Operate & maintain savings: what the Savings page measures

All amounts are ranges with a middle estimate. They follow the hourly rate and the currency chosen on the Valuation page, and the useful life chosen on the Valuation or Savings page.

1. Which elements an owner maintains

Every element gets an operate & maintain role from its IFC class: equipment (pumps, fans, valves, light fixtures), components (doors, windows, bearings), structure and fabric (walls, slabs, decks, pavement courses), and networks (pipes, ducts, cables and their fittings). Unidentified objects such as building element proxies count as items that first have to be identified. Elements nobody maintains on their own, such as reinforcement, openings, furniture and spaces, are left out.

For infrastructure, structure and fabric are sized from the measured geometry (square metres, metres, cubic metres) rather than counted as objects (see how we measure size), because a bridge deck is inspected by area, not by the number of IFC objects that model it.

2. Which data each element needs

Each role needs a few kinds of data to be maintained without searching or surveying: location, type, classification, product data (manufacturer, model), material, quantity, the system it belongs to, and service life & warranty. The audit measures, per IFC class, how many elements have each kind of data.

3. A maintenance schedule, year by year

ForensicBIM then plans the typical operate & maintain work for this asset over its useful life, year by year: planned maintenance and inspections, repairs, fault finding, condition surveys, alterations, and replacements at the end of each part’s service life. Each task takes less time when the data is in the model and more when it is missing. The yearly saving is the time the data saves at these tasks, at the hourly rate.

• Inspections: at the routine cycle that is usual for the asset type, for example the US federal inspection standards for bridges (NBIS) and tunnels (NTIS).
• Condition surveys: every few years, when quantities and materials have to be measured again if they are not in the model.
• Replacements: around the end of each part’s service life, based on published reference service lives in the spirit of ISO 15686. Replacements are spread over a few years around that point, because identical parts do not all fail in the same year.

4. Operate & maintain property sets in the file

When the file holds these standard IFC property sets, their values replace the defaults:

A property set on a type applies to every element of that type, unless the element has its own value. Empty values and placeholders such as “n/a” count as missing.

5. From hours to money

Time is converted to money at the hourly rate shown on the Valuation page (Pro users can change it), allowing for costs that rise over the years. Value in use brings each future year back to today’s money. Totals over N years and the bars are not discounted, which is why they are higher than value in use.

The Per year view shows the schedule behind the totals. Bars are higher in years with an inspection or a condition survey, and in the years when groups of parts reach the end of their service life and a survey and specification are needed before replacement. Every bar also grows a little each year as costs rise. Bridges and tunnels typically show a two-year rhythm; buildings with short-lived finishes or equipment show a rise towards the end of a 20-year period.

O&M data readiness is the share of the data an owner needs for operation that is already in the file, weighted by how much effort each missing item would take to collect after handover. It is shown overall and in four parts:

• Asset register: location, type, classification, product data and identification.
• Maintenance & renewal plan: materials and quantities.
• Systems & networks: which system each part of an installation belongs to.
• Service life & warranty: the operate & maintain property sets above, for equipment and components.

Files audited before ForensicBIM read the operate & maintain property sets (October 2026) show service life & warranty as not measured. Audit the file again to include it.

• The figures are estimates from the data in the file and typical maintenance practice, not a quote or a maintenance budget.
• The range reflects the spread in typical practice; the middle estimate is the best single figure.
• A model whose data saves nothing gets a value in use of zero. That is a measured result, not an error.
• Owners with their own maintenance records can set their own hourly rate on the Valuation page (a Pro feature); the hours behind the estimate stay the same.
• To raise the value, close the biggest gaps listed on the Potential page, preferably in the model before handover.

• The data value ladder — where value in use sits among the eleven numbers on the Valuation page.
• Which number answers which question? — when to use value in use, and when another number.
• What’s in the hourly rate? — the blended rate that turns hours into money.
• Valuation methodology — how the numbers are built and calibrated.
• How we measure size, and which units you see — the sizes that infrastructure savings follow.
• How to read your report — where the Savings page sits among the other pages.