What is the PSI definition? Very concise and can be understood by anyone!
If you are a person who often buys iron and steel, or works in the field of pipeline construction.
Surely you will notice that in most specification sheets, manufacturers’ catalogs have the presence of a quantity that is test pressure (in units of psi or in some other brands it is psi). kPa).
So you wonder what PSI is? And why does the manufacturer take it to represent the bearing capacity of its product?
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Because of the documents and articles I read online, the information is very mixed.
Each had their own ideas, and others had a sketchy explanation, insufficient information, and evidence to prove it. People are too specialized, maybe only a few masters and doctors can understand.
Most typical, perhaps the origin of this unit.
So I decided to do this post.
After many days of tinkering in the sea of information, this is what I have learned.
What is PSI?
Summary: “PSI stands for Pounds Per Square Inch, and Psi is one of the units that represent Pressure”.
In the international standard of measurement, 1 PSI = 1 yard of water (27.7 Inches).
- Pressure is said to be absolute (PSIA) if and only if it is measured, without reference to any point other than itself. For example, the measured atmospheric pressure is 14.7 PSIA.
- When the pressure is referenced to the atmosphere, it is called the gauge pressure (PSIG). For example, the pressure of water relative to the air, etc.
What is the meaning of PSI?
Here, we will look at 2 cases, and go into the analysis of both.
- Producer
- End users (investors, contractors, residents, …)
First for pipe manufacturers:
- The PSI index of the standard (the standard for steel pipe production is different for each company: ASTM, BS EN, …) is the basis that manufacturers rely on to produce steel pipes.
- It stipulates how much pressure that steel pipe must withstand to reach the quality supplied to the market. For example, according to ASTM A53, for pipes of class F — butt weld, continuous welding, and Class A, minimum stress of 30 000 PSI must be achieved.
For design and construction contractors and investors.
- The general contractors and investors will rely on the PSI index of the steel pipe to be able to calculate the size selection; type of pipe suitable for construction for your project.
- The inspection units will also be easier to verify the quality of the works; calculate a reasonable construction plan.
>>> Here is a practical example for your reference (note that if you are free, watch it, I’m afraid you guys will get confused).
For example, based on the PSI of steel pipes for water supply construction
d is the specific gravity of the liquid (N/m3), d of water is 997 kg/m³ = 9 970 N/m3
h is the height of the water column (m)
P = 9 970 N/m3 * 30 m * 40 m3/h = 11 964 (kPa) = 1 735 (PSI)
Compare according to section 6.5, standard TCVN4513:1988
The speed of water flowing in the steel pipe supplying domestic water inside the house must not exceed the following values:
In main pipes and risers: from 1.5 to 2 m/s
Apply the following formula to calculate the pipe diameter:
D= Sqrt((4*Q)/(V*3.14))
=> D= Sqrt((4*40)/(2*3600*3.14)) = 0.084 (m) = 84 (mm)
Look up the catalog of SeAH steel pipes. We choose a pipe with size DN80, with an outer diameter of 88.9 (mm), and a thickness of 4.78 mm.
Here are some great reasons to give you the answer.
The reason why countries have to use the same PSI unit to represent pressure
It was not until 1875 that an intergovernmental organization for weighing and measuring was established (abbreviated BIPM). The BIPM organization includes:
- Delegates of the Government of Member States
- Observers from Associations around the world
PSI unit conversion value with other units
- 1 Psi = 6.894,76 Pa
- 1 Psi = 68,948×10−3 Bar
- 1 Psi = 70,307×10−3 at
- 1 Psi = 68,046×10−3 atm
- 1 Psi = 51,715 Torr
A small gift for you for reading this far
Interested readers can click on each link I put below.
- TCVN 4513-1988 – Internal water supply and design standards.
- TCXDVN 33:2006 Water supply – Pipeline network and standard design works.
- QCXDVN 01: 2008/BXD – Vietnam Construction Code – Construction Planning.
Extremely valuable gift compiled by Tiger Steel Document AISI standard steel grade
Maybe what I share here will have shortcomings. So if you think you need to add anything, just call Tiger Steel for corrections!