Comparing building classification systems III – Logic

After looking at the structure of popular building classification systems, now let’s look at their logic and internal consistency. For illustration, I’ll consider how they handle 4 different building elements.

First – what do you get when you search the different systems for a door?

OmniClass

Searching for “door” gives 192 results.

In the “Doors” subgroup of the “Openings, Passages and Protection Products” group. They’re classified based on their material (Metal Doors, Wood Doors) or function (Traffic Doors, etc.). At a deeper level of the table, doors are divided into more precise classes based on type of material or function: sliding, rotating, etc. But since wood doors, for example, are only classified based on how they open, it’s not clear how to specify an oak, pine or birch-wood door. Plastic doors, though, are classified based on coating, consistency and function. In short, the criteria for identifying objects and putting them in classes are not clear.

23-17 00 00	Openings, Passages, and Protection Products
23-17 11 00		Doors
23-17 11 11			Door Components
23-17 11 11 11				Door Frames
23-17 11 11 13				Preassembled Door and Frame Units
23-17 11 11 15				Door Fanlights
23-17 11 11 17				Door Sections
23-17 11 11 17 11					Structural Door Sections
23-17 11 11 17 13					Door Cladding Sections
23-17 11 11 19				Door Linings and Boards
23-17 11 11 21				Door Renovation Sets
23-17 11 11 23				Door Sidelites
23-17 11 11 25				Door Accessories
23-17 11 11 25 11					Door Peep Holes
23-17 11 11 25 13					Door Buffers
23-17 11 11 25 15					Door Stops
23-17 11 11 25 17					Door Mail Openings
23-17 11 11 25 19					Door Mail Slots
23-17 11 11 25 21					Door Louvers
23-17 11 11 25 23					Door Lights
23-17 11 13			Metal Doors
23-17 11 13 11				Hollow Metal Doors
23-17 11 13 13				Aluminum Doors
23-17 11 13 13 11					Aluminum Screen Doors
23-17 11 13 13 13					Aluminum Storm Doors
23-17 11 13 15				Steel Doors
23-17 11 13 15 11					Steel Screen Doors
23-17 11 13 15 13					Steel Storm Doors
23-17 11 13 17				Bronze Doors
23-17 11 13 19				Sliding Metal Doors
23-17 11 13 21				Folding Metal Doors
23-17 11 13 23				Revolving Metal Doors
23-17 11 13 25				Overhead Metal Doors
23-17 11 13 25 11					Roller Shutter Overhead Metal Doors
23-17 11 13 25 13					Sectional Overhead Metal Doors
23-17 11 15			Wood Doors
23-17 11 15 11				Carved Wood Doors
23-17 11 15 13				Flush Wood Doors
23-17 11 15 15				Clad Wood Doors
23-17 11 15 17				Prefinished Wood Doors
23-17 11 15 19				Stile and Rail Wood Doors
23-17 11 15 21				Wood Storm Doors
23-17 11 15 23				Wood Screen Doors
23-17 11 15 25				Sliding Wood Doors
23-17 11 15 27				Folding Wood Doors
23-17 11 15 29				Revolving Wood Doors
23-17 11 15 31				Overhead Wood Doors
23-17 11 15 31 11					Roller Shutter Overhead Wood Doors
23-17 11 15 31 13					Sectional Overhead Wood Doors
23-17 11 17			Plastic Doors
23-17 11 17 11				Laminated Plastic Doors
23-17 11 17 13				Solid Plastic Doors
23-17 11 17 15				Plastic Storm Doors
23-17 11 17 17				Plastic Screen Doors
23-17 11 17 19				Sliding Plastic Doors
23-17 11 17 21				Folding Plastic Doors
23-17 11 17 23				Revolving Plastic Doors
23-17 11 17 25				Overhead Plastic Doors
23-17 11 17 25 11					Roller Shutter Overhead Plastic Doors
23-17 11 17 25 13					Sectional Overhead Plastic Doors
23-17 11 19			Composite Doors
23-17 11 19 11				Fiberglass Composite Doors
23-17 11 19 13				Sliding Composite Doors
23-17 11 19 15				Folding Composite Doors
23-17 11 19 17				Composite Hinged Doors
23-17 11 19 19				Revolving Composite Doors
23-17 11 19 21				Overhead Composite Doors
23-17 11 19 21 11					Roller Shutter Overhead Composite Doors
23-17 11 19 21 13					Sectional Overhead Composite Doors
23-17 11 21			Glazed Doors
23-17 11 21 11				Glazed Hinged Doors
23-17 11 23			All Glass Doors
23-17 11 23 11				Swinging All Glass Doors
23-17 11 23 13				Sliding All Glass Doors
23-17 11 23 15				Folding All Glass Doors and Grilles
23-17 11 23 15 11					Accordion Folding All Glass Doors
23-17 11 23 15 13					Panel Folding All Glass Doors
23-17 11 23 15 15					Bifold All Glass Doors
23-17 11 23 17				Revolving All Glass Doors
23-17 11 23 19				Balanced All Glass Doors
23-17 11 25			Passage Grilles
23-17 11 25 11				Sliding Passage Grilles
23-17 11 25 13				Folding Passage Grilles
23-17 11 25 13 11					Accordion Folding Passage Grilles
23-17 11 25 15				Rolling Grilles
23-17 11 27			Access Doors
23-17 11 27 11				Trap Doors
23-17 11 27 13				Access Doors
23-17 11 27 15				Floor Hatches
23-17 11 27 17				Roof Hatches
23-17 11 27 19				Security Floor Hatches
23-17 11 27 21				Security Roof Hatches
23-17 11 27 21 11					Forced Entry and Ballistic Resistant Roof Hatches
23-17 11 27 21 13					Ballistic Resistant Roof Hatches
23-17 11 27 23				Man Hole Accesses
23-17 11 29			Access Panels
23-17 11 29 11				Equipment Access Panels
23-17 11 31			Fire Doors
23-17 11 31 11				Fire Rated Doors
23-17 11 31 11 11					Fire Rated Overhead Doors
23-17 11 31 11 13					Fire Rated Rolling Doors
23-17 11 31 11 15					Fire Rated Sliding Doors
23-17 11 31 11 17					Fire Rated Hinged Doors
23-17 11 31 11 19					Fire Rated Revolving Doors
23-17 11 31 13				Temperature Rate of Rise Fire Doors
23-17 11 31 13 11					Temperature Rate of Rise Fire Rated Overhead Doors
23-17 11 31 13 13					Temperature Rate of Rise Fire Rated Rolling Doors
23-17 11 31 13 15					Temperature Rate of Rise Fire Rated Sliding Doors
23-17 11 31 13 17					Temperature Rate of Rise Fire Rated Hinged Doors
23-17 11 31 13 19					Temperature Rate of Rise Fire Rated Revolving Doors
23-17 11 35			Fire Shutters
23-17 11 37			Controlled Environment Doors
23-17 11 37 11				Cold Storage Doors
23-17 11 37 13				Sound Control Doors
23-17 11 37 15				Radiation Protection Doors
23-17 11 37 15 11					Electromagnetic Shielding Doors
23-17 11 37 15 13					Radio Frequency Protection Doors
23-17 11 37 15 15					BO Shielding Doors
23-17 11 37 15 17					X Ray Protection Doors
23-17 11 37 15 19					Nuclear Radiation Protection Doors
23-17 11 37 15 21					High Energy Magnetic Pulse Protection Doors
23-17 11 39			Detention Doors
23-17 11 41			Hanger Doors
23-17 11 43			Lightproof Doors
23-17 11 43 11				Revolving Darkroom Door
23-17 11 45			Traffic Doors
23-17 11 45 11				Flexible Traffic Doors
23-17 11 45 13				Flexible Strip Doors
23-17 11 45 15				Rigid Panel Traffic Doors
23-17 11 45 17				Rapid Opening Doors
23-17 11 47			Pressure Resistant Doors
23-17 11 47 11				Airtight Doors
23-17 11 47 13				Watertight Doors
23-17 11 49			Security Rated Door
23-17 11 49 11				Blast Resistant Doors
23-17 11 49 13				Forced Entry Door
23-17 11 49 13 11					Multi Forced Entry Lock Door
23-17 11 49 13 13					Single Forced Entry Lock Door
23-17 11 49 15				Forced Entry and Ballistic Resistant Door
23-17 11 49 17				Ballistic Resistant Door

Uniclass 2015

Searching for “door” gives 102 results, within the openings group of elements. In Uniclass 2015, just like in OmniClass, multiple different classification criteria are used in the table: doors are classified according to the material they’re made of, how they work, their purpose, etc. So it’s hard to follow the classification logic and structure.

Pr_30_59_24	30	59	24		Doorsets
Pr_30_59_24_04	30	59	24	04	Automatic revolving doorsets
Pr_30_59_24_14	30	59	24	14	Collapsible gate and grille sets
Pr_30_59_24_15	30	59	24	15	Combination doorsets
Pr_30_59_24_16	30	59	24	16	Composite doorsets
Pr_30_59_24_28	30	59	24	28	Fire doorsets
Pr_30_59_24_30	30	59	24	30	Flexible doorsets
Pr_30_59_24_34	30	59	24	34	Glass reinforced plastics (GRP) doorsets
Pr_30_59_24_37	30	59	24	37	High security doorsets
Pr_30_59_24_38	30	59	24	38	High speed doorsets
Pr_30_59_24_48	30	59	24	48	Loading bay doorsets
Pr_30_59_24_49	30	59	24	49	Louvre doorsets
Pr_30_59_24_50	30	59	24	50	Manual revolving doorsets
Pr_30_59_24_52	30	59	24	52	Metal doorsets
Pr_30_59_24_64	30	59	24	64	Polyvinyl chloride (PVC) strip curtain sets
Pr_30_59_24_75	30	59	24	75	Sectional overhead doorsets
Pr_30_59_24_80	30	59	24	80	Sliding door and partition sets
Pr_30_59_24_81	30	59	24	81	Sliding folding doorsets
Pr_30_59_24_83	30	59	24	83	Sliding folding shutters
Pr_30_59_24_92	30	59	24	92	Unplasticized polyvinyl chloride (PVC-U) doorsets
Pr_30_59_24_93	30	59	24	93	Up-and-over doorsets
Pr_30_59_24_97	30	59	24	97	Wood doorsets

ISO 81346

Searching for “door” in the 3rd table of ISO 81346-2 yields only 2 results: “doors” and “large doors”. This classification system does not apply any criteria for materials, function or operating principle. A door is simply a door.

In the ISO 81346 classification methodology, the properties of elements are taken out of the classification system. Things like type of material, fire-safety requirements, or manner of opening are traits of a door that make the element unique. Specifying an element’s traits as properties offers more freedom. There’s no limit to the number of properties, so defining them all in a classification system is impossible. But properties are easy to specify in your BIM software, where every element of a structure has its standard attributes (material, function, density, energy efficiency parameters, etc.). That data gets included in specification tables, and thus the element types are classified.

The second object for review is a window:

OmniClass

Windows, like doors, are part of the “Openings, Passages and Protection” group of elements in the table’s first level. Windows, too, are classified on the basis of the material they’re made of, their purpose, and functional criteria.

23-17 13 00	Windows
23-17 13 11		Window Components
23-17 13 11 11			Window Sections
23-17 13 11 13			Window Linings and Boards
23-17 13 11 15			Window Vents
23-17 13 11 17			Window Frames
23-17 13 11 19			Transoms
23-17 13 11 21			Sidelites
23-17 13 11 23			Retractable Screens
23-17 13 13		Metal Windows
23-17 13 13 11			Metal Fixed Windows
23-17 13 13 13			Metal Horizontal Sliding Windows
23-17 13 13 15			Metal Single Hung Windows
23-17 13 13 17			Metal Double Hung Windows
23-17 13 13 19			Metal Triple Hung Windows
23-17 13 13 21			Metal Awning Windows
23-17 13 13 23			Metal Casement Windows
23-17 13 13 25			Metal Hopper Windows
23-17 13 13 27			Metal Vertical Pivoted Windows
23-17 13 13 29			Metal Jalousie Windows
23-17 13 15		Wood Windows
23-17 13 15 11			Wood Fixed Windows
23-17 13 15 13			Wood Horizontal Sliding Windows
23-17 13 15 15			Wood Single Hung Windows
23-17 13 15 17			Wood Double Hung Windows
23-17 13 15 19			Wood Triple Hung Windows
23-17 13 15 21			Wood Awning Windows
23-17 13 15 23			Wood Casement Windows
23-17 13 15 25			Wood Hopper Windows
23-17 13 15 27			Wood Vertical Pivoted Windows
23-17 13 15 29			Wood Jalousie Windows
23-17 13 17		Plastic Windows
23-17 13 17 11			Plastic Fixed Windows
23-17 13 17 13			Plastic Horizontal Sliding Windows
23-17 13 17 15			Plastic Single Hung Windows
23-17 13 17 17			Plastic Double Hung Windows
23-17 13 17 19			Plastic Triple Hung Windows
23-17 13 17 21			Plastic Awning Windows
23-17 13 17 23			Plastic Casement Windows
23-17 13 17 25			Plastic Hopper Windows
23-17 13 17 27			Plastic Vertical Pivoted Windows
23-17 13 17 29			Plastic Jalousie Windows
23-17 13 17 31			Plastic Jalousie Awning Windows
23-17 13 19		Composite Windows
23-17 13 19 11			Composite Fixed Windows
23-17 13 19 13			Composite Horizontal Sliding Windows
23-17 13 19 15			Composite Single Hung Windows
23-17 13 19 17			Composite Double Hung Windows
23-17 13 19 19			Composite Triple Hung Windows
23-17 13 19 21			Composite Awning Windows
23-17 13 19 23			Composite Casement Windows
23-17 13 19 25			Composite Hopper Windows
23-17 13 19 27			Composite Vertical Pivoted Windows
23-17 13 19 29			Composite Jalousie Windows
23-17 13 19 31			Composite Jalousie Awning Windows
23-17 13 21		Projecting Windows
23-17 13 21 11			Bay Windows
23-17 13 21 11 11					Angles Bay Windows
23-17 13 21 11 13					Box Bay Windows
23-17 13 21 13			Bow Windows
23-17 13 23		Roof Windows
23-17 13 25		Masonry Windows
23-17 13 25 11			Glass Masonry Unit Windows
23-17 13 27		Special Purpose Windows
23-17 13 27 11			Fire Rated Windows
23-17 13 27 13			Detention Windows
23-17 13 27 15			Pass Windows
23-17 13 27 17			Controlled Environment Windows
23-17 13 27 17 11					Sound Control Windows
23-17 13 27 17 13					Radiation Protection Windows
23-17 13 29		Security Windows
23-17 13 29 11			Ballistic Resistant Windows
23-17 13 29 11 11					Teller Forced Entry and Ballistic Resistant Windows
23-17 13 29 13			Blast Resistant Windows
23-17 13 29 13 11					Blast Resistant Structural Muntin Windows
23-17 13 29 13 13					Blast Resistant Window Frames
23-17 13 29 15			Impact Resistant Windows
23-17 13 29 17			Forced Entry Resistant Windows
23-17 13 29 19			Radio Frequency Shielding Windows
23-17 13 29 21			Security Window Films
23-17 13 29 21 11					Shatter Resistant Security Window Films
23-17 13 29 23			Security Window Curtains
23-17 13 29 23 11				Security Window Blast Curtains

Uniclass 2015

Unlike for doors, for windows the only main classification criteria is the material they’re made of.

Pr_30_59_98	30	59	98		Window units
Pr_30_59_98_02	30	59	98	02	Aluminium window units
Pr_30_59_98_03	30	59	98	03	Aluminium frame roof window units
Pr_30_59_98_15	30	59	98	15	Composite window units
Pr_30_59_98_34	30	59	98	34	Glass louvre window units
Pr_30_59_98_72	30	59	98	72	Rigid polyurethane frame roof window units
Pr_30_59_98_83	30	59	98	83	Steel window units
Pr_30_59_98_84	30	59	98	84	Steel frame roof window units
Pr_30_59_98_92	30	59	98	92	Unplasticized polyvinyl chloride (PVC-U) window units
Pr_30_59_98_93	30	59	98	93	Unplasticized polyvinyl chloride (PVC-U) roof window units
Pr_30_59_98_96	30	59	98	96	Wood window units
Pr_30_59_98_97	30	59	98	97	Wood frame roof window units

ISO 81346

Here too a search of the system gives us only 2 results: “window” and “window unit”. As noted, their properties (material, function, manner of operating) are assigned using BIM software.

Next we’ll consider a beam:

OmniClass

Beams are spread out over various groups. They are classified on the basis of their purpose and their type.

Uniclass 2015

Beams are found in the “Structure and general products” group, in the “Support and restraint products” subgroup. As with windows, the main classification criteria for beams is the material and beam type.

ISO 81346

Searching for “beam” in the third table here gives only 1 result: “beam”. Since in this classification system property criteria are not used, classification becomes simpler and at the same time clearer.

Finally, for more variety, let’s take an engineering element, say a pipe:

OmniClass

Most relevant elements are in the “General facility services products” group’s “Piping” subgroup. The main criteria for grouping is whether pipes are single- or double-walled, and classification at the 4^th level is for use aboveground or underground.

Uniclass 2015

In the U.K. classification system almost all pipes are classified on the basis of two criteria: material and manner of use. But the mixing of these criteria creates more confusion than clarity.

ISO 81346

Searching for “pipe” in the third table of the international standard gives 2 results: an open-ended channelling element, or “drainpipe”, and a closed-ended channelling element – simply a “pipe”.

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