CSI MasterFormat divisions: the working reference

MasterFormat (maintained jointly by CSI and CSC — it's a Canadian standard as much as an American one) organizes specifications into numbered divisions, each holding sections numbered DD SS SS. Two working rules before the list: your scope is never entirely inside "your" division — Division 01 binds everyone, and cross-division items (your access hatch in their wall) are routine; and read codes as families — a spec's "07 26 16" belongs to the "07 26" family whether your reference list carries the exact code or not.

Procurement and general

Div.	Title	Estimator's note
00	Procurement and Contracting Requirements	Bid forms, instructions to bidders, contract conditions. The deal-breakers live here — read before pricing anything
01	General Requirements	Binds every trade: temporary services, cleaning, closeout, testing, protection. The seven costly clauses →

Facility construction (02–14)

Div.	Title	Estimator's note
02	Existing Conditions	Demolition, abatement designations, investigation reports — renovation money and renovation risk
03	Concrete	CIP, precast, toppings; exposure classes and FF/FL live here (with CSA A23.1 doing the governing)
04	Masonry	Unit masonry, veneer, mortar and accessories
05	Metals	Structural steel, joists, deck — and 05 50 misc. metals, the classic scope-boundary dispute zone
06	Wood, Plastics and Composites	Rough carpentry, blocking and backing (everyone's problem), millwork
07	Thermal and Moisture Protection	Roofing, waterproofing, insulation, air barriers, firestopping, sealants — the building-envelope catch-all
08	Openings	Doors, frames, hardware, glazing, curtain wall
09	Finishes	Drywall, ceilings, flooring, paint — and the substrate-prep clauses that reach back into Division 03
10	Specialties	Partitions, lockers, signage — small sections, easy to miss, someone has to carry them
11	Equipment	Owner equipment with trade-supplied bases, backing and rough-in — coordination items breed here
12	Furnishings	Usually NIC, but check who anchors and who patches
13	Special Construction	Pre-engineered buildings, pools, vaults — self-contained scopes with tentacles
14	Conveying Equipment	Elevators and hoists — plus the pits, rails and machine-room work other trades carry for them

Facility services (21–28)

Div.	Title	Estimator's note
21	Fire Suppression	Sprinklers and standpipes
22	Plumbing	—
23	HVAC	The thickest division on most institutional jobs
25	Integrated Automation	Building controls — watch the boundary with 23 and 26
26	Electrical	Power and lighting; the starter/VFD/disconnect ownership question vs. Division 23 is a perennial leveling dispute
27	Communications	Structured cabling, AV
28	Electronic Safety and Security	Fire alarm, access control, cameras

Site and infrastructure (31–35)

Div.	Title	Estimator's note
31	Earthwork	Excavation, backfill, shoring — read alongside the geotech report, which is the real bid document
32	Exterior Improvements	Paving, curbs, landscaping — the sitework/building-trade boundary lives here
33	Utilities	Site services to the building line

Process divisions (40–48)

Industrial work — process piping (40), material handling (41), process heating/cooling (42), gas and liquid handling (43–46), electrical power generation (48). Most ICI building tenders never open these; industrial ones live in them. If your building tender cites a 40-series section, read it — it usually means owner process equipment with trade interfaces.

The numbering traps

• Two eras. Pre-2004 MasterFormat used five digits and 16 divisions (03300 = cast-in-place concrete); the current edition uses six digits and the 00–48 structure. Owner in-house standards and older reference documents still carry five-digit codes — same families, different shape. Indexing a manual that mixes both →
• The moved divisions. The classics that changed homes in 2004: mechanical's old Division 15 became 21–23, electrical's old 16 became 26–28. An older estimator's "Div 15/16" and a current spec's "Div 21–28" are the same conversation.
• Reserved gaps. Divisions like 15–20, 24, 29–30 and others are reserved — a spec using one is either an owner's custom structure or an error, and either way worth a closer look.
• Section-level scope beats division-level scope. Bidding "Division 9" is how drywall ends up priced by the flooring sub. Real scope statements name section families — which is also how modern tools (ours included) filter what gets read.