Exchange Cost Model - Preliminary Appraisal

Project Stage

Stage	Name	Valid
0	Portfolio requirements
1	Conception of need
2	Outline feasibility
3	Substantive feasibility
4	Outline conceptual design
5	Full conceptual design
6	Coordinated design and procurement
7	Production information
8	Construction
9	Operation and maintenance
10	Disposal

Overview

Please ensure that you have read the process mapping document 'pm_cost_modelling' before proceeding with this exchange requirement.

The scope of this exchange requirement is cost modelling stage 2 - Preliminary Appraisal.
That is, the cost model is essentially based on the floor area of the building with the floor area being determined by the addition of the area at each building storey; which means that the building storeys must also be defined.

An example scenario for this stage is shown in the table below:

This exchange requirement assumes that a conceptual building model has been defined and that relevant information can be obtained from shape representations that it contains.
During this stage the information available is limited to the following requirements:

• a building is defined in terms of its shape and the number of building storeys that it contains (or is expected to contain)
• it should be of a particular type of construction that can be identified as broadly equivalent to some other type of construction used on a previous project and whose init cost information is known.
• it should be located in a particular place and on a particular site
• there are factors that affect the 'preliminary appraisal' cost including (but not limited to) items such as
  • expected building configuration (e.g. multi-storey as opposed to single storey)
  • expected structural complexity based on ground conditions
  • expected level of servicing for operational and comfort purposes
  • accessibility of the location
  • labor resource availability

Particular information that is required to determine 'preliminary appraisal' cost includes:

• the name of the project (for identification purposes) and the units generally used throughout the project;
• the current stage of the project; whilst this is generally optional, it should be mandatory for this exchange requirement
• the location and expected area of a site on which a building is to be located (the shape representation of a site is not necessary for this Exchange Requirement)
• the building or buildings for which the cost is required (at least one building must be specified although the shape representation of a building is not necessary for this Exchange Requirement)
• the building storeys within the building together with their area (although the shape representation of a building storey is not necessary for this Exchange Requirement)
• the area, volume or size factor of the building
• values for factors that may affect the cost
  • factors may be applied to the building directly or individually determined
  • e.g. services costs may be on a volume or size factor basis
• classification of objects for collection into groups and assemblies for costing purposes

Information Requirements

Context	Information Needed	MAN	REC	OPT	Actor Supplying	Functional Part
Precursor	The provisions of the exchange requirement er_exchange_building_model (concept) must be satisfied				Building Design	er_exchange_building_model (concept)
Building (Area Quantities)	Area quantities should be given for the building to enable cost modelling.				Building Design OR Cost Modelling	fp_define_quantity (area)
Building (Volume Quantities)	Volume quantities should be given for the building to enable cost modelling.				Building Design OR Cost Modelling	fp_define_quantity (volume)
Building (Cost)	Unit cost information should be assigned to the building to enable total cost to be determined.				Building Design OR Cost Modelling	fp_associate_cost
Building Storey (Area Quantities)	Area quantities should be given for the building storey(s) to enable cost modelling.				Building Design OR Cost Modelling	fp_define_quantity (area)
Building Storey (Volume Quantities)	Volume quantities should be given for the building storey(s) to enable cost modelling.				Building Design OR Cost Modelling	fp_define_quantity (volume)
Cost Impact Factors	Various factors may be provided for the element groups to identify their expected impact on the approximate estimate cost in comparison with reference costs.				Building Design OR Cost Modelling	fp_define_quantity (count)
Cost Item (Measured)	A cost item should be defined for each element group. The cost item brings together the quantity of the group, the unit cost for the group and all the relevant cost factors and provides a result that is an overall cost value.				Cost Modelling	fp_model_cost_item
Cost Item (Ancillary)	Cost items that deal with specifically assigned costs such as preliminaries, external works, contingencies etc. should be individually identified and assigned to the 'head' object in the model to be used for costing. Typically, this is expected to be the project.				Cost Modelling	fp_model_cost_item
Cost Schedule	Costs and quantities may be collected together into cost items and ultimately into a cost schedule for further work.				Cost Modelling	fp_model_cost_schedule

Results

Result type (FP/ ER/ Document/ PSet/ Specification etc.)	Information Provided	MAN	REC	OPT	Actor Receiving	Result Identifier
Model	Model of proposed building with preliminary appraisal costs associated with appropriate objects.				Building Design Client
Schedule	A schedule of costs with cost items broken down into line items, cost groups and cost parts.				Building Design Client