Manhours Estimation

Almost everything is really tough for the first time even to eat solid foods for a baby. Similarly goes to us as an engineer where something new could be really tough whereby for a experienced engineer could be very fundamental.

Topic I would like to bring into discussion is on manhours estimation for a project based on different disciplines. This is something very subjective where it is done solely based on previous experience. The approach could be different as well depending on supply-demand curve. However previous experience also play a big role when quoting hours based on the fastest track or the most luxurious projects previously done. Experience is properly recorded and developed, it could some database for younger engineers to estimate manhours.

InshaALLAH, god willing, my resolution for 2015 is to develop my own database on hours required based on deliverable or CTR. This is based on my lead and senior engineers experience on typical manhours quoted from previous project. Different leads and senior could be from different organisations and/or different clients. 

Last but not least, manhours estimation definitely will be slashed by project prior submitting the proposal. So, no harm quoting hours as long we are confident enough that we could deliver the project with assigned tasks and time-frame so that the hours quoted will not burst and ultimately the project executed is profitable.

Resume Writing

Hi fellow my blog readers, I’m extremely sorry for the idling time for couple of years in my blog. Inshaa ALLAH, god willing I’ll make busy writing again my blog to share my experience when dealing with projects and issuing related documents for process engineering deliverables in oil and gas industry.

Besides sharing experience on lesson learnt while executing the projects, I may also write about career development for engineers especially for Chemical / Process Engineers. The articles may cover on Board of Engineers, Malaysia (BEM), Institute of Engineer, Malaysia (IEM), Institute of Chemical Engineers, UK (IChemE), and other relevant body. You may see as well about activity in IEM and IChemE which are held on daily, weekly, monthly, annual, and occasion basis.

Very recent activity in Chemical Engineering Technical Division, CETD (IEM) is Design Competition among university students in Malaysia. Besides promoting this event I would say that we committee members still looking for panels to evaluate the reports and judge during final presentation. Kindly have a look on the details and let me know any queries by leaving comment or contact direct the secretariat.

Dilemma Between P&ID and Safe Chart

The due dates for Piping and Instrumentation Diagram, P&ID and Safe Chart always is a conflict personally for me and generally for a project. This is because due date for P&ID is more critical deliverables compared to Safe Chart. However, Safe Chart is a checklist practice to be done on P&ID to evaluate requirement on safety devices/devices. This is developed conjunction with of API RP 14C where clear guidelines are provided where to provide all the safety devices/devices.

With this Safe Chart, we able to identify which equipment need relevant safety devices, Low alarm, Low Low trip, High alarm, High High trip, check valve, etc. This is very crucial because it gives minimum requirement and acts as basis when developing P&IDs. The P&IDs being developed will be based on minimum requirement and at least will have some idea on minimum safety devices to be installed on related equipment before it is used for design review and later for Hazard and Operability (HAZOP).

Development of safe chart should be earlier than P&ID so that most of the safety devices requirement can be captured but producing P&ID earlier than safe chart becomes common practice nowadays. The issue with this practice is that if the design is done for detailed design or EPCC and instrument items are bought during development of safe chart. As highlighted earlier, priority of issuing documents is more weighed to P&ID and sometimes issuance of safe chart could be during IFC/AFD of the P&ID. With this scenario, safe chart might be developed based on existing P&ID and not really based on API RP 14C guideline which sometimes some crucial safety devices might be missing in both P&ID and safe chart.

Safe chart is normally developed based “Safety Analysis Checklist (SAC)” which is available in API RP 14C where give items to be checked such as will pressure safety device (PSH, PSL, and PSV), flow safety device (FSV), level safety devices TSH and TSL), temperature safety device (TSH), and not limited to what only available in this SAC but additional input may be added based on design review and HAZOP. Hence, by applying this checklist, most of the criteria which considered as critical will be captured even before design review or/and HAZOP. However, the dilemma is there in design house consultants where requirement to issue Safe Chart not really consistent among phases of project, among projects, and/or clients/consultants.

Air System

Here is something interesting to discuss on how to design air system in term it's capacity. It's basically on how to determine user's consumption. Users can be continuous users and intermittent users. Continuous users easily can be estimated since these users are consume continuously and no need to consider on oversizing the air system. However, there is some confusion in intermittent users. There are two different approaches in estimating the consumption for these users when designing air compressors. This intermittent users also classified as dynamic users sometimes. The first approach is by putting some weightage to the different users in percentage which will give lower consumption per unit user; it shows that the consumption is not fully utilized all the time. The second approach is by taking three single largest users without multiplying with any weightage. This is something very hard to clarify because of the subjectiveness. Lastly, any comments or criticisms are most welcome for our all understanding improvement.