Expansion joints in a pipe rack 1

[sdz]

I am designing an external pipe rack. If I have two braced bays in the length how far apart can they be before I need to put an expansion joint between them to relieve stresses from thermal expansion? Say there is a 50 degree temperature change from installed condition.

 

[MiketheEngineer]

My book ways about .033 ft(about .400 inches) per 100' of length at 50F. I am sure it will see more than 50F swing - proably more like 120F from summer baking and winter freezing. Don't forget that the pipes may put out a lot of heat and where are those expansion joints or do they use sliding corners...

At 120F about .078'(about 1'') per 100' feet of length.

 

[BAretired]

Why not bring your braced bays closer together? You could move each brace set one bay closer to the middle.

BA

 

[sdz]

Clarifications
1. That's 50 deg C, about 90 deg F
2. Due to access the braced bays can't be moved closer together.
3. Assume there are an indeterminate number of unbraced bays between the ends.

So how far can I go before thermal expansion becomes a design issue?

 

[westheimer1234]

typical brace bay is every 5 bent frames about 100ft to max of 150 ft
anyhow put your brace frame every 5 bent frames if possible.

also your brace bay is not usual for piperacks.
try inverted chevron from ground to top

 

[westheimer1234]

see attached...

 

[BAretired]

westheimer1234 has come up with a good solution.

BA

 

[sdz]

Thanks westheimer1234,

How many intermediate bays can you have without an expansion joint?

 

[westheimer1234]

it's not how many, it's how long a piperack before you put expansion joint.
maximum 150 ft. but usually we use 100 ft.

for every 100 ft you need 1 brace bay just like my drawing and is usually located at the center if possible but not necessarily.