I have got a report from an existing calculation done in 2002 by CII where I see some uniform loads in x and z directions applying
sporadically. (y is vertical) it could not be either blast load or wind load since the blast load has been mentioned on the drawings differently and the system is not exposed to wind at all. insulation has been modeled as it had to be and to the best of my knowledge, everything looks pretty normal.
I need some second opinions about what those uniform loads could be.

thanks

a

You need to ask this question of the person or persons who created the input. Statements from anyone else would be purely a guess.

The company who made these calculations does not exist anymore in Holland. assuming the person who made them is so co-operative and nice enough to answer the question, it would be impossible to find him/her by just having
his/her initials of JB!

I vote for asking Jack Black first.

However, if you want us to guess, perhaps it would help if you answered the following, or maybe you can answer it yourself with this mindset:

1) Direction of force vs pipe orientation (are these forces axial or perpendicular with respect to the piping orientation)
2) How do the magnitudes of forces compare with:
a) length of pipe
b) cross sectional area of pipe (circular)
c) cross sectional area of side profile of pipe (rectangular)
d) volume of segment of pipe
3) What the pipe is used for, and if there are any unusual properties of the contents?
4) What setting is the pipe in? Is it on some unstable/dynamic platform?
5) Are these uniform loads expressed in force/length or in accelerations?
6) Do you have livestock or wild animals (or very large operators) who like to come lean on the piping when it's cold outside?

Obviously it's all just guesswork - if you can find the actual study, maybe you can find the project basis for design document.