CSI MasterFormat Basics

Organize your construction specs and project information

Engineers and construction workers reviewing blueprints at construction site
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MasterFormat is a coding system for organizing construction documents, contracts, design specifications, and operational manuals. It uses specific numbers and associated titles that make up a universal indexing system. MasterFormat is also a publication created and maintained by the Construction Specification Institute (CSI) and Construction Specifications Canada (CSC). It is widely used in the construction and operation of buildings and systems in a variety of industries and projects, from hospitals and public infrastructure to schools and residential construction.

Advantages of Using MasterFormat

One of the most important benefits of MasterFormat is improved communication between project groups, most notably between the design and construction teams. It allows all team members to refer to specific sections of any document using the universal coding system. This facilitates coordination and communication between project owners, architects, contractors, and suppliers, minimizing the time spent organizing documents.

For industries with complex operations, such as health care, MasterFormat helps communicate and organize critical operational information among designers, builders, operations managers, and facility owners. In addition, as these and many other industries are increasingly using building information modeling, or BIM, MasterFormat can be used by modeling software to enhance data interoperability and improve BIM adoption.

The MasterFormat system can be used to organize many types of project documents, including:

  • Design specifications
  • Project manuals
  • Drawings (keynotes)
  • Product literature/data filing
  • Facility management and maintenance
  • Project integration and communication
  • Detailed cost estimating/project accounting
  • Building information modeling

MasterFormat Divisions and Subgroups

MasterFormat includes a group of "50 divisions" of construction information. Each division has its own number. Prior to 2004, there were just 16 divisions, and the system has been expanding and evolving ever since. The divisions and subgroups are as follows:


00 Procurement and Contracting Requirements


General Requirements Subgroup

01 General Requirements

Facility Construction Subgroup

02 Existing Conditions

03 Concrete

04 Masonry

05 Metals

06 Wood, Plastics, and Composites

07 Thermal and Moisture Protection

08 Openings

09 Finishes

10 Specialties

11 Equipment

12 Furnishings

13 Special Construction

14 Conveying Equipment

15–19 Reserved for Future Expansion

Facility Services Subgroup

20 Mechanical Support

21 Fire Suppression

22 Plumbing

23 Heating, Ventilating, and Air Conditioning (HVAC)

24 Reserved

25 Integrated Automation

26 Electrical

27 Communications

28 Electronic Safety and Security

29 Reserved for Future Expansion

Site and Infrastructure Subgroup

30 Reserved for Future Expansion

31 Earthwork

32 Exterior Improvements

33 Utilities

34 Transportation

35 Waterway and Marine Construction

36–39 Reserved for Future Expansion

Process Equipment Subgroup

40 Process Integration

41 Material Processing and Handling Equipment

42 Process Heating, Cooling, and Drying Equipment

43 Process Gas and Liquid Handling, Purification, and Storage Equipment

44 Pollution and Waste Control Equipment

45 Industry-Specific Manufacturing Equipment

46 Water and Wastewater Equipment 

47 Reserved for Future Expansion

48 Electrical Power Generation

49 Reserved for Future Expansion

MasterFormat Updates

MasterFormat is updated annually, and suggestions for revisions can be submitted to CSI at any time. For the latest updates, visit the MasterFormat revisions page. One example of a significant past revision is the change from a five-digit format to a six-digit numbering system for the sections within the divisions. The newer system creates room for adding many additional sections as needed. Revisions and updates like these allow MasterFormat to evolve as needed, based on user demand.