Who publishes it
The Construction Specifications Institute, or CSI, publishes MasterFormat with Construction Specifications Canada. Architects use it to organize the Project Manual. Estimators use it to find their work. Many cost codes and bid invitations use the same numbers.
How the divisions are laid out
The current edition numbers its divisions from 00 to 49. Some numbers are reserved and not used. An older edition had 16 divisions. Some people still say Division 16 when they mean electrical. In the current edition electrical is Division 26.
- Division 00: procurement and contracting requirements. This is the front end.
- Division 01: general requirements for the whole job.
- Divisions 02 to 14: the building itself. Concrete is 03, openings is 08, finishes is 09, equipment is 11.
- Divisions 21 to 28: building services. Fire suppression is 21, plumbing is 22, HVAC is 23, electrical is 26.
- Divisions 31 to 33: site work. Earthwork is 31, exterior improvements is 32, utilities is 33.
How to read a section number
A section number has three pairs of digits. The first pair is the division. The next two pairs narrow the subject. Section 11 66 23 is Gymnasium Equipment. The 11 means Division 11, Equipment. The 66 means athletic equipment. The 23 means gymnasium equipment.
A section title that ends in 00 is usually broader than one that ends in a specific number. Architects choose how narrow to go. One job can put all athletic equipment in one section. Another job can split it into several.
What this means for a bid
- Your work can sit in more than one section. Search by title, not only by number.
- Architects sometimes use custom numbers. Check the table of contents.
- A section number in a bid invitation tells you what the general contractor expects from you.
- Related work in another division can change your scope. Blocking, power and supports are common examples.
Bid documents · Updated 11 Nov 2026