OIR 26.1 Release Notes

Released September 22, 2026 to all CSI Dynamic Standards customers

CSI Standards continue to be governed, developed, and approved through The Construction Specifications Institute’s (CSI’s) established consensus process. The current Editions of MasterFormat^®, UniFormat^®, and OmniClass^® remain the authoritative standards and change only through CSI's formal governance process. The Construction Standard delivers those approved Standards through the CSI Dynamic Standards℠ (CDS) environment, where Operational Information Releases (OIRs) provide ongoing improvements to the digital information ecosystem without changing the underlying standard editions.

For this Operational Information Release, the Construction Information Network (CIN), through The Construction Standard, has addressed a substantial backlog of editorial and publication inconsistencies that had accumulated over many years within previously published Standards. More than 900 formatting, terminology, metadata, and classification corrections have been incorporated into the digital environment. These improvements correct publication inconsistencies and enhance the quality, usability, and interoperability of the information presented through CDS. They do not represent revisions to the approved CSI standard editions.

As CSI completes future standards work through its volunteer committees and established governance process, those approved changes will be incorporated into subsequent OIRs. This approach allows the digital environment to remain current and responsive while preserving the stability, authority, and continuity of CSI standard editions. For software developers and enterprise users, OIRs provide predictable versioning for APIs and digital integrations. For most CSI members, the experience will simply be a continually improving digital environment built upon the same trusted Standards.

This OIR also introduces a new navigation guide within the CDS user experience to help users better understand the relationships between Divisions, Entities, and Tables across MasterFormat, UniFormat, and OmniClass. The guide is intended to improve navigation and understanding of the CSI family of Standards and does not modify the Standards themselves.

UniFormat Expansion Reflected in CDS Operational Information Release 26.1

As part of CSI's ongoing standards development program, the CSI UniFormat Maintenance Task Team, under the oversight of the CSI Standards Steering Committee, is developing a significant expansion of UniFormat beyond its traditional focus on Elements associated with the Building Entity.

This work represents the next stage in the evolution of UniFormat and is being developed through CSI's established standards development and consensus process. The proposed framework is intended to extend UniFormat into additional infrastructure entities while maintaining consistency with the principles that have guided the Standard since its inception.

The current OIR 26.1 within the CDS environment reflects the initial framework developed by the Task Team. It is important to recognize that this work remains under active development and should be viewed as the beginning of an expanding classification structure rather than a completed Standard.

The initial framework includes proposed characterizations for:

Transportation Characterizations

• Table 02 – Roadway Entities
• Table 03 – Bridge Entities
• Table 04 – Railway Entities
• Table 05 – Airfield Entities

Utility and Service Characterizations

• Table 14 – Water, Wastewater, and Stormwater Entities
• Table 17 – Electric Power System Entities
• Table 18 – Oil and Gas Entities
• Table 19 – Communication Entities

These proposed characterization and entity structures establish the organizational framework from which additional expansions will be developed. They represent the current progress of the UniFormat Maintenance Task Team and will continue to evolve as recommendations are reviewed, refined, and advanced through CSI's standards development process.

The decision to develop these characterizations concurrently reflects the technical relationships identified by the UniFormat Maintenance Task Team. Many of the entities share common element descriptions, terminology, and coordination requirements, allowing proposals to be developed collaboratively while maintaining consistency across the expanding UniFormat framework.

As additional work is completed and progressed through the CSI standards process, future OIRs will be updated to reflect that progress. OIRs therefore provide visibility into the current state of the digital information environment while the underlying Standard continues to evolve through CSI's established governance process, and the existing UniFormat 2010 Edition remains as a stable reference for CSI Member Subscribers.

Crosswalks Across Standards

Until now, UniFormat’s references to MasterFormat had not kept pace with MasterFormat’s growth over the years (~16,000 structural changes since 2010 between new numbers, refinements, and expansion from parent to descendent). UniFormat has referenced MasterFormat 2010 since its own last update. That reference was kept in place on purpose to maintain the historical documentation, but this made it harder to reliably connect designs to specifications and what is actually being built through each new edition of MasterFormat.

OIR 26.1 addresses this by representing each classification as a single information record within the operational information model. Each record maintains the relationship between a UniFormat Element and its associated MasterFormat Work Results and OmniClass Table. For example:

For illustrative purposes*

The operational information model has been designed to support future standards initiatives as they are developed and approved by CSI. One proposal currently being explored by the Standards Steering Committee considers expanding the role of the Preliminary Project Description into a broader Project Planning Document (PPD). While still in the early planning stages, the CDS relationship model demonstrates how future planning information could be connected to classifications, specifications, procurement, construction, and operations without requiring changes to the underlying information architecture.

Data Quality and Consistency

This release includes a cleanup of the manually entered data built up across MasterFormat, UniFormat, and OmniClass over many years. This release corrects transcription errors and standardizes formatting that were never reconciled: numbering and identifier formats, singular and plural terminology, spacing and punctuation, hard spaces and non-breaking hyphens, and naming conventions that affect how entities relate to one another.

Most of this work has no visible interface. Its effect appears in search results that resolve correctly, and crosswalk matches that succeed where they previously failed.

What’s Not in This Release

The Transportation and Utility/Service entities added in the OIR 26.1 are a starting point. Sections of each table are reserved for future expansion as CSI’s UniFormat Maintenance Task Team continues developing the classifications, delivered through CDS in coordinated releases going forward, across all three standards, each smaller than a full edition. CSI’s planned future entities include Underground, Water Retention and Control, Waterfront, Waterway and Marine, Manufacturing, Natural, and Recreation, subject to CSI’s editorial priorities and review.

What You’ll Notice Over Time, and Where OIR 26.1 Adds Up

Much of the value of OIR 26.1 comes from correcting thousands of small inconsistencies in the underlying data. There is a visible addition: a new navigator guide, described below. The rest works like correcting entries across a dictionary where no single fix stands out, but every lookup becomes more reliable.

Cross-Standard Navigation

Before: A UniFormat entity pointed to one representative MasterFormat classification. Finding the rest of what was needed often required significant standards experience and manual research.

With OIR 26.1: A user can move from a UniFormat element directly to its related MasterFormat and OmniClass entities through built-in crosswalks.

Search Reliability

Before: Search depended on exact terminology, since inconsistencies had accumulated over years of manual entry.

With OIR 26.1: Corrected terminology, formatting, and numbering make relevant results easier to find, even without the exact published term.

Legacy to Current Standards

Before: Understanding how a classification changed from one release to another meant manual research – there was no single view showing a classification’s history across MasterFormat, UniFormat, and OmniClass releases.

With OIR 26.1: A new transition tool lets users see how classifications have changed from one release to another in a single view. For UniFormat and OmniClass, users can compare the 2010 release to OIR 26.1 and view the predecessors for each current classification, including whether a classification had a number change, a title change, or both. For MasterFormat, the same concept applies across releases – for example, comparing MasterFormat 2026 / OIR 26.1 against MasterFormat 2020 shows the classification-by-classification transitions, including number and title changes. There were no transitions between the initial 2026 release and OIR 26.1, so the tool becomes most useful comparing OIR 26.1 back to 2020. Going forward, this is intended to be a permanent way for customers to compare the release they are currently using against the latest OIR, making it easier for companies to understand what changed and update internal libraries, databases, specifications, or other systems accordingly.

Standards Navigator Guide

Before: Finding a starting point in the standards meant already knowing roughly where to look – which division, entity, or table applied to a given item.

With OIR 26.1: A new division view in the CDS navigator lets users browse the standards hierarchically, rather than relying only on search. Users can move through the structure of MasterFormat, UniFormat, and OmniClass and see where an individual classification sits within the broader hierarchy, without needing to already know its title or number. For users accustomed to navigating the standards in printed or PDF form, this offers a browsing experience closer to paging through a familiar table of contents, easing the transition into a digital environment rather than requiring search fluency from day one.

Read the 26.1 announcement from Chris Anderson, CEO of The Construction Standard.