A Model for the Assessment of the Water Footprint …
67
1.2 Economic Evaluation: Budgeting Model
In the construction sector, the work-breakdown system (WBS) or classification
system are the dominant management tools. All these bases are proposed as an
ideal tool for the accomplishment of the economic quantification or budgeting and
also as an integrating element since its system of decomposition and hierarchization makes it possible to introduce a standardized process. The basic concept in all
these systems is to divide a complex problem (project) into increasingly simple parts
(units), and these, in turn, are decomposed into the resources needed for its development (basic prices) which are easier to analyze and study, and then all these parts can
be added together, without overlap or repetition to define the complex development
of the construction project. This cost structure allows a transparent cost estimate
to be made at a stage prior to execution, treating the information in a personalized
manner according to the objectives to be achieved.
The proposal developed here can be valid for any Construction Cost Base, but,
the Systematic Classification used by the Andalusian construction cost database [8]
has been used, thus betting on a flexible and adaptable system, with a precise identification of the work units, which allows the uniform elaboration of budgets and
which presents a high level of implementation, use and acceptance in the geographical environment of the project. It is used in public housing works by the Andalusian Government and this organization promotes its development and continuous
updating. This consists of a model for estimating the costs of projected works by
considering execution costs (direct and indirect). An alphanumeric coding allows a
precise identification because there is a mandatory biunivocal relationship, that is,
each code has only one concept and each concept has only one code.
Direct costs (DC) are all those expenses relating to materials, labour, machinery
and installations that are involved in the execution of a specific unit of work and are
directly attributable to it by allocating the necessary yields and quantities of each
of them. Indirect costs (IC) are all those expenses that cannot be directly allocated
to specific units, and which will be passed on by means of an equal percentage of
the DC for all units. The ICs include indirect labour dedicated to control and work
organization functions, auxiliary means that are not part of a single work unit, the
temporary work facilities. Its estimated calculation, in advance, requires a detailed
and detailed analysis of the various factors that can influence the determination of
the same as the type of work (new plant, recovery), the geometry and immediate
environment of the site, the type of building, the programming of its implementation
in time, organization and methods of work on site.
Depending on the level of detail sought, the elements of the cost model can
be classified by grouping the cost classes into different levels with more or less
development in the form of a pyramid, see Fig. 2, in the base are the supply prices
(SUP) determined by the manufacturer in accordance with the conditions of supply
and receipt of the materials,below are the basic prices (BP) which include together
with the SUP the collection and losses of material, distributed mainly according to
the three natures mentioned: materials, machinery and labour; in the next level are the
67
1.2 Economic Evaluation: Budgeting Model
In the construction sector, the work-breakdown system (WBS) or classification
system are the dominant management tools. All these bases are proposed as an
ideal tool for the accomplishment of the economic quantification or budgeting and
also as an integrating element since its system of decomposition and hierarchization makes it possible to introduce a standardized process. The basic concept in all
these systems is to divide a complex problem (project) into increasingly simple parts
(units), and these, in turn, are decomposed into the resources needed for its development (basic prices) which are easier to analyze and study, and then all these parts can
be added together, without overlap or repetition to define the complex development
of the construction project. This cost structure allows a transparent cost estimate
to be made at a stage prior to execution, treating the information in a personalized
manner according to the objectives to be achieved.
The proposal developed here can be valid for any Construction Cost Base, but,
the Systematic Classification used by the Andalusian construction cost database [8]
has been used, thus betting on a flexible and adaptable system, with a precise identification of the work units, which allows the uniform elaboration of budgets and
which presents a high level of implementation, use and acceptance in the geographical environment of the project. It is used in public housing works by the Andalusian Government and this organization promotes its development and continuous
updating. This consists of a model for estimating the costs of projected works by
considering execution costs (direct and indirect). An alphanumeric coding allows a
precise identification because there is a mandatory biunivocal relationship, that is,
each code has only one concept and each concept has only one code.
Direct costs (DC) are all those expenses relating to materials, labour, machinery
and installations that are involved in the execution of a specific unit of work and are
directly attributable to it by allocating the necessary yields and quantities of each
of them. Indirect costs (IC) are all those expenses that cannot be directly allocated
to specific units, and which will be passed on by means of an equal percentage of
the DC for all units. The ICs include indirect labour dedicated to control and work
organization functions, auxiliary means that are not part of a single work unit, the
temporary work facilities. Its estimated calculation, in advance, requires a detailed
and detailed analysis of the various factors that can influence the determination of
the same as the type of work (new plant, recovery), the geometry and immediate
environment of the site, the type of building, the programming of its implementation
in time, organization and methods of work on site.
Depending on the level of detail sought, the elements of the cost model can
be classified by grouping the cost classes into different levels with more or less
development in the form of a pyramid, see Fig. 2, in the base are the supply prices
(SUP) determined by the manufacturer in accordance with the conditions of supply
and receipt of the materials,below are the basic prices (BP) which include together
with the SUP the collection and losses of material, distributed mainly according to
the three natures mentioned: materials, machinery and labour; in the next level are the