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Noise, Vibration & AIRFLOW

Silentec is an established leader in noise and gas venting testing and simulation. Its engineers often act as expert witnesses in litigation before municipal, superior or federal courts, as well as in public hearings on the environment or occupational health and safety. municipal, superior or federal courts, as well as during public hearings on the environment or occupational health and safety. Among the techniques used :

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  • Sampling of environmental noise and infrasound.

  • Wall/ceiling sound insulation measures (STC, IIC).

  • Reverberation time, absorption and room echoes.

  • Natural frequencies & acoustic & vibratory modes of rooms, machines and structures.

  • Hot gas exhaust: Velocity profile, pressure loss, noise.

  • Identify sources by intensity, correlation and coherence.

Gas FLOW

Silentec carries out aero-acoustic tests on scale models, to optimise the design of chimneys and ducts fitted with silencers, guides and other gas exhaust devices.

 

In addition, Silentec carries out full-scale laboratory tests as well as field tests to confirm aero-acoustic performance.

 

These activities ensure that the performance required for gas exhaust systems is met, and also to achieve energy savings.

AIRCRAFT & ENVIRONMENTAL NOISE

Silentec has assessed the environmental noise impact of fighter-bomber flights from Canadian Forces Bases CFB-Goose Bay, Labrador and CFB-Bagottville, Quebec. Noise was sampled during overflights as low as 100 feet from the ground. It was quantified in terms of Ldn, detectability and bursts. The aim was to assess the nuisance to humans, interference with sleep and the risk of accidents. For the Caribou, it is the risk of escape affecting energy reserves as well as predation.

SHIPS AND RESONANCE DAMPING

Structural Vibration of Coast Guard Icebreakers

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In one speed range of the Des Groseillers icebreaker, there were loud noises and vibrations from the structure. The situation was worrying.

 

Silentec has carried out tests at sea. The propulsion system is not to blame. Tests and modal analysis of the structure identified a vibration amplification of 100 times, caused by a natural frequency of the structure.

 

Silentec has designed and applied a viscoelastic damping treatment to the faulty part of the structure. Problem solved!

MOTORBIKES WITH ILLEGAL MODIFIED MUFFLERS

Several municipalities have used Silentec to assist them with complaints alleging excessive noise from motorbikes with modified silencers. With the help of motorcycle officers, the noise of a Harley-Davidson with various silencers was measured on a motor vehicle test track. Silencers were cut off and inspected. As an expert witness in the proceedings, Silentec used these results to prove that several of the silencers used were illegal.

QUALITY CONTROL

Manufacturing Quality

Silentec practices quality control according to the following principles:

Rigorous: after training individuals, negligence is not tolerated. QC managers report directly to the president.

Simple: to ensure that the most important things are understood and done. Customers' special needs may also be taken into account.

Silentec uses ASME or CWB certified workshops as required, while applying the following tools:

  • MITP: Test, Inspection and Manufacturing Plan, which lists the stages in the manufacturing and inspection process, with places for the signatures of the inspectors and managers. It is accompanied by supporting documents namely:

    • Certificate of Origin of the material 

    • Dimensional control drawings in accordance with specification 

    • Non-destructive Test Reports, in accordance with specifications. This includes ultrasonic and other weld inspections by Silentec personnel. 

    • NCR (Non-Conformance Report) which documents a change in manufacture compared with the drawings or specifications, with approval or action required 

    • WPQ (Welding Procedure Qualification) 

    • WCR (Welder Certification Report) 

    • CQ Paint 

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