History of CSI MasterFormat

CSI Masterformat

CSI MasterFormat

CSI MasterFormat


For anyone new to construction, it seems like we speak a different language. We’re always referring to a division, section, or title to communicate during the design and construction.  Sooner or later your start to hearing about something called CSI MasterFormat. 


But when did all of this start? Who standardized the way we refer to documents? With a little reading, here’s what I learned.


In the first half of the 20th century, construction projects had no consistency from project to project. A California project might specify concrete in Section 8A, while in Texas, Section 32 defines the same scope. Locating information was troublesome and time-consuming for the entire industry.


To solve the challenge of consistency, a group of engineers who worked for various US government agencies in 1947 began meeting informally to discuss how to create a more uniform specification system. A better way of creating consistency and specifying work results and construction requirements was their focus.


Construction Specifications Institute (CSI)


The engineer’s informal meetings grew into what we know today as the Construction Specifications Institute (CSI) in 1948. An industry-wide organization with a primary goal of advancing specifications and developing a systematic approach to organizing construction documents and standardizing forms.


In 1963, CSI MasterFormat was released, a numbering system with titles for organizing construction information into 16 Divisions and a five-digit numbering system called Sections, and a standard way of organizing the information and the communication we all use today.


Today, many of us refer to MasterFormat as the “Dewey Decimal System” of organizing specifications. It promotes standardization, facilitates retrieval of information, and improved communication among all parties involved in construction projects.


So the next time you work on a project and start referring to the divisions, section numbers, and titles, remember it was a group of engineers that set in motion the standard communication we use today.


CSI MasterFormat Divisions (Current) 


In 2004, CSI MasterFormat was updated to 50 Divisions and expanded the numbering sequence (Sections) to a six-digit numbering sequence to continue CSI MasterFormat’s growth. The expansion’s primary reason was to address overcrowded divisions and additional divisions to include infrastructure and process equipment. The numbering sequence (Sections) and titles are updated roughly every two years. Check out a recent edition of CSI MasterFormat at this link.


To see CSI MasterFormat in action, check out the latest SimpleSpecs™ by packages:

Architectural specifications 

Historic Preservation 

Site Civil specifications

Structural specifications 

Interiors specifications 

Landscape specifications

Comprehensive specifications 


  • Division 00 — Procurement and Contracting Requirements


General Requirements Subgroup
  • Division 01 — General Requirements
Facility Construction Subgroup
  • Division 02 — Existing Conditions
  • Division 03 — Concrete
  • Division 04 — Masonry
  • Division 05 — Metals
  • Division 06 — Wood, Plastics, and Composites
  • Division 07 — Thermal and Moisture Protection
  • Division 08 — Openings
  • Division 09 — Finishes
  • Division 10 — Specialties
  • Division 11 — Equipment
  • Division 12 — Furnishings
  • Division 13 — Special Construction
  • Division 14 — Conveying Equipment
Facility Services Subgroup:
  • Division 21 — Fire Suppression
  • Division 22 — Plumbing
  • Division 23 — Heating, Ventilating, and Air Conditioning (HVAC)
  • Division 25 — Integrated Automation
  • Division 26 — Electrical
  • Division 27 — Communications
  • Division 28 — Electronic Safety and Security
Site and Infrastructure Subgroup:
  • Division 31 — Earthwork
  • Division 32 — Exterior Improvements
  • Division 33 — Utilities
  • Division 34 — Transportation
  • Division 35 — Waterway and Marine Construction
Process Equipment Subgroup:
  • Division 40 — Process Interconnections
  • Division 41 — Material Processing and Handling Equipment
  • Division 42 — Process Heating, Cooling, and Drying Equipment
  • Division 43 — Process Gas and Liquid Handling, Purification and Storage Equipment
  • Division 44 — Pollution and Waste Control Equipment
  • Division 45 — Industry-Specific Manufacturing Equipment
  • Division 46 — Water and Wastewater Equipment
  • Division 48 — Electrical Power Generation