Total Routine Losses formula |
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| \( L_t \;=\; L_s + L_w \) | ||
| Symbol | English | Metric |
| \( L_t \) = Total Routine Losses | \(lbf \;/\; yr\) | \(Pa\) |
| \( L_s \) = Standing Losses | \(lbf \;/\; yr\) | \(Pa\) |
| \( L_w \) = Working Losses | \(lbf \;/\; yr\) | \(Pa\) |
Total routine losses, abbreviated as \(L_t\), from fixed roof tanks is the cumulative volume of liquid or vapor lost from storage tanks with a fixed, non-moving roof due to regular operational activities. These losses primarily occur through evaporation, breathing (venting), and working losses.
Evaporation losses happen when volatile liquids, such as petroleum products or chemicals, vaporize and escape through the tank's vents or seals due to temperature changes or atmospheric conditions. Breathing losses, also called standing storage losses, occur when the tank's internal pressure changes due to daily temperature fluctuations, causing the tank to "breathe" by expelling vapor or drawing in air. Working losses are associated with the filling or emptying of the tank, where vapor is displaced and released as liquid is added or withdrawn. The total routine losses depend on factors like the tank's design, the volatility of the stored liquid, local climate, and operational practices.
