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My First Javascript Online Calculator – Instrument Air and Compressor Sizing

For a long time, I want to post something more advance in this blog. I always want this blog like or I want to make online calculator just like did.

Due to my limitations, at this point I cannot create online calculator. To compensate that, I tried to make useful spreadsheet.

But, today I did it! I made my first online calculator, which is instrument air sizing calculator. Please click this link to access to instrument air and air compressor online calculator. I hope you find it useful.

It is better for you to check two of previous post related with the calculator. Calculation basis used in this calculator is based on those two post.

Read Sizing of Compressor and Instrument Air Capacity

Read Spreadsheet of Air Compressor and Air Dryer Calculation


I already replaced spreadsheet attached in this post : Spreadsheet of Air Compressor and Air Dryer Calculation. So you can trace how the calculation works.


Fire Water Pump Capacity Calculation Part 1 – Fire Zones Determination

Process safety and pressure relieving and depressuring system are two areas that I want to master. Since the topic is quite big, in this post I want to share you what I learnt about fire water pump capacity calculation, specifically how to determine fire zones.

Fire water pump capacity calculation begins with fire zones determination. The whole pictures of fire water pump capacity calculation is expressed in figure below.

Fire water pump capacity calculation
Fire water pump capacity calculation

To determine fire water pump capacity, we can say we determine fire water demandMaximum fire water demand is summation of fire water required for fixed system (water spray, foam, sprinkler) and fire water required for manual fire fighting equipment (fire hydrant, fire monitor, and hose reel). Read More

Cooling Tower Makeup Water Calculation with Example

It’s been a while since the last time I write an article about utility system. In this post I want to share you how to calculate cooling tower makeup water.

Cooling tower must be made up because the water level decrease by the time during operation. There are aspect that contribute to calculation of cooling tower makeup water. Those are:

  • Evaporation loss
  • Drift loss
  • Blow down

Total cooling water makeup water requirement = evaporation loss + drift loss + blow down.

Let’s take a look one by one how to calculate each component.

Evaporation Loss

Evaporation loss is loss of water due to evaporation. It is calculated by this equation:

Evaporation loss = 0.00085 Wc (T1-T2)

Read More

Water treatment plant balance

Water Treatment Plant Capacity Calculation

In this post, I want to share you how to calculate water treatment plant capacity. I used this term to avoid misunderstanding.

  • Raw water is untreated water coming from water source, such as from wellwater, river, or seawater
  • Utility water is raw water which has been treated and used in plant, such as for personal hygiene (flushing), utility station, cooling tower make up
  • Potable water is sufficiently high quality water which is provided for drinking, cooking, laundry, and safety shower/eye wash
  • Demineralized water is treated water which is usually used as chemical dilution of MDEA or boiler feed water

Water treatment plant capacity calculation begins with demin water demand, potable water demand, utility water demand, and the last is raw water demand. Read More

Spreadsheet of Air Compressor and Air Dryer Calculation

In previous post, I shared about how to calculate capacity of air compressor and air dryer. In this post, I want to share you spreadsheet of the calculation. I made the spreadsheet simple so it can be used easily. You just need to input:

  • Quantity of shutdown valve (SDV)
  • Quantity of control valve (CV)
  • Number of utility station/utility connection
  • Capacity of nitrogen generator

In this spreadsheet, I assume to use dessicant type air dryer, so that you also need to input air loss during regeneration.

This is the screen shoot of example.

Air compressor and air dryer calculation spreadsheet
Air compressor and air dryer calculation spreadsheet

At the beginning, I planned to create online calculator. But I thought it will be difficult for me to prepare it and it also takes time if I prepare it by myself. I hope this spreadsheet is useful!

Compressor calculator

[button style=”btn-default btn-sm” icon=”glyphicon glyphicon-save” align=”left” iconcolor=”#4285bf” type=”link” target=”false” title=”Download Compressor Calculator” link=”″]

Nitrogen vaporizing package

Nitrogen Gas Supply System

It is quite some time I don’t write about utility system. In this post I want to share you some basic knowledge of nitrogen supply system. In December 2015, I prepared several training presentation about nitrogen supply system when I was working in this company. I think it is a good idea to share some of them.

Nitrogen is used for purging activity and blanketing due to its unreacted feature.

Nitrogen is used at different application, depend on its application.

Required nitrogen purity based on its application

Required nitrogen purity based on its application

Read More

Why do we need to make complete technical bid tabulation, requisition, or data sheet?

Now I undestand. People said experience is the best teacher. I think that’s true.

I have already follow procurement of several equipment package since the beginning. I compared my preparation and others (especially preparation of engineers from our head company). My preparation was way way incomplete. I felt the effect right now.

One of my colleague asked me if the internal of pressure vessel in water treatment plant will be spark tested or not. The purpose of spark testing is to determine if there are leaks in the rubber lining and identify the locations. It is a mandatory test in rubber lining tanks.

So, what is the problem? The problem is, for any reason, the appointed vendor cannot perform the test. They just give us the guarantee that there will be no leaks in the lining.

I have googled and found that some vendors perform pre- and post-cure inspection for rubber linings. I got to understand that the test was very important.

Back to the topic. I wish I could turn back time and wrote on my technical bid tabulation and requisition, and data sheet about the point. I did not have spend time to focus in such details. That’s something which is not our concern at the beginning and at the last it became a problem.

Lesson learnt: be detail in making technical bid tabulation. Consider many factors. Ask your colleague or somone who has more experience than you. 

Discussing about Fire Extinguisher with Vendors

Yesterday I got a quite tough and long discussion with one of fire extinguisher product vendor. I learned that I need to define what I really want, what scope of supply is, and what scope of works is. The discussion became very unefficient at the beginning because of those issues. My action was late so that I could not control the discussion. Fortunately, it was clear at the end.

I have created material take off for fire extinguisher and other related products, such as hose reel, potable fire extinguisher, manual alarm pull station, smoke detector, hydrant pillar, hydrant box, siamese connection, and water spray for the tanks. However, there were several issues that has not been addressed. Honestly, the discussion broadened my knowledge because the vendor has a lot of experience (I think). In this post, I want to share to you some of the points. Read More

Water Chiller Inspection: My First Experience

Today, the project manager our EPC project asked me to participate in water chiller inspection in Cileungsi, Bogor, Indonesia. It was my first time. So, I felt a bit excited as well as confused. On that inspection, my role was to inspect the equipment and the technical aspects. I actually did not have any idea about the equipment, except the function.

Simply, we can say water chiller is a refrigeration device. It is used to cool a process fluid. A chiller will use either a vapor compression or absorption cycle to cool.

Type of Industrial Chiller

Figure blow shows type of industrial chiller.


Component of Chiller

The basic component of chiller are compressor, evaporator, condenser, and thermostatic expansion valve.

Wastewater Treatment System

A few weeks ago I got a discussion about wastewater treatment system in our proposed plant. I discussed with one of my colleague. He said, “Let the nature works! Let it process the wastewater by itself”. It sounds weird at the first time. But he’s right and he’s a bit wrong.

He’s right because the natural water in streams, rivers, lakes, and reservoir have a natural waste assimilative capacity to remove solids, organic matter, even toxic chemicals in wastewater. He’s a bit wrong because the process takes a really long time. That’s why we need wastewater treatment system to make it quick (read more in Water and Wastewater Calculation Manual). Read More