Brief explanation and refreshment of force & moment which generally referred to as load or loading. For pressure vessel or basic structural design for oil & gas, manufacturing or any relevant field for engineers, designers, technicians, or students.

1. LOADING
The what-why-how of understanding basic principle of
loading and “refreshing” basic concept of loads
Slides By:
Syed Amir Syed Omar (Sam)

2. LOADINGS: WHY CALCULATE?
The reason is practically simple, not to overcomplicate things, loadings is
considered to ensure that the material of construction when subjected to
the load does not fail, easy right?
Yes indeed, what to consider and check? For example the structural unit is
made of several material with different stress value at working temperature,
whether ambient, local, or controlled temperature, not to reached it’s yield
strength.
What does that mean? It means what ever loads is to be considered, the
designer/engineer needs to ensure the subjected/calculated load does not
exceed the material yield strength.
Example, you have a material with 200 MPa yield strength, then from the
highest calculated load value you have, let say, 200 kN (200,000 N) with the
subjected area of 20 sq-m, this means the subjected pressure on the load
bearing face is 10 kPa. This means the material/structural steel is capable of
withstanding the 200 kN force.

3. X
Y Y
Z
Two (2) loading to be calculated based
on plane reference:
 Y-X plane
 Y-Z plane
Larger area to be taken for calculation
LOADINGS: THE BODY

4. LOADINGS: WHAT TO CALCULATE?
Loading is any action or movement subjected to a body, hereinafter,
referred as FORCES & MOMENTS
FORCES MOMENT
Sudden force/impact acted
upon plane of a axial or
lateral plane
A point or reference line of
where the body is subjected
to a force

5. LOADINGS: HOW TO CALCULATE?
The basic fundamental of loading being force or moment are as per
following formula
Force, F (Newton, N) = Pressure, P (Pa/N-m-2) x Area, A (m2)
*depending on unit, the calculation may vary
Moment, M (Newton-meter, Nm) = Force, F(N) x Height/Distance (m)
*depending on unit, the calculation may vary
The positive & negative symbols also denotes that the forces and moment
are either subjected to compressive (pushing) or tensile (stretch). This is
determine from source of the load bearing faces
Tensile
Region
Compressive
Region

6. LOADINGS: TYPES OF LOADS
There are various types of loads than be considered during design stage.
The most basic loads are the weight of the unit itself, by default there would
be four (4) different loads:
• Empty Weight Load
• Complete unit assembly without any fluid
• Full Water Weight Load
• Complete unit assembly completely filled with water
• Hydrostatic Test Weight Load
• Complete unit assembly completely filled with water at test
pressure
• Operating Weight Load
• Complete unit assembly completely filled with operating fluid at
operating pressure
Is this all? Not exactly, certain project or client requirement, they would
request that manufacturer to calculated several other loads like
seismic/earthquake, wind, snow, fire blast, transportation, lifting, and etc.

7. LOADINGS: FORMULA
When it comes to which formula shall be used, it depends on the
contractual terms and technical agreement between manufacturer and
purchaser on which codes & standards or engineering practices to be used.
As covered in Slide No. 3 and 4, the most basic formula designer/engineer
can used to “roughly” estimate or calculate the loads is using the force and
moment formula with the provision of required data.
Some purchaser or operator, would require purchaser to refer or used
formula in certain codes, standards or standard practice to calculate this
loads as certain rules require the use of certain coefficient or some require
calculation based on certain condition e.g. normal, high, basic, worse etc.

8. LOADINGS: DIFFICULT?
How difficult? Well depends on the designer/engineer, nothing is made easy
in engineering because if it is, then everyone can simply become an
engineer…got what I’m saying? 
“Practice makes perfect”, the ye ole favorite terms that shall be adapt by any
individual regardless or engineer, designer, doctor, technician, mechanics or
even a cashier.
It does not means you’re not an associate of engineering field then you
shouldn’t care about these loadings, sometimes a carpenter also require
this loadings when they plan to design a house, a barn, or any woodwork
masterpiece.
Sure, there are many software available but the most powerful software
and hardware is pen, paper and calculator 