Chilled Water Piping Suppot/Thermal Expansion contraction

[irfansiddiqui]

Dear All,

I have an HVAC system of 300TR Chiller with 2 pumps(1duty and Stand by, the structure to cool is a steel structure ( a typiccal Laundry Firm) in which i have to hang the duct and piping, I am new to this type of supporting can any one help me out, please refer me to some supporting details on I beams and steel structure.

2. There is no boiler or heating system, means that the water in the pipes will be of 7 Deg Centi to 12 Deg Centigrade, even then consultant has commented to provide way to accommodate the contraction and expansion of pipes, i am unable to understand the comment, what exactly consultant is looking for.?? can any one help ? any suggestions?

 

[EnergyProfessional]

For the operating temperatures you need to consider the extremes inc. space temp when the system is off. Like if that building is at 30°C max and your chilled water temp is 4°C (be safe!) your expansion needs to allow 26°F. I would say assume 40-50°C for expansion.

why don't you ask that consultant what he meant and have him provide the solution?

ASHRAE fundamentals and other sources have methods to allow expansion and to calculate how much expansion to expect.

 

[Drazen]

when system is off, piping temperature will go up from 7 degrees to say 30 degrees or more, depending on what is assumed temperature of uncooled room.

that makes temperature change of 25-30 degrees Celsius. what kind of compensation you need depends on piping run lengths, diameters, load carrying abilities of structure.

i don't understand how would you deal with it if you are not familiar with calculations, design concepts. incapable design can put someone's life in danger. you need professional design help.

 

[irfansiddiqui]

Kindly check the calculation,

regarding details of hangers and support what should i do?

 

[irfansiddiqui]

Kindly also suggest if - Clevis hanger can accommodate for the expansion of 1 inch in whole piping of 3000 inch(250 ft)?

 

[ZDR1985]

There are many ways to accommodate expansion and contraction in piping, but that depends on how the pipes are routed.

There are expansion loops, expansion joints, sliding guide supports, roller supports, etc. Your clevis support can have roller seat too!

 

[irfansiddiqui]

I will go with the clevis support,, thanks ZDR1985.

 

[dbill74]

Irfansiddiqui,
Your consultant is referring to the linear lengthening and shortening of the steel pipe as it is subjected to changing temperatures. As the pipe heats up it will get longer; when colder, shorter. A 10 foot length of pipe will grow to 10'-1" if heated enough.

In a clevis support, the pipe is not fixed to the support and is allowed to "slide" through the support as it expands and contracts.

However, clevis supports by themselves do not prevent problems associated with pipe expansion/contraction. When you have long straight runs of chilled water pipe, you will need to have expansion loops, expansion joints, etc. to reduce the stresses in the pipe as is expands and contracts. Failure to include these features will result in pipe failure.

That said, follow Drazen's advise and get some local professional help.

 

[Drazen]

yes, as dbill74 pointed, clevis hanger is not device to deal with expansion/contraction forces, it just carries weight.

it is fixed point that holds those forces, and expansion compensation devices or pipe loops serve to reduce those forces to manageable level.

you cannot bypass calculation. there are good engineering manuals which provide information of the acceptable extent of self-compensation, i. e. for simpler cases you can find resulting forces in tables and than compare it with your fixed point specs.

ignoring all that is very dangerous business and does not belong to acceptable engineering practice.

 

[ZDR1985]

irfan,

As others have emphasized, in order for the pipe not to break or collapse during contraction and expansion, there should be flexibility along with the pipeline, that is the use of your expansion loops, expansion joints etc.

Your clevis support or whatever support you want that is applicable to your pipe orientation is fine as long as it does not restrict your pipe movement during expansion and contraction (roller, sliding, guide etc.).

Also, there should be fixed points (fixed supports) to divide your pipeline into individual expanding sections.