CONSTRUCTION STANDARD SPECIFICATION

SECTION 15200

[VIBRATION LIMITS AND CONTROL]{.underline}

Page

PART 1 - GENERAL

1.01 Summary [2](#summary)

1.02 References [2](#references)

1.03 Submittals [2](#submittals)

1.04 Quality Assurance [2](#quality-assurance)

PART 2 - PRODUCTS

2.01 Vibration Isolators [3](#vibration-isolators)

2.02 Vibration Measurement Device [3](#vibration-measurement-device)

PART 3 - EXECUTION

3.01 Installation [4](#installation)

3.02 Vibration Testing [4](#vibration-testing)

3.03 Vibration Limits [6](#vibration-limits)

3.04 Vibrations Measurement Report [7](#vibrations-measurement-report)

3.05 Resonance [8](#resonance)

CONSTRUCTION STANDARD SPECIFICATION

SECTION 15200

[VIBRATION LIMITS AND CONTROL]{.underline}

# PART 1 - GENERAL

## 1.01 SUMMARY

Section includes types of vibration isolators required for different
systems, and establishes maximum acceptable limits for vibration of
machines with five horsepower or greater, in terms of:

A. Balance level in displacement (mils) as filtered measurement at
rotating speed.

B. Overall velocity (in/sec) in 10 - 1,000 Hz band.

C. Bearing quality or condition by measuring overall acceleration in 0 -
5,000 Hz band, which indicates severity of metal-to-metal contact by
detecting shock pulses. This measurement is normalized to speed.

## 1.02 REFERENCES

American National Standards Institute (ANSI)

S2.2-1959 (R1990) Methods for the Calibration of Shock and vibration
Pickups

## 1.03 SUBMITTALS

A. General: Submit the following items in accordance with the Conditions
of Contract and Section 01330, \"Submittal Procedures."

B. Vibration Report: Submit in accordance with specified requirements of
Part 3.

## 1.04 QUALITY ASSURANCE

Contractor is required to demonstrate to Sandia that equipment complies
with requirements of this specification. Measurements can be taken
elsewhere, and documents submitted as evidence of passage; but final
acceptance judgement shall be made from measurements taken on site in
equipment's final, installed location and operating configuration.
Equipment shall not be accepted until fully compliant with specified
requirements.

# PART 2 - PRODUCTS

## 2.01 VIBRATION ISOLATORS

Spring and Resilient Pad Hangars: Stable steel spring and neoprene
isolator placed in series, and encased in welded steel bracket, with
allowance for rod misalignment up to 15 degrees without
short-circuiting. Provide Mason Industries, Inc., Model PC30N, or
approved equal.

## 2.02 VIBRATION MEASUREMENT DEVICE

A. General

1\. Capable of filtered displacement readings at rotational speed.

a\. Provide separate speed-measuring device, such as strobe light, photo
tachometer, or mechanical tachometer, to measure rotating speed of
belt-driven or variable-speed machines.

b\. Displacement Readings: Mils (0.001 inch), peak-to-peak.

c\. Filter Bandwidth: Sufficiently narrow to achieve accuracy of ± 10
percent from absolute value.

2\. Velocity Measurement: Overall in 10 to 1,000 Hz bandwidth, readings
in inches per second, peak.

3\. Acceleration Measurement: Overall in 0 to 5,000 Hz bandwidth,
readings in *g*, peak.

a\. Capability to record and plot waveform with 100-microsecond
resolution (5,000-Hz frequency span and 500 lines with Fast Fourier
Transform (FFT) analyzer).

b\. Record and plot waveform for acceleration level failures to aid
analysis.

4\. FFT analyzer with accelerometer can meet the above requirements.

B. Calibration of Complete Instrumentation System: Includes transducer,
signal conditioning, cable, and readout instrument. Calibrate in
accordance with one of the methods in ANSI S2.2.

1\. Comparison calibration is acceptable.

2\. Calibration of transducer alone is unacceptable; final reading is
dependent on settings in readout instrument (like windows, filters,
averaging method, calibration constants, and frequency span).

C. Frequency Response: Linear (within ± 10 percent) in 1 to 5,000 Hz
range.

Internally generated noise or external signals that are not vibration,
shall be less than 1 percent of upper limit under test (signal-to-noise
ratio shall be 100 to 1). Noise is defined as any signal level displayed
that is not vibration.

D. Recording and Plotting Capability: Capable of recording frequency
spectrum and time plot, and plotting on paper.

1\. Both plots unfiltered below 5,000 Hz.

2\. Spectrum Frequency Resolution: No coarser than 1/200 of full span
frequency (200-line spectrum analyzer or finer is suitable).

3\. Digital integration of accelerometer signal to velocity or
displacement is acceptable.

# PART 3 - EXECUTION

## 3.01 INSTALLATION

A. Piping Systems: Connect refrigerant piping to compressors with
refrigerant-rated, flexible metallic sections, oriented parallel to
crankshaft.

1\. Use flexible connections parallel to crankshaft to connect building
air piping to air compressors.

2\. When piping vibration hangars are specified, provide spring hanger
isolators as described in Part 2.

B. Ductwork: Attach to fans with weatherproof, flame-retardant flexible
connections.

When duct vibration hangars are specified, provide spring hanger
isolators described in Part 2.

## 3.02 VIBRATION TESTING

A. Perform vibration testing after equipment alignment and balance.

B. Obtain vibration measurements after Test and Balance is complete. The
machines shall be at their normal operating conditions (such as normal
speed, normal loading, and producing flow or energy) for which the
system was designed.

C. Determine and record equipment operating speeds with tachometer or
strobe. Indicate both driving and driven speeds.

D. Check isolation system for proper operation, if applicable:

1\. Visually inspect equipment installation. Verify that isolators
supporting piece of equipment have approximately the same deflection.

2\. Apply unbalanced load and verify that system moves freely.

3\. Determine actual isolator deflection and compare to specified value.

E. Vibration Measurements: Obtain at each bearing, or as close to
bearing on structure as practical. For machines housed in rigid casing,
such as electric motors or vaneaxial fans, obtain measurements at each
end of machine.

1\. Obtain three orthogonal measurements at each bearing, typically in
horizontal, vertical, and axial directions. For unusual configurations,
three orthogonal measurements in other orientations are allowed.

2\. Hand-held probing is allowed. Magnetic mounting of transducers is
preferred. Adjust magnet on rough surfaces so that it is stable and does
not rock.

F. Safety: Exercise extreme caution when obtaining vibration
measurements on operating machinery.

1\. Measurement points may be deleted if it poses unnecessary risk, in
the opinion of person taking measurements.

2\. Judgement of equipment's vibration acceptability will be made from
pattern of remaining measurements by the Sandia Delegated Representative
(SDR).

3\. If necessary, machine may be stopped to attach transducers and
secure cables, and this stop-start pattern repeated for each measurement
point.

4\. Obtain SDR's approval prior to deleting measurement points, and
stopping and starting equipment.

G. Operate variable-speed machines throughout their entire range, at
each measurement point, and observe for resonance. Measure and record
vibration at minimum of three operating speeds. Vibration levels must be
acceptable at all three test speeds.

1\. Maximum speed.

2\. Speed which produces highest reading at each measuring point.

3\. Expected normal operating speed.

H. It is acceptable to take measurements over a period of time and
statistically average the readings. It is recognized that vibration is
mostly steady state, but it is also dynamic, changes with time, and
external transients can influence readings.

Digital and analog readings can be averaged visually. Summation
averaging with FFT analyzer is acceptable. Time period of observation,
or averaging, shall be minimum of 10 seconds.

## 3.03 VIBRATION LIMITS

A. Maximum allowable measurements for various pieces of equipment are
shown below:

> **TABLE 1**
>
> **Vibration Limits**

+----------------------+------------------+--------------+-------------+
| **Equipment**        | **Balance        | Overall      | Overall     |
|                      | Condition**      | Velocity     | A           |
|                      |                  |              | cceleration |
|                      | **Displacement** | (in/sec,     |             |
|                      |                  | Peak         | (g, Peak    |
|                      | (mils, P-P at 1X |              |             |
|                      | rpm)             | 10 - 1,000   | 0 - 5,000   |
|                      |                  | Hz)          | Hz)         |
+----------------------+------------------+--------------+-------------+
| Electric Motors:     |                  |              |             |
+----------------------+------------------+--------------+-------------+
| 1,000 - 2,000 rpm    | 2.0              | 0.2          | 0.5         |
+----------------------+------------------+--------------+-------------+
| \> 2,000 rpm         | 1.0              | 0.2          | 1.0         |
+----------------------+------------------+--------------+-------------+
| VSD Driven Motors:   |                  |              |             |
+----------------------+------------------+--------------+-------------+
| 1,000 - 2,000 rpm    | 2.0              | 0.2          | 0.5\*       |
+----------------------+------------------+--------------+-------------+
| \> 2,000 rpm         | 1.0              | 0.2          | 1.0\*       |
+----------------------+------------------+--------------+-------------+
| Generators           | 2.0              | 0.2          | 0.5         |
+----------------------+------------------+--------------+-------------+
| Centrifugal Fans     |                  |              |             |
+----------------------+------------------+--------------+-------------+
| \< 600 rpm           | 4.0              | 0.3          | 0.5         |
+----------------------+------------------+--------------+-------------+
| 600-1,000 rpm        | 3.0              | 0.3          | 1.0         |
+----------------------+------------------+--------------+-------------+
| 1,000-2,000 rpm      | 2.0              | 0.3          | 1.5         |
+----------------------+------------------+--------------+-------------+
| \> 2,000 rpm         | 1.0              | 0.3          | 2.0         |
+----------------------+------------------+--------------+-------------+
| Vaneaxial Fans       | 1.0              | 0.2          | 0.5         |
+----------------------+------------------+--------------+-------------+
| Blowers              | 1.0              | 0.3          | 0.5         |
+----------------------+------------------+--------------+-------------+
| Pumps                |                  |              |             |
+----------------------+------------------+--------------+-------------+
| 1800 rpm             | 2.0              | 0.2          | 0.5         |
+----------------------+------------------+--------------+-------------+
| 3600 rpm             | 1.0              | 0.2          | 1.0         |
+----------------------+------------------+--------------+-------------+
| Centrifugal          | 1.0              | 0.2          | 3.0         |
| Compressors          |                  |              |             |
+----------------------+------------------+--------------+-------------+
| Cooling Tower        | 3.0              | 0.4          | 2.0         |
| Gearboxes            |                  |              |             |
+----------------------+------------------+--------------+-------------+
| Reciprocating        | 5.0              | 1.0          | 10.0        |
| Engines              |                  |              |             |
|                      |                  |              |             |
| Gas or Diesel        |                  |              |             |
+----------------------+------------------+--------------+-------------+
| Turbines             | 1.0              | 0.2          | 0.5         |
+----------------------+------------------+--------------+-------------+
| Gearboxes            | 1.0              | 0.4          | 2.0         |
+----------------------+------------------+--------------+-------------+
| Twin Screw           | 1.0              | 1.0          | 15.0        |
| Compressors          |                  |              |             |
+----------------------+------------------+--------------+-------------+

> \* High reading is acceptable if due to electronic noise as determined
> by adjusting vibration analyzer to view time waveform. Equipment is
> non-compliant if high reading is due to bearing shock pulse.

B. Displacement measurements at operating speeds shall not exceed values
in Table 1, or reduced values if equipment is mounted on inertia block.
Values in Table 1, multiplied by displacement ratio will give maximum
allowable peak-to-peak displacements for equipment on inertia blocks.

> [1]{.underline}

Displacement Ratio = ((MB/M) + 1) where:

M = Supported equipment and fluid weight

MB = Inertia base weight

C. Machines driven by reciprocating engines, such as pumps or
generators, shall only be required to pass higher limits of
reciprocating engines.

. Non-Compliance: Equipment that does not comply with specified
vibration tolerances shall be corrected at manufacturer\'s expense.
Retest equipment and submit measurement results report in accordance
with requirements of following article.

## 3.04 VIBRATIONS MEASUREMENT REPORT

A. Submit written report that includes the following:

1\. Description of instruments used, their last calibration date, and
calibration method.

2\. Actual vibration measurements and rotating speed at each point in
tabular form. Table 2 is a sample report.

3\. State whether each machine passes or fails based upon vibration
limits listed in Table 1. Analysis of defective condition and
recommendations for corrective action are optional.

4\. See Table 2 for sample report.

B. Vibration Spectrum Plots: Include with written report minimum of
plots for each machine (in velocity units); one plot for driver machine
and another for driven machine.

For machines that pass, choice of which point to plot is at discretion
of analyst. Plots are intended to serve as evidence of passing, and as
baseline data for future analysis.

> **TABLE 2**
>
> **Sample Vibration Report**

+--------------+----------+-----------+-----------+-----------+------+
| *            | **Lo     | Balance   | Overall   | Overall   | **Pa |
| *Equipment** | cation** | Dis       | Velocity  | Acc       | ss** |
|              |          | placement |           | eleration |      |
|              |          |           | (in/sec   |           | **   |
|              |          | (mil,     | Peak      | (*g*,     | or** |
|              |          | P-P)      |           | Peak      |      |
|              |          |           | 10-10,000 |           | **Fa |
|              |          |           | Hz)       | 0 - 5,000 | il** |
|              |          |           |           | Hz)       |      |
+--------------+----------+-----------+-----------+-----------+------+
| MAU-1        | Ho       | 1.2       | 0.09      | 0.8       | Pass |
|              | rizontal |           |           |           |      |
| Opposite     |          | 0.9       | 0.12      | 0.7       |      |
| Drive End    | Vertical |           |           |           |      |
| Bearing      |          | 0.4       | 0.08      | 0.8       |      |
|              | Axial    |           |           |           |      |
| 1,200 rpm    |          |           |           |           |      |
+--------------+----------+-----------+-----------+-----------+------+
| Drive End    | Ho       | 1.1       | 0.13      | 0.9       |      |
|              | rizontal |           |           |           |      |
| Bearing      |          | 0.8       | 0.15      | 1.0       |      |
|              | Vertical |           |           |           |      |
| 1,200 rpm    |          | 0.6       | 0.10      | 0.9       |      |
|              | Axial    |           |           |           |      |
+--------------+----------+-----------+-----------+-----------+------+
| Motor Drive  | Ho       | 0.9       | 0.10      | 0.2       | Pass |
| End          | rizontal |           |           |           |      |
|              |          | 0.7       | 0.12      | 0.3       |      |
| 1,770 rpm    | Vertical |           |           |           |      |
|              |          | 0.5       | 0.09      | 0.1       |      |
|              | Axial    |           |           |           |      |
+--------------+----------+-----------+-----------+-----------+------+
| Opposite     | Ho       | 1.0       | 0.09      | 0.2       |      |
|              | rizontal |           |           |           |      |
| Drive End    |          | 0.8       | 0.11      | 0.15      |      |
|              | Vertical |           |           |           |      |
| 1,770 rpm    |          | 0.2       | 0.09      | 0.11      |      |
|              | Axial    |           |           |           |      |
+--------------+----------+-----------+-----------+-----------+------+

## 3.05 RESONANCE

A. Resonating components on machines or other supplied equipment, such
as pipes, panels, or ducts, are equipment flaws. Contractor shall bear
full burden of stiffening components or other corrective action, until
vibration measurements at bearings pass balance limits listed in Table
1.

B. If equipment vibration testing failures are related to foundation or
building resonance, Contractor shall demonstrate this basis to SDR. SDR
shall do one of the following:

1.  Accept the vibration.

2.  Require additional corrective work on Contractor's part to
    compensate, such as better balancing or alignment, or softer
    springs.

3.  Move the machine.

4.  Stiffen the structure.

END OF SECTION