 1× Vibration: The instrument extracts the vibration amplitude at rotational frequency.

If the RMS value is high (Zone C/D) but the 1× component is low, the problem is not unbalance. It may be a bearing fault, cavitation (for a pump), or electromagnetic issues. If RMS is close to the 1× value (for example, RMS = 10 mm/s, 1× = 9.8 mm/s), unbalance dominates and balancing will reduce vibration by about 95%.

5.3. Spectral Analysis (FFT)

If overall vibration exceeds the limit (Zone C or D), you must identify the cause. The F5 mode includes a Charts tab.

Spectrum. The spectrum shows amplitude versus frequency.

• A dominant peak at 1× (rotational frequency) indicates unbalance.
• Peaks at 2×, 3× indicate misalignment or looseness.
• High-frequency “noise” or a forest of harmonics indicates rolling bearing defects.
• The blade passing frequency (number of blades × rpm) indicates aerodynamic problems in a fan or hydraulic problems in a pump.

Balanset-1A provides these visualizations, which turns it from a simple “compliance meter” into a full diagnostic tool.

Chapter 6. Balancing as a Correction Method: Practical Use of Balanset-1A

When diagnostics (based on 1× dominance in the spectrum) indicate unbalance as the main cause of ISO 10816 limit exceedance, the next step is balancing. Balanset-1A implements the influence coefficient method (three-run method).

6.1. Balancing Theory

Unbalance occurs when the rotor’s center of mass does not coincide with its axis of rotation. This causes a centrifugal force F = m · r · ω² that generates vibration at rotational frequency. The goal of balancing is to add a correction mass (weight) that produces a force equal in magnitude and opposite in direction to the unbalance force.

6.2. Single-Plane Balancing Procedure

Use this procedure for narrow rotors (fans, pulleys, disks).

Setup.

• Mount the vibration sensor (Channel 1) perpendicular to the axis of rotation.
• Set up the laser tachometer and place one reflective tape mark on the rotor.
• In the program, select F2 – Single Plane.

Run 0 – Initial.

• Start the rotor. Press F9. The instrument measures the initial vibration (amplitude and phase).
• Example: 8.5 mm/s at 120°.

Run 1 – Trial Weight.

• Stop the rotor.
• Mount a trial weight of known mass (for example, 10 g) at an arbitrary location.
• Start the rotor. Press F9. The instrument records the change in the vibration vector.
• Example: 5.2 mm/s at 160°.

Calculation and correction.

• The program automatically calculates the mass and angle of the correction weight.
• For example, the instrument may instruct: “Add 15 g at an angle of 45° from the trial weight position.”
• Balanset functions support split weights: if you cannot place the weight at the calculated location, the program splits it into two weights for mounting, for example, on fan blades.

Run 2 – Verification.

• Install the calculated correction weight (removing the trial weight if the program requires it).
• Start the rotor and make sure that residual vibration has dropped to Zone A or B according to ISO 10816 (for example, below 2.8 mm/s).

6.3. Two-Plane Balancing

Long rotors (shafts, crusher drums) require dynamic balancing in two correction planes. The procedure is similar but requires two vibration sensors (X1, X2) and three runs (Initial, Trial weight in Plane 1, Trial weight in Plane 2). Use F3 mode for this procedure.

Chapter 7. Practical Scenarios and Interpretation (Case Studies)

Scenario 1: Industrial Exhaust Fan (45 kW)

Context. The fan is installed on a roof on spring-type vibration isolators.

Classification. ISO 10816-3, Group 2, flexible foundation.

Measurement. Balanset-1A in F5 mode shows RMS = 6.8 mm/s.

Analysis.

• According to Table 3.1, the B/C boundary for “Flexible” is 4.5 mm/s, and the C/D boundary is 7.1 mm/s.

Conclusion. The fan operates in Zone C (limited operation), approaching the emergency Zone D.

Diagnostics. The spectrum shows a strong 1× peak.

Action. Balancing is required. After balancing with Balanset-1A, vibration level dropped to 1.2 mm/s (Zone A). The failure was prevented.

Scenario 2: Boiler Feed Pump (200 kW)

Context. The pump is rigidly mounted on a massive concrete foundation.

Classification. ISO 10816-3, Group 2, rigid foundation.

Measurement. Balanset-1A shows RMS = 5.0 mm/s.

Analysis.

• According to Table 3.1, the C/D boundary for “Rigid” is 4.5 mm/s.

Conclusion. The pump operates in Zone D (emergency condition). A value of 5.0 mm/s is already unacceptable for rigid mounting.

Diagnostics. The spectrum shows a series of harmonics and a high noise level. The 1× peak is low.

Action. Balancing will not help. The problem is likely in the bearings or cavitation. The pump must be stopped for mechanical inspection.

Chapter 8. Conclusion

ISO 10816-1 and its specialized Part 3 provide a fundamental basis for ensuring industrial equipment reliability. Transition from subjective perception to quantitative assessment of vibration velocity (RMS, mm/s) lets engineers objectively classify machine condition and plan maintenance based on actual condition.

Instrumental implementation of these standards using the Balanset-1A system has proven effective. The instrument provides metrologically accurate measurements in the 5–550 Hz range (fully covering standard requirements for most machines) and offers the functionality required to identify the causes of elevated vibration (spectral analysis) and eliminate them (balancing).

For operating companies, implementing regular monitoring based on the ISO 10816 methodology and instruments such as Balanset-1A is a direct investment in reducing operating costs. The ability to distinguish Zone B from Zone C helps avoid both premature repairs of healthy machines and catastrophic failures caused by ignoring critical vibration levels.

End of report