Table 4 Inventories/processes as column vectors in LCI analysis of a marine main engine
(2) Fuel oil A: The Pre 4 database was quoted [6].
(3) Argon gas: Argon gas is a secondary product in production stage of O2 gas. So, it was assumed that inventory data of argon gas is equivalent to those of O2 gas.
(4) Steel plates: The data added the process data of hot rolling to the inventory data of steel ingot in the NIRE Database were used [7] [8].
(5) Purchased finished equipments/other parts: All the purchased finished equipments and other parts were assumed to be equivalent to forged steel parts.
Manufacturing processes were treated as follows. For normalization of the process flows, following functional unit of each manufacturing process was determined respectively.
Cutting weight was regarded as the functional unit of machining work, since the work seems to be proportional to steel scrap discharged in the machining process. Deposited metal weight was regarded as the functional unit of welding work, since the work is proportional to welding electrode used in the welding process. Assembling time was regarded as the functional unit of assembling work. Assembling work was evaluated in assembling time, which was regarded as the functional unit of assembling work. The authors estimated the assembling time on the basis of the man-hour data, assuming that part assembling and whole assembling were done by three and eight workers respectively. Land trial time was regarded as the functional unit of land trial work.
Quantities in the functional unit of the manufacturing processes are shown in Table 5.
