Duct Attenuators (Imperial)

Our latest collection of Revit families follows on from our work with industry experts. This week we focus on duct attenuators. The collection contains reactive, absorptive and cross talk attenuators for use in both square and round duct. The cross talk attenuators are available in U, Z and L shapes and the inline attenuators have type driven and duct size instance driven versions.

Duct attenuation is a subject highlighted by Ben Drakes work at Rushing Co with many of their attenuators coming from Price Industries. Their use of manufacturer attenuators demonstrated a variety of conflicting approaches out there which can prove cumbersome to use, especially if you need to coordinate using more than one manufacturer.

Conflicting approaches from Manufacturers

Duct attenuators are normally created as a duct accessory family and are set up to break into the duct. This is not the first time we’ve seen manufacturers veer away from industry and Autodesk standards and it can be questioned whether they even know they are doing something wrong. Personally I don't think I’ve ever had the time in coordination to email a manufacturer and tell them the issues, we’re all too busy modelling and pushing out drawings.

Price Industries attenuators have been set up as Mechanical Equipment, which is really meant for something that would create the systems such as the air handling unit. Alone this isn’t the biggest problem, it just means the user has to pay extra attention to object styles and it could conflict with filters or system setups. However, the part type is set as Normal so it doesn't break into ductwork. The connectors are set as Supply Air which means it will conflict with any other system and it will only create supply air systems.

Normally the orientation of the family is left/right, rather than up/down and the use of an instance parameter to drive the half length, which is tied to the named reference plane means that in a project there are two grippies which both increase the length of the attenuator and in both directions of the duct.

Reactive Attenuators

Our collection contains two reactive attenuators from IAC Acoustics and Ruskin. Both attenuators are rectangular with square duct connections. They come in set sizes and lengths from their manufacturers and as such are controlled by a type catalogue with over 60 types. The Ruskin model has slip joint connection method and the IAC Acoustic model is flanged at both end

Absorptive Attenuators

We have five absorptive attenuators which have their width and height set as instance specific, so they are defined by the duct size they are dropped into. From Price Industries, we created their rectangular RL/RM/RH model. The family has four internal types defined by the various lengths.

From Price Industries and Linx Industries we have created their circular absorptive attenuator models. All of these families have eight types defined by the various lengths and are available with standard and extended insulation thicknesses.

Cross Talk Attenuators

Last but not least, the collection also contains three cross talk attenuators (L, U and Z shaped), from manufacturer Price Industries. Cross Talk Silencers are designed to maintain sound transmission ratings in low velocity (below 750 fpm) applications where air is transferred between adjoining spaces.

All of these cross talk attenuators have been built so they can attach to the grille and when the length changes they do NOT move the grille itself. They also rotate about the grille and the width/height will change to suit the grille.

The attenuators also have instance parameters to control collar height, thickness and overall length. Ensuring these families can be modified by the end user to suit any design or construction requirements.

The L & U shaped cross talk attenuator are both designed to be used in in the ceiling void and can connect to a ceiling grille. The U shape has downward and upward facing types so it can be placed manually when the design does not require any grille connection.

Developed in partnership with Ben Drake, BIM Manager at Rushing.

In order to bring you the best Revit content, we continue partnering with industry experts to identify the most relevant and useful products for our collections. Ben Drake is BIM Manager at Rushing, a ‘technology-driven off-site’ construction company based in Seattle.

If you work in a specialised industry and feel like the Revit families available to you are missing the mark please let us know and we’ll see what we can do to help.

Get the Collection

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Collection Content List

1. Two absorptive circular attenuators from Linx Industries.

2. Two absorptive circular attenuators from Price Industries.

3. Absorptive rectangular attenuator from Price Industries.

4. Reactive rectangular attenuator from Ruskin.

5. Reactive rectangular attenuator from IAC Acoustic.

6. Z shaped cross talk attenuator from Price Industries.

7. U shaped cross talk attenuator from Price Industries.

8. L shaped cross talk attenuator from Price Industries.