Engineering and Testing

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 :

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.

Noise surveys at residences: starting point & arrival point of noise control initiative

Vibrator exciting paper machine structure for modal analysis and natural frequencies

Intensity probe measures the noise of a machine component in the presence of other noises

Simulation of dispersion and chimney plume

Recording noise of military aircraft in the forest

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

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!

Coast Guard Icebreaker Structural Vibration

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.