Author: Vikas Khaitan

Weight Tables for Quick Piping Material Estimate

Vikas Khaitan1 Comment

In one of my previous blogs, Quick Piping Material Estimate, I provided indicative benchmark $/kg rates for various carbon steel piping items, and discussed how these rates could be used to quickly estimate piping material costs.

To be able to do that, the estimator would need access to the weight tabulations for various piping items, which I mentioned can be easily obtained from manufacturers of pipes, fittings, flanges and valves.

The file attached below has tabulations of different piping items which I have collected from various manufacturer catalogues. This is a free estimating resource for anybody who wishes to download and use.

Piping Weight Tables (Excel file) – Free Estimating Resource

The weight tables available are for below Carbon Steel piping items:

  • Pipes
  • Fittings
    • 45° Long Radius Elbows
    • 90° Long Radius Elbows
    • Caps
    • Tees
    • Reducers
  • Flanges
    • WN Flanges
    • Blind Flanges
    • Spectacle Blind Flanges
  • Valves
    • Globe Valves
    • Check valves
    • Gate Valves
    • Full Bore Ball Valves
    • Reduced Bore Ball Valves

Weight tabulation of additional piping items can be added to this file if required. Any missing weights for particular sizes can be prorated, from nearby weights, for estimating purposes.

The file also shows how these weight tabulations can be used in conjunction with Excel functions like HLOOKUP and VLOOKUP in order to quickly list out the weights of the various items. This is demonstrated in the “Piping Material Estimate Template” tab within the file.

The following inputs are required to auto-read the weights from the various tables:

  • Item description (pre-defined)
  • Sizes (in inches)
  • Schedule for pipes and fittings (e.g. 40, 80 etc.)
  • Pressure rating or piping class for flanges and valves (e.g. 150#, 300#, 600# etc.)

The file shows how the inputs should be tabulated and listed to make this work. The formulae can be repeated for thousands of rows of MTOs helping to get the weights within minutes. And using the $/kg rates, the whole piping estimate can be done within a few hours (or even minutes), rather than weeks.

In case of resource shortage, this tool can be used as an effective estimating method; it can also be used by the reviewers to check if the piping estimate done by other more time-consuming methods are in the right ball park. Moreover, a blank inputs table can be shared with the piping engineers to make sure that the inputs come in this prescribed format, thus reducing the time required for any re-formatting.

I have been successfully using this method for many years and would suggest that this is one of the ways the estimating community can increase the team’s productivity and provide better “value for money” by substantially reducing the time and cost for estimating.

Note: These are standard product weights from some manufacturers. Products from specific manufacturers could vary slightly in weight. If the same weight tables are used to calculate the $/kg rate than these slight variations will not make any difference.

Also note that if the design requires non-standard sizes, then the weight of those piping items would need to be calculated from first principles.

Quick Piping Material Estimate

Vikas Khaitan6 Comments

When estimating any oil & gas project, detailed piping estimate is one of the most time-consuming elements. Piping material take-offs can sometimes be in the form of several hundred or even thousands of line items, which an estimator takes weeks to estimate. Some companies have specific piping estimators for the job.

In all oil & gas projects, there are several pipes going in and out of the various equipment items helping the process and utility fluids to move around in the required direction and destination. This piping forms a major portion of the final plant and the cost estimate. There are several piping items such as: pipes, fittings of various kinds, flanges of various kinds, valves of various kinds, and the corresponding gaskets and fasteners. There could be several sizes and pressure ratings of the various piping items. And then there may also be various metallurgies involved. The material take-offs are generally done separately for various lines, which means, similar items could be repeated several times. The whole list is generally very long by the time it comes for estimating.

The piping estimator then tries to find the cost of individual line items from the in-house database and invariably takes a long time to find an exact match for the material, size and schedule of a specific piping item. If the company has previously used similar items in another recent project, then there might be a possibility of getting some in-house data, but even then, it might not be available for all items. The team might end up factoring those items from another nearby size and/or schedule. This whole process is very laborious. Even with databases and software, no company could have an exhaustive databank of prices of all possible piping items.

Depending on the budget and resources available, the team might decide to go out to the market to get recent prices for all the piping items, but even that takes a considerable amount of time.

Once this laborious process is completed, it becomes very difficult to review the overall estimated piping supply cost, as it is nearly impossible to go through each line item.

I am going to suggest a surprisingly simple method to help expedite the piping estimate and review process. For this, all piping items can be converted into weights and then multiplied with an average $/kg rate for the various types of piping items to arrive at a rough piping material supply estimate for comparison.

The table below offers indicative benchmark average $/kg rates for various carbon steel piping items (free estimating resource).

You can choose to use company specific rough $/kg rates for various piping items (instead of the above rates), which can be derived by using database information from past projects or previously obtained budget quotes. This is preparatory work, which can be done when there is less load on the estimating team. Similar rate tables can also be developed for other material such as stainless steel or duplex steel, or factors can be developed to modify the $/kg rates from carbon steel to the higher grades of material. (I will try to post indicative factors as a future blog.)

The weight tabulations for various piping items can be easily obtained from manufacturers of pipes, fittings, flanges and valves (I will share the piping weight tabulation in another post).

This method helps in quickly estimating a rough number for the material cost of all piping items. This can either be used when there is insufficient time or estimating resources to complete a more detailed estimate, or used by the reviewer of the estimate to cross-check the piping estimate done by others. If the weight tables are properly set up then this method can help arrive at a rough piping estimate within hours (or even minutes if the inputs are provided in specified formats), against weeks of work that is generally undertaken.

Note: The benchmark rates above are indicative only and intended to demonstrate how this method would work; they can help arrive at a reliable overall piping material estimate when time is short. 

Piling Costs: Rough Estimate Model for Benchmarking

Vikas Khaitan1 Comment

Once when trying to benchmark piling costs with available information from various in-house projects, the data showed an apparently inexplicable variation in the $/m rate for the piling works. In some cases, it showed 2-3 times the $/m rate for the same diameter, and in other cases, the data showed similar $/m rate even though the diameters varied between projects.

After the initial failed benchmarking exercise, I started considering the technicalities of piling and understood that there are different kinds of piling specified for various projects depending on different soil and project conditions. I realised that I was making the mistake of comparing the $/m rate of different piling types used in different projects. This wrong comparison had created the above-mentioned variations in the overall rate.  At this point, I separated the available data into the various types of pilings. That was a good start, but then I did not have enough data points for the individual piling types to be able to generate any sensible benchmarking curves.

But benchmarking was needed for the estimate approval process.

To meet this need, I developed a small estimate model to calculate the rough $/m cost for various types of piling and for various diameters. I assumed an indicative length of pile to generate the graph. I used indicative material and labour rates, norms and productivity factors to calculate the cost of the various types of piling. I included an indicative hiring cost of piling hammer or rig as required for a specific type of piling work. All these inputs and assumptions could be modified for specific project and location to help generate a customised benchmarking graph. I have also assumed a total number of pile for this specific example and would caution that the per meter rate could substantially vary if the total quantity is significantly different. But this still gives an idea and relative cost differences

The attached file shows the proposed working.

Piling Rough Estimate Model for Benchmarking-Rev0 (free resource)

This shows how the costs could possibly vary with diameter and piling type and can be used as an in-house estimated benchmarking graph. Any past project data (if available) could be superimposed on this graph for easy comparison. Any contractor bids can then be compared against this graph to demonstrate the reasonableness of market pricing. This can also help the engineers choose and compare more than one piling type, if technically suitable, to use in a project.

Estimating Time Management

Vikas KhaitanLeave a comment

Estimating time management has always been an issue in the all estimating departments which affects the quality of estimates being produced. I would like to discuss how an estimator generally plans his estimating work for a project and how we should be approaching it so as to avoid the last minute rush that is generally experienced in all estimating departments.

The following figure shows a typical estimating schedule

The important points to note in the above figure are:

  • There is a long waiting time by the estimating group between the start of the process and when they actually start getting inputs from the various disciplines.
  • Once the inputs come in there is very little time left before the estimate needs to be complete.
  • The management generally reviews the estimate before the last input has come in.
  • The final estimate needs to be submitted very soon after the last input has come in.

Most estimators deal with this typical situation in the following way:

  • The estimator does not start work before the first input starts coming in.
  • The accuracy of the estimate is compromised and reduced; the estimator blames this on the late receipt of inputs.
  • The late inputs, which arrive after the management reviews, are typically not incorporated into the estimate as there is “not enough time” to do so, or added as very high-level order of magnitude estimates in the form of late changes.

I will propose an alternative to this unsatisfactory approach, based on methods which I have been successfully using for the last several years while working as an estimator.

During the kick-off meeting at the start of the project / proposal effort, the estimator will get a fair idea of what the designers are going to design and typically how similar or dissimilar the new design will roughly be to something done by the company in the past. During the long waiting time, before even a single input has come from the disciplines, the estimator can actually complete a detailed estimate based on the available past project information and come up with the as-of-date estimate of the past project. As a lot of time is required by the estimator to gather typical prices from various sources to use in the estimate preparation, that work will have been done during this process. Another important thing, which takes a lot of the estimator’s time, is the formatting, presentation and management approval of the estimate. If based on an old but similar project / proposal information, the managers are usually quite happy to discuss the results of the as-of-date estimate of that old project, comment and advice on it, and review it. This helps in finalising the estimate even before any input has been provided. This brings forward the time generally spent on the activities at the end of the estimating process. Thus, when the inputs do come in, it takes very little time to update the estimate with the revised (or correct) quantities. The approval cycle is also faster as everybody is already familiar with the cost basis.

I have taken this approach even for projects where there was no historical data available, but people were able to give me a fair idea of what the final product would be like, so that I could assume dummy quantities for my format preparation and basic cost information search.

The following are the advantages of such an approach:

  • No last-minute-rush situation, as the work is evenly distributed during the actual time available for an estimate.
  • More time spent on cost database searches and approaching vendors (if required), thus making the cost basis more accurate.
  • More review time available by the managers.
  • More suitable for training new estimators as there is no pressure on the team to complete an estimate thus requiring some experienced estimator to quickly start and finish the estimate when the inputs come in.
  • Frees the experienced estimator’s time to perform a more supervisory role.
  • Gives better understanding of what kind of inputs are required to complete the estimate and could be used to guide the new discipline engineers on the job to formulate their outputs accordingly.
  • Last but not the least, it gives a clearer idea to the managers about the range of the final figure; this helps them to design their selling pitch accordingly.

I would like to argue that managing and utilising the total available time for any estimate is a more sensible approach, which produces accurate and more reliable estimates.

This article formed part of a larger opinion piece published in Nov-2015, in the Project Control Professional which is the journal of The Association of Cost Engineers.

Design Option Selection Estimate Layout

Vikas KhaitanLeave a comment

During the initial phases of any project, there are multiple technical solutions that the team could choose from for the overall design or for individual technical details. These various options need cost comparisons for effective selection and decision making. It sometimes is a challenge for the team, to get everybody involved to agree on a single solution. But a proper layout and presentation of these estimates could help to ease the understanding and in the decision making.

When presenting an option selection cost estimate, it is very important to tabulate the varying scopes (at a high level), alongside the costs to transparently present the differences in scopes between the various options. I would also recommend presenting all the options in a single tabulation if possible. This helps in easy comparison of the scope differences and then to see how the overall cost varies.  A single tabulation would help during any discussions with the technical team and might highlight any items that could have been missed or not defined correctly when compared to each other.

Also, the unit cost basis for any individual item should not vary between the options. Any variation in unit cost should imply a new item description. The only difference between the options should be the quantity of individual items. Keeping the same unit cost basis gives the confidence to the decision makers that they really are choosing between different technical options. Do note that there could be specific items in an option that may not be required for other options.

Attached is a dummy template that could be used for any option selection estimate. I have personally used similar tabulation for various study estimates and successfully helped in the decision-making process.

Design Option Selection Estimate template (free estimating resource)

Case in point:

In a particular project, involving a wide range of technical solutions, various options were estimated and the cost summaries of the individual options presented separately. This did not easily allow the decision makers to understand the technical differences between the options. When reviewing the cost estimate, most of the time was spent in understanding the technical differences and the reasoning behind them, as it was not easily obvious why the costs of the various options were so different, and what benefit did the project get by investing more money. The technical scope and costs being separated, did not lend itself to easy decision making and no decision was taken. It took the team months to select an option.

I have been practicing presenting design option estimates in a single page layout and have most of the times successfully convinced the team to easily understand the various options technically and commercially. This has always been helpful in decision making and sometimes only within a single meeting.

Note:

Not all items that are included in an option selection estimates can necessarily become part of a single project. For instance, when deciding between two plot spaces for a process plant, the road that needs to be built could be of different length in each option and might help decide which is a more favourable overall cost project, but the actual road might not be included in the project scope at all.

This example shows that all scope differences, even beyond the current project boundaries, should be considered when trying to select between various competing designs and projects.

Thumb Rules for Engineering Costs

Vikas Khaitan5 Comments
2–3 minutes

Sometimes a very rough high level engineering cost for a future project might be needed for budget approvals, initial planning, contracting strategy discussions, benchmarking of bid prices or negotiating with the engineering contractors. The rough cost could also be helpful to plan the manning level in the design office.

As a thumb rule, for most Oil & Gas projects, typically, the engineering costs generally ranges between 5 and 15% of the overall CAPEX (Capital Expenditure), depending on the scope of engineering required, project size, complexity, brownfield / greenfield development etc.

The percentage will be at the lower end for a larger project (higher CAPEX) and will tend to be at the higher end for smaller CAPEX projects.

The various engineering scopes that could be included in any one or more engineering contractor’s scope of work could be as follows:

  • Concept work
  • Pre-FEED engineering
  • FEED engineering
  • Detailed engineering
  • Procurement services
  • Follow-on engineering
  • Site survey works

The below tabulation shows typical indicative engineering costs for various projects with varying CAPEX values

20170218-enginnering-cost-thumb-rules-rev0

Engineering Cost Thumb Rules (Excel Version) – free estimating resourceDownload

These rough percentages are very much high level indicative numbers, based on experience, to just help with a quick calculation of the total engineering costs. The table above can be utilised to calculate the indicative high level cost for the engineering effort required for a scope (for example, only FEED engineering, or only detailed engineering etc.).

The actual engineering cost for individual projects will depend on the project complexity, location of engineering, available skill level, previous experience with the technology and many other factors.

Ideally, of course, deliverables and activity based resource requirement would be established and costed by Individual estimators / project engineers to arrive at the overall engineering cost for the required scope. The high-level percentages suggested in this post can still be useful in such a case; they can be used as a rough guide to review, cross-check and critic the detailed calculation.

Note: The actual percentage for all the above scope of work could sometimes be much more than 15% of the overall CAPEX for small projects. The percentage could end up being less than 5% for very large CAPEX projects, specifically those which have several repeatable portions which make the total value of the project high, but would not require multiple engineering effort.

View Paid Services
New! Check out what is Flextimate™

Who Owns the Scope?

Vikas Khaitan4 Comments

I have always believed that for a project someone, either on the client side or on the contractor side, must know the complete scope. As an estimator, I always try to acquire a complete understanding of the project by identifying a Scope of Work document or, if that is not available, then speak to several different people to get a better understanding of the scope. I am constantly surprised by how vague most documents are about scope, and how nobody ever seems to know the complete scope.

The following could be a typical situation in many cases:

Client’s Team: Everybody in the client’s team thinks that the contractors are the professionals, so they must know the scope.

Contractor’s Team: Contractor team members think that the client knows what they are paying for and so the client team members should know the scope.

Project Managers: Most Project Managers, instead of being managers of projects are mostly managers of people. They think that if they can get the right team, the project can be executed.

Project Engineers: They act like mini-project managers, and they too end up managing others without trying to grasp the technical scope.

Procurement Team: Procurement personnel are mostly concerned with placing a contract or purchase order and believe the scope to be the purview of the technical team. They go through the whole procurement process without ever understanding the real scope as such.

Coming to the technical team, it is even more surprising. Every discipline somehow does their bit but are never sure what the overall scope is or what the boundary limits are. Process engineers do the basic design, equipment list, process flow diagrams, but, for example, they may not be sure whether supply of all chemicals are in the scope of work. They may also not be clear what additional non-process equipment might be needed to complete the project. Electrical, instruments, civil, mechanical discipline engineers similarly provide their part of the basic design and item list, again most being oblivious of the complete project scope, some even missing less obvious items related to their own disciplines.

Many interfaces between the various disciplines are sometimes missed. A good example would be the cable trenching – the electrical discipline would not include it and say it is the civil group’s scope and the civil group might sometimes miss it saying the electrical discipline should consider it. Similarly, actuators on piping valves go missing as it could be either a piping item or an instrument item and sometimes both disciplines either omit it from their scope or both include it and there could be a chance of double dipping of scope and hence cost.

Finally, when the overall design comes to the estimator from the various disciplines, the information when added together generally does not complete the picture. Most estimators complain that the scope to be estimated is not clearly defined, and therefore they very promptly proclaim that the accuracy required of the estimate cannot be achieved.

The basic idea behind this complaint is that the estimators will, in isolation, produce an estimate for a defined scope and would have no role to play in defining the scope. I think, in some situations, where coincidentlly no other person is joining the dots, the estimator can step up and help in this aspect. Estimators are responsible for bringing it all together anyway and come up with a number to bid or set a budget. Therefore, they do somehow have to know the complete scope, even if some of it is based on similar projects executed in the past. Estimators can make data related to cost, scope and other technical aspects of similar past projects available to the entire team, and thus assist in completing the overall scope definition. This in turn will help the project and the technical teams to provide the right inputs to estimating thus helping achieve the required estimate accuracy and helping the whole team understand the project / proposal scope better.

Estimating as a function can start taking responsibility for the complete scope of projects and fill this very common gap in some situations.

Supplier Quotes for Estimating

Vikas Khaitan3 Comments

One of the important steps during any estimate preparation is obtaining supplier quotations. Some pricing is based on in-house data from past projects or previously obtained budget quotes, but there is generally a requirement to get latest market pricing for high value items to increase the accuracy of any estimate. The time to obtain these quotations is mostly built into the estimate preparation time. On many occasions, this time may appear inadequate and the team could be unsuccessful in obtaining any meaningful and usable quotations to be included in the estimates thus affecting the estimate accuracy.

In this blog, I will first discuss what tends to be the general approach for obtaining quotations at the estimating stage of any project, and then I will propose a method for making this process more efficient to fit with the available estimate preparation time.

One of the issues I have noticed as part of many teams is the format in which the request is sent out to the suppliers. The requirement, scope descriptions, specifications etc. are sent to the supplier without any pricing format / tabulation to be filled. Every supplier thus interprets the client’s requirement in a different way and submits a priced quotation in varying formats. It then takes a long time to understand the overall pricing being quoted by the suppliers, obtain clarifications if required and then normalise the scope to compare them on an equal footing. It is always a challenge to tabulate, compare, analyse and then suitably use the quotes, in the estimate.

I propose that the estimator should support the engineering/ procurement team in developing suitable tabulations of the required scope to be sent to the suppliers. If all the suppliers are given the same price schedule in an Excel format for example, when the prices come in, it would be an easy task for the team to tabulate the submissions from the various bids and compare them against one another. Any duplication of effort would be immediately removed from the system. No time would be wasted in trying to copy each line item and its quoted price into a spreadsheet. Any comparison and further analysis would become much easier. Any adjustment to the scope and quantities would be easy to make as well. It would reduce the time for any clarifications and bid evaluations, thus allowing the estimate preparation to be completed within time and with a high accuracy.

Case in point

Long ago, when I joined an estimating team of a company, I found that the very detailed quotes which we received from various contractors for fabrication of our equipment, varied widely in terms of the format in which they were quoted. This was partly down to us; we as a team were not very clear in our scope description, hence the quotes were also not very clear on what was included. Small things like painting was sometimes missed out from the bids, or it was not clear if the lifting lugs for transportation and site installation were included or not, or if anchor bolts were missed out. The small items when combined did make a difference to the bottom line and the estimates could end up either double dipping on those items or missing them out completely. We had to have several clarifications before we could compare the various bids and it sometimes took weeks or even months. I realised there was a problem and it affected our ability to produce effective estimates in a timely manner. I helped the team develop a simple excel format to go out to the contractors for pricing for any new enquiries and the template included all the information we needed all suitably tabulated. This then made it easy for the various bidders to quote their prices, quick and easy for us to check if everybody quoted all the items, and even easier to compare different bids and then suitably include the costs into the overall estimates. We reduced the overall time from weeks / months to nearly less than a day for the whole exercise once the contractors’ quotes came in.

I have now made it a practice to help any new team I work with, to develop suitable formats to obtain quotes so that it makes it efficient for everybody involved. If you do not do this already, I would highly recommend it.

Attached is a dummy format in excel for reference.

20161026-dummy-price-schedule (free resource)

Owner Vs Contractor Estimates

Vikas KhaitanLeave a comment

Depending on who is looking at an estimate and for what purpose, the actual estimate could be different for the apparently same scope or project. For example, owner estimates could be different from a contractor’s estimate.

Generally, when an estimate is prepared by a contractor, it is for a defined scope of work. But when an owner company wants to estimate for its own internal budget approvals, it is for a “Project”. This means that even if an initial scope is defined, there is always a high chance of scope creep during the course of the project sanctioning process. It is not easy to define all the requirements during the initial stages and with time generally more scope is added to the project for completeness. The estimator in the client’s estimating team should thus be able to correctly pitch the overall number to the funding body in order to encompass possible future scope additions. This adds certain challenges to the process of preparing the estimate.

Contractor estimates are generally for bidding purposes or to generate indicative numbers alongside front-end engineering design work; these are related to a particular scope definition. Any change in scope goes through a change management process and could require additional funding. The point is that somebody has to pay that additional amount, and if the client’s original budget did not envisage those changes, then there will be no budget to pay from. This is different from the contingency amount generally added to the estimates for design refinement and other estimate deficiencies for that particular scope.

The contractor’s estimator always tries to prepare the estimate taking into account the entire scope as defined in the “Scope of Work” document. But when an estimator in the client’s team looks at the same document, they need to double check with their own team whether that particular scope will really deliver the project or if additional facilities / scope will be needed to actually complete the work. The answer can be found by understanding the overall process requirement and also from evaluating previous projects of a similar nature. It is worth keeping in mind here that the ultimate body which approves the overall budget, does not approve a scope of work but a project which promises to deliver a product spec of some fashion. It could be a plant which processes a certain capacity of treated water at a particular purity, or certain oil production rate at a particular specification, or generates certain capacity of power, or a pipeline which is able to transfer certain quantity of fluids.

Several additional items might not be in the initial scope or part of a contractor’s estimate but are needed for the overall approval and actual completion of the project. Examples of such items, which should be considered by the estimator in the client’s team are as follows:

  • Owner’s management costs
  • Land costs
  • Social and environmental impact costs (which could be a significant amount for some projects and could also impact the viability of the project)
  • Cost of treating the by-products (which might not be part of the initial scope definition, but is essential to estimate the project cost completely, without which the project would become unviable)
  • Cost of additional utilities like gas or power without which the current project will not deliver
  • Cost of tying into existing facilities or additional peripheral facilities to export the product
  • Cost of additional infrastructure required in the region or the country without which the project could not be completed

It might not be always possible to estimate these items at the initial stages during the funding approval process as proper definition might not be available, thus making the job of the estimator in the owner’s team quite difficult. But a very rough high level assessment of these costs could be useful. Nothing should be actually excluded when getting the overall project sanctioned.

Professionals in this field are aware that generally large projects are approved against competing projects which address the current industry, business, political, environmental and social needs in different ways. Thus giving a complete picture helps the approving bodies with the selection and the decision making as the chances of any future surprises are greatly reduced.

This article was published as an opinion piece in July-2017, in the Project Control Professional which is the journal of The Association of Cost Engineers.

Estimate Ownership

Vikas KhaitanLeave a comment

In one of my earlier posts, I presented a template for an estimate summary which highlighted some minimum requirements to make it look professional. One of the items was the estimator’s initials and the date of the estimate in the estimate summary. This is not a minor formatting issue; I think it is something crucial about taking responsibility and in turn providing reliability.

Without any date and a name / signature or even an initial, an estimate would be incomplete and it would only be a set of numbers with limited credibility and difficult to use. Anybody else looking at the estimate would find it difficult to trace the logic behind it and/or the validation process. The estimator himself could find it difficult to remember his or her own logic at a future date.  Even a brilliant estimate might end up being ignored for this seemingly small reason.

Anybody preparing an estimate should be able to take responsibility for their work. His or her name / initials or signature shows that responsibility. There are bound to be questions / challenges on any estimate. A good estimator should always be prepared and willing to respond to such queries. And even after the immediate context is long forgotten, somebody might pick it up, and then they would want to know more about it. The estimator’s name at least gives it an ownership and a possibility to query the numbers, adding traceability. The date also helps put a time and context to the historical work done and could be useful for any future updates when the cost basis, technology and/or client requirements change.

I have seen many estimates without any date or initials. I have personally struggled to understand them or even enquire who did it in the first place, let alone establish the old estimate basis.

I think, if nothing else, it is good practice. The quality of work and presentation changes considerably if it is to be initialled by the estimator herself. Some businesses require final estimates to be approved and signed by more than one person. This requirement just brings in that extra rigour in what you prepare and present. Even if there is no formal procedure / requirement for any signatures, I would recommend that at least the person who is preparing the estimate signs it. It will show to the rest of the team that there is at least one person who is willing to own the numbers and if needed explain them. In my view it will definitely contribute to most company’s teamwork and work-ownership ethos.

I have made it a personal practice / habit to put my initial down on any estimate I do, even if it is a back of an envelope type very quick calculation. To start with it reminds me later what I did, why I did it and what the reason behind it was. I am then able to better explain what I did if anybody questions the basis of the estimate.

By definition estimates are wrong and it does take a lot of confidence to stand behind them.