Busduct's thermal expansion/expansion lengths

[Marby]

Good day!

Is it mandatory to include a thermal expansion box on a 500ft height bldg?

Thank you for your response.

 

[Smart $]

Straight run?

368.244 Expansion Fittings. Flexible or expansion connections
shall be provided in long, straight runs of bus to
allow for temperature expansion or contraction, or where
the busway run crosses building vibration insulation joints.

Note "long, straight runs" is quite ambiguous regarding actual distance.

 

[iwire]

Just a guess here but I imagine the manufacturer will provide guidance on this.

In my limited experiance bus ducts of up to seven floors do not have expansion fittings but are supported by springs on each floor to allow the floor to move relitive to the busduct.

 

[Marby]

thank you so much.

thank you so much.

thank you so much. it helps.