Minutes of the BS-8 kick-off meeting at LBNL

7 August 2000

**Participants:** Vlado Bazjanac (VB), Fred Buhl (FB), Dru Crawley (DC),
Jim Forester (JF), Krishnan Gowri (KG), Phil Haves (PH), Rob Hitchcock
(RH), Veijo Lappalainen (VL), Mary Ann Piette (MP), Kent Reed (KR),
Richard See (RS), Steve Selkowitz (SS), Fred Winkelmann (FW).

**Strategic issues**

Multiple inheritance:

-   Fast-tracking will dictate the use of single inheritance (RH)

-   Model HVAC extension schemata with multiple inheritance, fast-track
    individual systems with single (VB)

-   Multiple inheritance can be implemented by aggregating single
    inheritances (JF)

-   No tools exist currently that will force a multiple inheritance into
    a single inheritance model (JF)

-   Provide evidence of potential benefit from multiple inheritance
    modeling in BS-8 to strengthen the case for the use of multiple
    inheritances throughout the IFC object data model (VB)

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-   Single inheritance in the IFC object data model has made the
    translation to XML easier (RS)

-   BLIS partners have not discussed multiple inheritance much (RS)

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-   The need for multiple inheritance will be determined in the course
    of work on BS-8 (KR & JF)

Connectivity:

-   The draft connectivity schema that was not included in IFC 2.0 and
    2x is on the right track (KR)

-   Loose ends from IFC 2.0 are cleaned up in IFC 2x, but the latter
    includes no new parts (JF)

-   Develop examples of connectivity and discuss what needs to be done
    via e-mail (all)

-   Separate topology from geometry and find out if more topology is
    needed (KR)

-   Topology is defined in the SHAPE schema, connectivity in
    SharedBuildingResources (JF)

-   Ask implementers about experiences in using connectivity (JF & VB)

Time series (consult JF's presentation in file
*Ifc_time_series_forester.ppt*):

-   Time series involve the tracking of a single data unit over time
    (JF)

-   Include time series in the basic definition of units (JF)

-   Time series were pulled out of IFC 2.0 (and never put in IFC 2x) for
    lack of review and implementers' interest (JF)

-   Interpretation of tabular data is currently subject to implementers'
    agreements and interpretation (JF)

-   Data bases involving time series are huge in size (KR, JF & VB)

-   Frank Olken apparently chose ORACLE as the data base software for
    BLISS because of the size issue (RH)

-   ORACLE's time series will not be adequate (KR)

-   Involve Frank Olken and the guy (?) from Georgia Tech when
    considering data base issues (JF)

-   Consider only time series that are simple; complex series are way
    too large for any known data base (JF)

-   Check out the work of the Modellica Alliance (JF)

-   Simulation input and output information are both time series (DC &
    FW)

-   Match output value with input value(s) that cause(s)/influence(s)
    the output value (RH)

-   Capturing simulation results and output in time series should have
    the first priority (VB)

-   Output time series are not enough for post-calculation tools, as
    input and parameter data are often needed to calculate performance
    figures (VL)

-   The definition of input time series (schedules and weather) should
    be subject to available resources (all)

-   Schedules must be included in the HVAC extension schemata (DC)

-   The most important criterion for inclusion in the HVAC extension
    schemata is what is needed for useful interoperability (VB)

-   The compatibility between measured and simulated data should be
    achieved in modeling time series; this will allow to take into
    account existing models of Building Automation Systems, BACnet trend
    log object, and/or history files of SCADA systems (VL)

XML:

-   Visio is increasing the support of HVAC diagramming by adding
    behavior and new shapes (RS)

-   Only a few CAD applications (ArchiCAD and Keops) are known to
    support HVAC objects (RS)

-   Timberline has a library of standard HVAC components for costing
    (RS)

-   Some BLIS applications will receive only XML data (RS)

-   The BLIS XML schema (a transcription of IFC 2.0) and tools will be
    open and available in October 2000 (RS)

-   XML tools capable of dealing with any EXPRESS schema already exist
    (RS)

-   The SECOM XML tool is late-bound (RS)

-   It is not clear if results from SECOM and STEP-based XML tools
    (Part 28) are the same (KR & RS)

-   Announce plans to publish HVAC XML schemata (SS)

-   Focus on the EXPRESS model first, then expand XML tools to
    incorporate HVAC definitions (VB)

**Scope of work**

HVAC in E+ (consult FB's presentation in file
*building_systems_simulation_buhl.ppt*):

-   The E+ team is still discussing packaged systems (FB)

-   Some of the "special" input objects (such as schedules and
    performance curves) should be modeled by BS-8, others (such as the
    topology of HVAC systems, connector lists and branches) should not
    (FB)

-   Component definitions are completely "flat" in E+ (FB)

-   Components are attached to circulation loops to add or subtract
    energy, change mass flow rate, or mix or split fluid streams (FB)

-   E+ has input and output data dictionaries that one has to fully
    comply with (FB)

-   The data dictionaries will be changed and expanded in the future
    (FB)

-   The data dictionaries currently do not include sub-typing (FB)

-   No primary and secondary loops can currently be coupled, as no
    secondary loops can be explicitly defined yet (FB)

-   E+ output can be very complex, as variable values can be reported at
    different times and time intervals (FB)

-   More components will be added before the final release of E+ 1.0,
    but nothing regarding controls will change (FB)

-   After the final 1.0 release the E+ team will examine what may have
    been done wrong (FB)

-   FB's PowerPoint slides can serve as a blue print for BS-8
    development (VB)

Processes to be supported in BS-8 (consult VB's presentation in file
*BS-8_project_summary_VB_Aug00.ppt*):

-   HVAC electrical data can be define only as attributes (JF & VB)

-   Review IFC 2x and request the addition of any electrical attributes
    that are needed and may be missing from the model (all)

-   Rearrange the list of supported processes considering

a)  what needs to be interoperable (VB)

b)  what is explicitly funded (VB)

c)  what is strongly supported by software such as FMMS, CMMS and cost
    estimation tools (PH & MP)

d)  what can stimulate external industry involvement and new
    partnerships (SS)

-   You\'ll recall I suggested that the processes that are supported by
    the HVAC IFCs should emphasize those that already have a strong
    software presence. For example, I consider c to have a good
    presence, plus cost estimation tools. But, commissioning does not
    have much of a software business to support.

BS-7 (consult VL's presentation in files *BS-7_extension.ppt* an*d
BS7_ObjectHierarchy.xls*):

-   Proposed changes to IFC 2.0 and 2x definitions include modifications
    and additions to classes IfcActuator, IfcController, IfcSensor,
    IfcDamper, IfcValve, and IfcFlowEquipment (VL)

-   BS-7 (IKE) is interested in converting P-sets into
    object/attribute/relationship sets and adding time series to BS-8
    (VB)

-   P-set nesting will go away if P-sets are converted into
    object/attribute/relationship sets (JF)

-   BS-7 has a proposal about what to convert into IFC classes and what
    to keep as P-sets that it will share (VL)

-   Single attribute changes can still be pushed into IFC 2x (JF)

-   BS-7 will request from MSG to include in IFC 2x the new attributes
    for existing P-sets, as well new object types and the related P-sets
    (VL)

-   Review Draft 4 of BS-7 to find if anything is missing and if any
    attributes should be added to IFC 2x (all)

**Project management**

BS-8 web page:

-   The project web page is up; it will be improved with additional
    information, graphic background, etc. (VB)

-   The project URL is *http://eetd.lbl.gov/btd/iai/bs8*

-   Access to the web page and project directories is public and open
    for reading (VB)

-   Writing is protected by username and password (VB)

-   Username is 'bs8body'

-   Call (510) 486-4092 for the password

Fast-tracking:

-   A single HVAC system schema (e.g. single duct VAV with vapor
    compression chillers) will have to include most of what other HVAC
    systems require; time compression and acceleration of deliverables
    hoped for from developing a schema for a single HVAC system type
    early will not be dramatic (PH)

Work plan:

-   Ask ASHRAE members to identify data types that are relevant in HVAC
    design and then preserve them in the model through commissioning
    (all)

-   Define equipment objects and submit definitions to ASHRAE TCs for
    review and comments (PH)

-   Review standard methods of specifying component performance outside
    the U.S. to ensure international applicability of BS-8 (PH)

-   Review non-manufacturer literature for component performance (all)

Who is going to do what:

-   IKE, VTT and Olof Granlund will decide what is the most useful part
    of BS-8 for them to pursue (all)

-   Develop an early scenario with BLIS group partners that will
    populate an IFC project model with geometry and some HVAC data and
    can then be used in cost estimating with Timberline software as well
    as in energy performance simulation with E+ (SS)

**Other issues**

Populating IFC project models:

-   HVAC design applications are missing (KR)

-   Determine the usefulness of the new HVAC additions in Visio 10 (PH)

-   Interoperability of E+ with other applications will reduce the need
    for a comprehensive GUI and the prospect of interoperability may
    make the development of a comprehensive GUI less attractive to 3^rd^
    party developers (PH)

-   Look at SIMSMART software from Canada; it is used by the U.S. Navy
    (KR)

# Action items

-   **URGENT** (by August 11): Review Draft 4 of BS-7 to find if
    anything is missing and if any attributes should be added to IFC 2x
    (PH, FB & KR)

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-   **URGENT** (by August 15): Review IFC 2x and request the addition of
    any electrical attributes that are needed and may be missing from
    the model (?)

-   Separate topology from geometry and find out if more topology is
    needed (KR)

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-   Ask implementers about experiences in using connectivity (VB)

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-   Announce plans to publish HVAC XML schemata (SS)