Tank Farm: Dyke Wall Height Calculation, Piping Layout for Tank Farm- Part 2Tankfarm part 1

      I.  Dyke Wall Height Calculation:

Area of Dyke                            :           21582.5 M2

Height of Dyke Assumed           :           ‘H’ = 1.2 MHeight of Foundation ‘h’ which is 0.9MDiameter of Foundation             :           ‘D’ = Diameter of Tank + 1.5 MNumber of Tanks                       :           ‘n’Fire wall dimensions                  :           200 MM Thk. X 600 MM HighDyke enclosure vol.                   ≥          Working capacity of Largest tank + Dead volumesA                      ≥                      B                                    +        CA) Dyke enclosure volume         =          Area of Dyke X Dyke Height=          21582.5         X       1.2         =25899 M3

B) Working capacityof Largest tank       =          17304 M3

C) Dead volume                        = All tanks foundation volume + Liquid volume of tanks (other than the largest tank) upto the Ht. of the enclosure + Dead volume of Fire wall1) All Tank foundation volume:   Volume of a tank foundation = π/4 D2 X h X nLet ,D1 : Fdn Dia of 300 tank = 37.5 M; D2 : Fdn Dia of 250 tank = 26.5 M; D3 : Fdn Dia of 210 tank = 22.5 Mn1 : Number of 300 tank fdns = 2 nos; n2 : Number of 250 tank fdns = 4 nos; n3 : Number of 210 tank fdns = 6 nos;Volume of all tank foundations = π/4 D1

2 X h X n1 + π/4 D22 X h X n2 + π/4 D3

2 X h X n3

                                                                                           =  π/4 X 37.52 X 0.9 X 2+ π/4 X 26.52 X 0.9 X 4  + π/4 X 22.52 X 0.9 X 6= 1988.04 + 1985.56 +2147.08= 6120.68 M3        …………………………………………………..(1)2) Liquid volume of tanks (other than the Largest Tank) above Fdn upto Dyke Ht:Liquid volume of tank above Fdn upto Dyke Ht. = π/4 d2 X (H-h) X n= π/4 d2 X (0.3) X nWhere, d : Dia of Tankn : Number of tankTotal Volume of all tanks (other than the Largest Tank) above Fdn upto Dyke Ht:= π/4 d1

2 X (0.3) X n1 +π/4 d22 X (0.3) X n2+π/4 d3

2 X (0.3) X n3

= π/4 X (36)2 X (0.3) X 1 +π/4 X (25)2 X (0.3) X 4+π/4 X (21)2 X (0.3) X 6= 305.36 + 589.05 + 623.45= 1517.86 M3          …………………………………………………..(2)3) Dead Volume of Fire wall = 0.2 X 0.6 X (56 + 199+ 77.5 + 77.5 + 77.5 + 77.5 + 77.5) = 77.1 M3

= 100 M3 (Min Dead Volume of Sleepers & Crossovers) ……………..(3)C) Dead volume                 = (1) + (2) + (3)= 6120.68 + 1517.86 + 100= 7738.54 M3

B + C       = 17304 + 7738.54= 25042.54 M3

A             = 25899 M3

A             >       B + CDyke height (1.2 M) assumed is OK.As per OISD, 200 MM free board is to be added to Dyke heightDyke Wall Height = 1.2 + 0.2= 1.4 M