Dear Friends/Senior,

I have a doubt in insulated piping and pipeline. Normally Pipes are insulated to maintain the inside medium temperature of pipe and personnal protection. Based on the purpose, temperature & fluid condition the insulations are classified into Hot Insulation, Personal protection Insulation, Cold Insulation, Anti-sweat insulation, Acoustic insulation, Heat tracing insulation and etcetra.

My doubt is,

1. When a pipe is completely insulated, it has no contact with atmospheric temperature (Ambient temp.) so the fluid temperature could be maintained, as well as pipe has also no contact with atmospheric temperature so its has the fluid temperature. Formula says whenever there is a change in temperature, change in length occurs (DeltaL = e * L) Where, e-Coefficient of thermal expansion/contraction between 70 deg. F to pipe temperature, in/100ft deg. F (ASME B31.3).

2. As per the above formula insulated pipe has no change in temperature. So will it expand or contract during operating case. If it does kindly explain me how?

3. For insulated pipe is there any special consideration for ambient temperature in the analysis?

Example problem:

Pipe dia = 30”,
Insulatation = Aerofoam,
Insulation Thick = 40 mm,
Medium = Chilled water,
Temperature(1) = 5 deg C, Temperature(2) = 100 deg C,
Ambient Temperature = 40 deg C.
Length = 100 m,

For the above temperature 1 & 2 cases the pipe will contract/expand or not?

Please clear my doubt.