Page 59 - Impiantistica industriale Luglio Agosto 20147

with different rankings and risk levels. On this
basis a third, even more detailed, study was
carried out to defne the concept to be imple-
mented during the FEED (Front End Engineering
Design) and EPC (Engineering Procurement
Construction) phases of the project (fgure 4).

Modularization strategy:
from the concept
to the preassembly
Fig. 4 – Modularization decision qualifed pre-fabrication yards and the strategy
process for the material delivery, and fnally, with the implementation plan
construction manager, he discussed a possible The consequences of modularization infuence
installation sequence based on constructability all the key project decisions in terms of design,
studies (fgure 3). construction, purchasing, subcontracting stra-
tegies, planning and cost control. When this
During the frst step, the modularization solution is defned and applied this represents
a non-return point for the entire project, unless
team evaluated the feasibility of the heavy recycle and impact on the execution pro-
approach, mainly assessing the labor gram are considered acceptable. So, once the
(differential rates, productivity and concept was defned after the studies executed
experience) and site attributes during the early stages of the job, a comprehen-
sive preassembling plan was been prepared
(climate, remoteness and access) and implemented.
The starting point was the preparation of a
summary document called Modularization and
During the frst step, the modularization team Preassembling Philosophy whose content re-
evaluated the feasibility of the approach, mainly presented the fundamental background for any
assessing the labor (differential rates, producti- choice taken during
vity and experience) and site attributes (climate, the execution of the
remoteness and access). This stage occurred project. This document The consequences
very early in the project when only basic infor- basically summarizes of modularization
mation was available and encompassed a high the conclusion of pre- infuence all the key
level review of key factors. The modularization vious studies and the project decisions
team then started the screening study. general guidelines for
the detailed design of in terms of design,
modules and preas- construction,
sembled units (fgu- purchasing,
re 5). Transfer of this subcontracting
concept and the asso- strategies, planning
ciated implementation
models into precise and cost control
instructions has been
carried out interactively,
generating frstly a basic deliverable Engineering
Design Basis and, fnally, the essential Enginee-
ring Detailed Instructions (fgure 6).
This latter document provided each ET with cle-
ar indications about module types, interconnec-
tions between adjacent modules and with the
foundation baseplates, testing recommenda-
Fig. 5 - Typical heat exchangers This second step took place when suffcient tions and design considerations. Also it includes
structure included in Modularization details were available to develop a cost and the principles for the preparation of subcontract
and Preasembling Philosophy schedule comparison between “stick-built” requisitions through which consortium intends
(conventional approach) and different levels of to allocate the module assembly scope to one
modularization. Preliminary layouts and module or more prefabrication companies.
confgurations have also been compared. The The preparation of this deliverable required si-
result was the selection of different scenarios gnifcant input from the key engineering discipli-

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