How to determine the thickness of the insulation layer

It relates to your surrounding environment, insulation materials, etc.; you may refer to the Design Code for Heating, Ventilation and Air Conditioning (2003 edition)

It is also mentioned in the Process Piping Installation Design Manual

There are calculation formulas in the chemical process design manual. Calculations can be done based on factors such as your climate temperature and the thermal conductivity of the materials used

You can check the book on power piping manuals; it contains all the calculations related to pipes. Here is a calculation formula for you. The formulas are as follows: 1. (D0/2) ln(D0/Di) = A1√(λτfn(t-ta)/(PiS)) – λ/α; 2. δ = (D0 – Di)/2. The values for each parameter are as follows: D0 is the outer diameter, and Di is the inner diameter ； A1=1.9ⅹ10-3 λ can be obtained from a table ； Operating time per year: generally, 8000 hours is assumed for year-round operation, while 3000 hours is assumed for the heating period during heating season; the annual operating time and the heating period can also be determined based on actual conditions ； fn heat price ； ta lookup table ； Pi = P1 + (2/D0)P2 (P1 is the unit cost of the insulation layer, P2 is the unit cost of the protective layer) ； S=（（i（1+i）n）/（（1+i）n-1）） ； The heat transfer coefficient from the outer surface of the insulation layer to the atmosphere is generally taken as α=11.63 W/(m²°C) in calculations related to the optimal thickness and heat loss. When verifying the surface temperature of the insulation structure, α=1.163(6+3√w) W/(m²°C) is usually used, where w represents the wind speed. Actually, there is another very simple method: just check the insulation thickness table, as the information is listed there.

The simplest way is the second volume of Principles of Chemical Engineering, but it doesn’t contain property data

Calculations should be carried out based on the process requirements; formulas can be found in chemical process design manuals. The concept of insulation is broad, and what’s important is to know what fluid is present and what its purpose is. If cooling is required, then it serves to prevent overheating, and the thickness of the insulation will vary accordingly.

In the design calculation of the insulation layer thickness, how is the theoretically calculated thickness of the insulation layer converted into a practical thickness using correction factors? There are generally two feasible approaches: 1) Multiply the theoretical value of the material’s thermal conductivity by one or several correction factors to obtain the designed thermal conductivity value for that material under different operating conditions, and then calculate the practical thickness required for the insulation layer based on the allowable heat dissipation values specified in GB4272. 2) After calculating the theoretical thickness of the insulation layer using the heat dissipation method, three sets of theoretical thickness correction coefficients K1, K2, and K3 are formulated comprehensively based on various factors such as the type of insulation material and structure, installation location, environment, and temperature parameters. That is, the comprehensive principle of the so-called correction coefficients

The simplest approach is to consult a table; by knowing the pipe diameter, medium temperature, and the geographical region where the project is located, the corresponding insulation thickness can be found in the pipeline installation design manual for petrochemical industries