Hi all:


usually our systems of piping consist in two types of isolation. The external, mineral wool, and internal isolation (Polyurethane, for corrosion).

My question as follow: How income through CAESAR II, while the two insulation??

Thanks in advance

The only reason why CII needs the isolation properties is to correctly calculate the weight of the entire package (fluid + pipe + insulation). Simplest solution is to redefine the fluid density depending on the pipe ID and the actual ID, and to redefine the outside insulation in such a way that it represents the complete package (inside and outside) as far as weight is concerned.

You should however ask yourself what the influence of this is on the complete analysis in comparison with a solution where you simply "forget" the inside insulation.

I pre-assume "Polyurethane" as lining? if yes, you can set "one new" insulation by define a new value of density and "keep the thickness" of insulation by using equation ; W of the new insulation per L pipe = (W of insulation + W of lining) per L pipe. Please be clear regarding to insulation and lining. Correct me if I'm wrong then. If both are insulation you are able also to use that equation, but the new thickness should be the sum of both thickness. It is important in the represent of them for the wind load using considering the surface area due to thickness.

Sorry my system problem...

Samsul:

The mineral wool is outside to the piping, and the lining internal is Polyurethane.

From the viewpoint of the income of signs, do not apply to your reply.

Many thanks & regards,

There is no sign, please read again Corne's posting again very carefully.

The only reason why CII needs the isolation properties is to correctly calculate the weight of the entire package (fluid + pipe + insulation + lining).

Be careful of the thickness for the represent of the wind load as I mentioned.

As "Corne" indicated above, the important thing here is the overall unit weight per length - that must be correct.

Additionally, if your piping is subjected to wind loads, then the outer thickness of insulation is very important - for the determination of the projected area. In this instance, your (outer) thickness is fixed - therefore this is the density value that must be recomputed to include both the inside and outside insulation weights. This also means that the fluid density must be recomputed since will now fill the entire inside of the pipe with fluid.

If wind is not an issue, you can put the entire insulation on the inside of the pipe (with the proper thickness) and just recompute the (combined) density of the insulation. Since the thickness is correct, CAESAR II will properly determine the fluid weight.

Samsul, thanks but according to what commented, I understand that the insulation is taken into account from the standpoint of burdens caused by the weight and those produced by the wind (projected area of the external insulation). However, it is important to distinguish whether insulation is an internal and / or external, from the standpoint of heat transfer, for an assessment of the strength of the material of the pipe taking into account the actual temperature (in operation) to that found the pipe.

The rapporteur of the ongoing CAESAR told us that if we had inner lining, we should enter the thick of it with a negative sign to tell the software that the coating is internal (inside of the pipe).

Thanks in advance

CAESAR II doesn't do anything with heat transfer. You physically still need your inside and outside insulation. However, you can only define one of them in a given CAESAR II model. Therefore you have to combine the densities so that you end up with the correct unit weight per length. The idea is to do the least amount of hand computation, so:

- if you have wind in the picture, you need the insulation on the exterior of the pipe, you'll need a modified insulation and fluid density.

- if wind is not in the picture, you can put the insulation on the inside and you'll only need a modified insulation density.