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Pipe wall thickness chart-3

Pipe Wall Thickness Chart

Pipe wall thickness chart is a must-have item for me as process engineer. I usually use it when I have to size pipe, do hydraulic analysis, etc. Information I need from the chart are mostly outside diameter and inside diameter of particular pipe size.

In this post I want to share you pipe wall thickness chart based on ASME B36.19M-2004 Stainless Steel Pipe.

In this chart you can extract data of

  • Outside diameter and wall thickness in inch and mm
  • Pipe size is expressed in NPS (Nominal Pipe Schedule) and DN (Diametre Nominal)
  • Weight in pound per linear foot or kilogram per meter

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Fail-safe position

Fail-Safe Position Selection of Control Valve

In designing a processing facility, we usually use control valve to manipulates the temperature, pressure, level, or fluid flow rate in process system. The selection of control valve, which is air-to-open or air-to-close, is base on safety consideration. In case of power loss or air failure , control valve should move in safe position (fail-safe).

Fail Position

Fail position is the term used to describe how control valve will react when there is loss of power. I read there are three different fail positions. Read More

Pipe Size Selection and Several Criteria of Pipe Size

Someone in my office asked me if there is a criteria for pipe size selection, in other words, pipe sizing criteria. One basic document that every process engineer produce in the beginning of engineering stage is process design basisIn the document, pipe size criteria shall be stated clearly.

I have involved in at least two engineering projects. Those two projects have different pipe size criteria. Which one is correct? Read More

Reciprocating Pump P&ID Configuration

Reciprocating pump is a class of positive displacement pump which includes piston pump, plunger pump, and diaphragm pump. It is often used where a relatively small quantity of liquid to be handled and where delivery pressure is quite large. Priming is not required because it is positive displacement pump. Reciprocating pumps have lower efficiency compared to centrifugal pump.

API 674 – Positive Displacement Pump – Reciprocating covers minimum requirements for reciprocating positive displacement pumps for refinery application. The standard also covers piping and instrumentation required for the pump. Read More

Hydraulic Pump Calculation

Yesterday I just finished doing hydraulic pump calculation for one of a project in my company. The purpose of the calculation was to determine suction pressure, discharge pressure, and pump differential head.

Pump calculation procedure is very simple.

First, you need to define pump operation condition. It includes fluid temperature, fluid specific gravity, fluid viscosity, pump normal capacity and design capacity.

Second, check your Piping and Instrumentation Diagram (P&ID) carefully. In this step you need to calculate pressure drop due to pipe line and fittings in the suction and discharge of pump. You need to list fittings and calculate pressure loss due to the fittings.

Total suction head = line loss + loss due to accessories + suction head

Do the same thing as for discharge head.

Differential head is calculated by this formula

Differential head = total discharge head – total suction head. 

 

Understanding Terms in Piping System Part 1

You always need to find a bright side of a simple task. For example, copy, paste, and modify piping material specification, specification for coating and wrapping, and piping design. Yesterday I did this! At the first time I thought this was a very ridiculuous task yet unimportant. I’ve ever seen a drafter did this. But I found a bright side of this task which is a chance to learn. 

My objective is very simple. I want to understand what other people are talking about, when piping is their topic. I want to undestand the terms and imagine what they are looked like. That’s all. I think this is a good step to learn about piping.

Piping system has a lot of terms. So, it is impossible to write and describe all of them. In this post I want to share a brief explanation about piping system. As long as I understand them, it’s oke 🙂 Read More

Where to install pressure gauge at pump discharge line

Yesterday I had enough time to increase my basic knowledge in chemical engineering because I had finished my works. Then, I stumbled upon this link and started to think about my piping and instrumentation diagram. I realized I had make a fundamental mistakes. I felt useless.

I am writing this post so that I will remember my mistakes and never try to do it again. Hope you find it useful.

Remember everyone! Pressure gauge shall be installed after pump discharge nozzle and before check valve. The consequence is if you have two pumps (one is running and another is stand by, then you have to install two pressure gauge). The reason is:

  • To show actual pump discharge pressure. If you install pressure gauge after check valve, the value of discharge pressure won’t be actual due to pressure loss of check valve
  • In the case of check valve failure, pressure gauge will show actual discharge pressure. If the pump has problem, pressure gauge will show pressure value lower than usual

Typical Configuration of Pump in Piping and Instrumentation Diagram (P&ID)

Since I have involved in the current project, which is EPC project, I always want to make some short writing and simple guideline to create piping and instrumentation diagram (P&ID) for several equipments, such as pump, tank, vessel, compressor, and so on. This post will be my first post on simple guideline related to configuration of pump in piping and instrumentation diagram.

Typical Configuration of Pump on PID
Typical Configuration of Pump on PID

Figure above reprsents typical piping and instrumentation diagram of pump. Pump should have:

  1. Pump Symbol. Make sure you use proper pump symbol. As for example above, I use centrifugal pump.  Check your P&ID legend
  2. All the nozzles should be correctly represented with size and flanges. Generally, the suction and discharge nozzles on the pump are smaller than suction and discharge line sizes. Appropriate reducer / expander to be clearly indicated in such cases.
  3. Strainer. In the example above, I install Y-strainer. The strainer is used to separate debris from the liquid
  4. Check valve. Check valve shall be installed to prevent liquid flow reversal with the succession of pumping
  5. Globe valve. Globe valve installed at discharge line to regulate the flow of liquid
  6. Pressure gauges are normally to be provided on suction and discharge  line
  7. Inlet and outlet lines are the next to be drawn up. Line number, material class, size, pressure rating, etc. is to be correctly assigned to each of the lines.
  8. Drains and vents to be provided on the suction / discharge lines

Source.

Creating Piping and Instrumentation Diagram: My Real Experiences

Example of P&ID
http://www.engineeringtoolbox.com/p-id-piping-instrumentation-diagram-d_466.html

As already described in previous posts (such as here and here), I was involved in EPC project. Creating piping and instrumentation diagram (P&ID) is one of my responsibility. I think P&ID is a collection of information and collaboration of every discipline, such as process, mechanical, electrical, and instrumentation. Once I think creating P&ID is easy enough, but I change my mind then. It is not.

I revised my P&ID (water treatment plant, fuel supply system, and wastewater treatment plant) several times. I am not quite sure if I am a kind of diligent person, but I am sure creating “perfect P&ID” requires a lot of works and patience. I sometimes think there’s nothing wrong with my P&ID. However, if you let someone, for example your colleagues, your boss, or someone with more experiences than you to check your P&ID, you will laugh at yourself. It happened to me. My P&ID was far from perfect. I understand now. Perfect P&ID requires continuous improvement. Read More

How to Calculate Jockey Pump Capacity in Fire Fighting System

Main_fire_pumps_with_Jockey
http://en.wikipedia.org/wiki/Fire_pump

About two days ago, my colleague asked me about inconsistency in our design basis of fire fighting system of our on-going project. In our design basis, we stated that the capacity of jockey pump is 50 gpm (the capacity of main fire pump is 500 gpm for electric motor fire fighting and diesel engine fire fighting, respectively). But vendor who supply fire fighting package stated that they will supply jockey pump with the capacity of 25 gpm. It would be a problem if the Construction Management (the one who monitors and review the product of the project) notices this. The question that will be come up is are you sure the capacity of jockey pump (which is 25 gpm) is enough in case there is a fire? The question rises in my mind is

How to calculate jockey pump capacity in fire fighting system? Read More