Material Cost

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.