. 2020 Oct 7;20(19):5708. doi: 10.3390/s20195708

Table 3.

Discount factors and lifetime of maintenance actions.

Actions	Discount Factors	Lifetime
Do nothing	$d f_{d o_n o t h i n g} = 1$	-
Batch Corrosion Inhibition	$d f_{i n h i b i t o r} = 1 - 0.9487 e^{- 0.023 \times i n h i b i t o r_l i f e t i m e}$	1 month [33]
Internal coating	$d f_{c o a t i n g} = 0$	5 years [24]
Pigging	$d f_{p i g g i n g} = 0$	2 weeks [33]