Vibration Isolation – Good, Bad & Ugly 29th October 2013

Matthew Stead

Director

Note this presentation includes extracts from the ASHRAE Fundamentals and Applications Handbooks

AIRAH - Vibration Isolation The Good

•! Theory of vibration isolation •! Why is vibration an issue? •! Practical standards •! Design guides The Bad •! Poor installation •! Poor selection The Ugly •! What goes wrong? •! What does wrong look like? •! How to fix problems •! Don’t get it wrong in the first place.

Scale

Sensitive Equipment

Isolator Types

Isolator Types

Fundamentals

Fundamentals

Fundamentals

Isolation Efficiency

Units

•! Displacement (m) •! Velocity (m/s) •! Acceleration (g, m/s2) •! dB

•! Frequency (Hz) •! Narrowband •! 1/3rd octave band

•! Average (rms) •! Peak •! Peak-to-peak

Units

•! Displacement (m) •! Velocity (m/s) •! Acceleration (g, m/s2) •! dB

•! Frequency (Hz) •! Narrowband •! 1/3rd octave band

•! Average (rms) •! Peak •! Peak-to-peak

Criteria

Building Vibration Design

Response Transmission

(Isolation) Source

•! Structural stiffness and natural frequency key to response

•! Mechanical plant vibration depends on isolation, run speed, structure, distance & balance.

Source Equipment Balancing

Design

Design

Isolation Efficiency

Design Standards ASHRAE

Design Standards ASHRAE

Isolator Types

Isolator Types

Isolator Types

Isolator Types

Isolator Types

Isolator Types

Isolator Types

AIRAH - Vibration Isolation The Good

•! Theory of vibration isolation •! Why is vibration an issue? •! Practical standards •! Design guides The Bad •! Poor installation •! Poor selection The Ugly •! What goes wrong? •! What does wrong look like? •! How to fix problems •! Don’t get it wrong in the first place.

The Bad - Poor Installation / Poor Selection •! Poor Specifications

•! Poor Design •! Lack or training (engineers, owners and

installers)

AIRAH - Vibration Isolation The Good

•! Theory of vibration isolation •! Why is vibration an issue? •! Practical standards •! Design guides The Bad •! Poor installation •! Poor selection The Ugly •! What goes wrong? •! What does wrong look like? •! How to fix problems •! Don’t get it wrong in the first place.

Isolator Types

Isolator Types

Isolator Types

Isolator Types

Isolator Types

Isolator Types

Isolator Types

Isolator Types

Isolator Types

Isolator Types

How to fix problems Don’t get it wrong in the first place.

Fix – time consuming, expensive, source vs. path. Prevention: •! Poor Specifications •! Poor Design •! Lack or Training (engineers, owners

and installers)

How to fix problems Don’t get it wrong in the first place.

Prevention: •! Poor Specifications •! Poor Design •! Lack or Training (engineers, owners

and installers) Specifications -! Refer to ASHRAE at a minimum -! Require selection based on actual

loading -! Specify inertia bases as required

Design -! ASHRAE normally acceptable -! NEBB Sound and Vibration Design

& Analysis -! Detailed finite element

Key points

•! Use ASHRAE as a starting point (coordinate specifications with ASHRAE)

•! Design isolation where critical •! Inspect (hard to check isolation efficiency) •! Test (if necessary) •! Teach contractors – springs ain’t springs!

Thanks

Adelaide p+61 8 8155 5888 97 Carrington Street Adelaide SA 5000

Melbourne p+61 3 9020 3888 Level 4, 10 Yarra Street South Yarra VIC 3141

Sydney p+61 2 8355 4888 Level 7, 657 Pacific Hwy St Leonards NSW 2065

Brisbane p+61 7 3088 2888 Level 2, 123 Charlotte Street Brisbane QLD 4000

Thanks

Adelaidep+61 8 8155 588897 Carrington StreetAdelaide SA 5000

Melbournep+61 3 9020 3888Level 4, 10 Yarra StreetSouth Yarra VIC 3141

Thanks

Adelaidep+61 8 8155 588897 Carrington StreetAdelaide SA 5000

p+61 3 9020 3888Level 4, 10 Yarra StreetSouth Yarra VIC 3141

Matthew Stead Deb James Tom Evans Jon Cooper Vahid Alamshah

Questions