Module: BTAP::StructureData

Included in:

Structure

Defined in:

lib/openstudio-standards/btap/structure.rb

Constant Summary

@@data =

@author: Denis Bourgeois

Building STRUCTURE parameters, ultimately driving BTAP definitions of e.g.

- internal mass
- envelope CLADDING/FRAMING/FINISH selection
- related thermal bridging calculations (and uprated insulation levels)
- costing
- embodied carbon tallies

As detailed a bit further on, this determination is either via user input:

- e.g. "clt" (mass timber) post/beam STRUCTURE, for a school.

Or auto-assigned based on the prevalence of model space type assignments:

- e.g. 75% of spaces are commercial in nature (see activity.rb),
  therefore the building STRUCTURE defaults to "steel" post/beam.

The overarching idea is that (in most cases) OpenStudio surface construction & material choices (in addition to internal mass definitions), mostly stem from underlying structural design choices (which aren’t natively defined in OpenStudio). Structural choices have more to do with fire safety, budget, durability & practicality (low-rise vs high-rise), local workforce, on-site vs prefab, etc.

Ensuring consistency between building STRUCTURE, envelope selection, internal mass definitions, etc. is key to harmonizing predicted energy use, peak demand assessments, GHG emissions, vs thermal resilience and embodied energy/GHG tallies.

— —- —- —- —- —- —- —- —- —- —- —- —- —- — # Although “wood” framed walls constitute the load-bearing components of a “wood” framed building STRUCTURE (e.g. low-rise housing), they can equally be found as non-load-bearing components in a “clt” post-beam STRUCTURE. Light gauge “steel” framed walls are much more common in a non-residential STRUCTURE (e.g. “steel” post/frame, “concrete” post & beam, and even “clt”), though rarely found in low-rise housing. Although one may observe some real-world mixing of STRUCTURE vs FRAMING in a building, it remains largely deterministic: designers select constructions (FRAMING, insulation) while taking building classification and STRUCTURE selection into consideration - the inverse is rarely true.

STRUCTURE   description
__________  ___________________________________________________________
"steel"     steel, post/frame (default)
"metal"     prefab panelized steel STRUCTURE (**, ++), typically 1 story
"concrete"  reinforced concrete, post/beam/slab
"cmu"       load-bearing concrete masonry unit walls, typically 1-story
"wood"      conventional load-bearing wood-framed and/or -engineered
"clt"       prefab, post/beam mass/cross-laminated/timber (**)

NOTES:

 **  Neither "metal" nor "clt" options can be considered as fully
     supported by BTAP, e.g.:
       - no range of admissible envelope Uo factors
       - no associated PSI-factors (thermal bridging)
       - no costing data
       - no embodied energy/carbon data
     They are nonetheless (minimally) maintained here as an
     "aide-mémoire" for future BTAP upgrades - @todo.

 ++  ASHRAE 90.1 2022 definitions of:

     "METAL BUILDING": a complete integrated set of mutually dependent
     components and assemblies that form a building, which consists of
     a steel-framed superSTRUCTURE and metal skin.

     "METAL BUILDING ROOF": a roof that:
     a. is constructed with a metal, structural, weathering surface;
     b. has no ventilated cavity; and
     c. has the insulation entirely below deck (i.e., does not include
        composite concrete and metal deck construction nor a roof
        FRAMING system that is separated from the superSTRUCTURE by a
        wood substrate) and whose STRUCTURE consists of one or more of
        the following configurations:
        1. Metal roofing in direct contact with steel FRAMING members
        2. Metal roofing separated from steel FRAMING by insulation
        3. Insulated metal roofing panels installed per (a) or (b)

     "METAL BUILDING WALL": a wall whose STRUCTURE consists of metal
     spanning members supported by steel structural members (i.e. does
     not include spandrel glass or metal panels in curtain wall systems).

Note that there’s a (growing?) need to contrast “metal” buildings against the default “steel” post/beam option. Like a “wood” framed STRUCTURE or a load-bearing “cmu” wall, a “metal” building’s envelope structure and skin are indistinguishable, i.e. no mixing/matching of STRUCTURE vs envelope.

There are of course several other (smaller scale) structural options, often load-bearing envelopes like adobe/hemp/straw bale construction. Most would agree that these are fairly rare occurrences - rare enough to avoid shortlisting them for commercial building stock assessments. One could state the same when it comes to the current (marginal) use of “clt”. Yet as the latter is rapidly becoming a robust low-carbon alternative to “steel” and “concrete” options, its inclusion is justified. Additional options may nonetheless be added in the future.

{structure: {}, cladding: {}, finish: {}, category: {}}

Class Method Summary

• .extended(base) ⇒ Object

Instance Method Summary

• #data ⇒ Hash

  Returns BTAP Structure data.

Class Method Details

.extended(base) ⇒ Object

# File 'lib/openstudio-standards/btap/structure.rb', line 246

def self.extended(base)
  base.send(:include, self)
end

Instance Method Details

#data ⇒ Hash

Returns BTAP Structure data.

Returns:

• (Hash) —

  BTAP Structure data

# File 'lib/openstudio-standards/btap/structure.rb', line 242

def data
  @@data
end