Do duct silencers and sound attenuators have airflow direction?

Many sound attenuators are directional. Match the airflow arrow/submittal orientation before final connection so the baffles do not create extra pressure drop or noise.

['A sound attenuator can look symmetrical from the outside but still have a required airflow direction because of the internal baffle shape.', 'Check the airflow arrow, tag, submittal, and branch direction. If it is reversed, hold final connection, support it safely, and rotate or reinstall it before startup/TAB. Do not assume it is fine because both flanges bolt up.']

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