Fixed systems and methods for extinguishing industrial tank fires, with and without fixed roof, including aerated foam projecting nozzles and center directed nozzles

Abstract

Fixed systems and method for extinguishing large scale industrial tank fires, with and without fixed roofs, and featuring aerated foam projecting nozzles and including fixed center directed nozzles.

Claims

1. An aerated foam fire fighting apparatus structured for attachment to a tank with a fixed roof, comprising: a first ambient air aeration chamber located upstream of, and in fluid communication with, a fire fighting nozzle, the first ambient air aeration chamber structured to produce aerated foam; a tapered portion located downstream of, and in fluid communication with, the first ambient air aeration chamber, the tapered portion having a first end and a second end, the first end of the tapered portion being larger than the second end of the tapered portion, the second end being connected to a tip portion of the fire fighting nozzle; at least one stream shaper located in the tip portion of the fire fighting nozzle, the at least one stream shaper having fins with a longitudinal dimension greater than a radial dimension, the fins terminating substantially flush with a discharge orifice; and at least two discharge ports located in a fluid conduit between the first ambient air aeration chamber and tip portion of the fire fighting nozzle, each discharge port having a deflector portion located in the conduit proximate each discharge port.

2. The apparatus of claim 1, comprising: the fire fighting nozzle structured with the first ambient air aeration chamber to forcefully project aerated foam in a substantially focused stream; and a stream straightener located in the fluid conduit upstream of, and proximate the discharge ports.

3. The apparatus of claim 2, wherein the first ambient air aeration chamber is structured to produce aerated foam with an expansion ratio of between 2-to-1 and 8-to-1.

4. The apparatus of claim 3 comprising: a third discharge port located in the fluid conduit between the first ambient air aeration chamber and the nozzle tip, the third discharge port structured to discharge up to 150 gallons per minute (gpm) in a direction roughly perpendicular to a discharge axis defined by the two discharge ports.

5. The apparatus of claim 2, wherein the first ambient air aeration chamber is structured to produce aerated foam with an expansion ratio of between 3-to-1 and 5-to-1.

6. The apparatus of claim 2, wherein the at least two discharge ports are structured to discharge aerated foam in opposing directions.

7. The apparatus of claim 2 comprising: an at least 4 inch riser structured for communicating aerated foam outside of the tank wall and in fluid communication with the first ambient air aeration chamber.

8. The apparatus of claim 7 comprising: a vapor membrane located between the riser and the first ambient air aeration chamber.

9. The apparatus of claim 1, wherein the first ambient air aeration chamber is structured to produce aerated foam with an expansion ratio of between 2-to-1 and 8-to-1.

10. The apparatus of claim 9 comprising: a third discharge port located in the fluid conduit between the first ambient air aeration chamber and the nozzle tip, the third discharge port structured to discharge up to 150 gallons per minute (gpm) in a direction roughly perpendicular to a discharge axis defined by the two discharge ports.

11. The apparatus of claim 9 comprising: the nozzle structured to forcefully project between 200 gallons per minute (gpm) and 1000 gpm, at 100 pound per square inch (psi), of aerated foam, in a substantially focused stream; and the at least two discharge ports including: a pair of opposing discharge ports upstream of the discharge orifice of the nozzle tip, with interior deflector surfaces structured to deflect a portion of aerated foam passing through the conduit toward the discharge ports.

12. The apparatus of claim 1, wherein the first ambient air aeration chamber is structured to produce aerated foam with an expansion ratio of between 3-to-1 and 5-to-1.

13. The apparatus of claim 12 comprising: the nozzle structured to forcefully project between 200 gallons per minute (gpm) and 1000 gpm, at 100 pound per square inch (psi), of aerated foam, in a substantially focused stream; and the at least two discharge ports including: a pair of substantially opposing discharge ports upstream of the discharge orifice of the nozzle tip, with interior deflector surfaces structured to deflect a portion of aerated foam passing through the conduit toward the discharge ports.

14. The apparatus of claim 1, wherein the at least two discharge ports are structured to discharge aerated foam in roughly opposing directions.

15. The apparatus of claim 1 comprising: an at least 4 inch riser structured for communicating aerated foam outside of a tank wall and in fluid communication with the first ambient air aeration chamber.

16. The apparatus of claim 15 comprising: a vapor membrane located between the riser and the first ambient air aeration chamber.

17. An aerated foam fire fighting apparatus structured for attachment to an industrial tank, comprising: an ambient air aeration chamber located upstream of, and in fluid communication with a fire fighting nozzle, the ambient air aeration chamber structured to produce aerated foam; a tapered portion located downstream of, and in fluid communication with, the ambient air aeration chamber, the tapered portion having a first end and a second end, the first end of the tapered portion being larger than the second end of the tapered portion, the second end being connected to a tip portion of the fire fighting end nozzle; at least one stream shaper located in the tip portion of the fire fighting nozzle, the tip portion terminating the fire fighting nozzle at an outermost end, the at least one stream shaper having fins, the fins terminating proximate the outermost end; and at least two discharge ports located in a fluid conduit downstream of, and in communication with, the ambient air aeration chamber, the at least two discharge ports structured to discharge aerated foam in a roughly horizontal direction and in a roughly opposing directions around an interior top tank wall surface of the industrial tank, each discharge port having a deflector portion located in the fluid conduit proximate each discharge port.

18. The apparatus of claim 17, comprising: the fire fighting nozzle structured with the ambient air aeration chamber to forcefully project aerated foam in a substantially focused stream; and a stream straightener located in the fluid conduit upstream of and proximate the discharge ports.

19. A method for extinguishing fire in a fixed roof large industrial tank, comprising: providing the apparatus of claim 1; forcefully projecting through an opening in a top portion of a large industrial tank wall aerated foam, having an expansion ratio of between 2-to-1 to 8-to-1, radially toward the center of the tank in a substantially focused stream through a conduit having an aerated foam, forcefully projecting nozzle at its distal end; and projecting aerated foam through two discharge ports located on the side of the conduit upstream of the nozzle at the conduit distal end, in roughly opposing directions, along interior side wall portions of the tank.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) A better understanding of the present invention can be obtained when the following detailed description of the preferred embodiments are considered in conjunction with the following drawings, in which:

(2) FIG. 1 illustrates an embodiment of a fixed system having two aerated foam projecting nozzles discharging foam in opposing directions, roughly horizontally, along a top portion of a tank wall and having a third center projecting nozzle connected thereto, with the projecting nozzle and the pair of aerated foam projecting nozzles each having their own ambient air aeration chamber proximately upstream.

(3) FIG. 2 is a cut-away view of the embodiment of FIG. 1.

(4) FIG. 3A indicates the embodiment of FIG. 1 including the attachment of the three nozzles to a single riser located proximate the outside tank wall of a tank.

(5) FIGS. 3B and 3C illustrate alternate embodiments for a fixed system with the aerated foam projecting nozzles projecting horizontally along the tank wall and including the center pointing nozzle. FIGS. 3B and 3C illustrate that the center pointing nozzle can be attached to its own riser, independently of the riser for the pair of aerated foam projecting nozzles projecting horizontally along the inner tank wall.

(6) FIGS. 4A-4D are drawings illustrating the embodiment of FIG. 3A in detail.

(7) FIGS. 5A-5F are drawings of the “wand head” of FIG. 3A in detail, the wand head including nozzle wand head with a center pointing nozzle and a pair of left/right foam projecting inner wall nozzles.

(8) FIG. 6 is relevant because of FIG. 3B. FIG. 3B presents an embodiment where the riser for the center pointing nozzle is separate from the riser for the two left/right directed nozzles. Hence, the center pointing nozzle can actually be located independently and separately from the left/right directed nozzles, using its own riser. Preferably a riser includes a riser top portion, a riser extension pipe and a riser inlet pipe, as illustrated in FIG. 6.

(9) FIG. 7 illustrates a foot rest kit to help support an independent riser, also attached by brackets to a tank wall.

(10) FIGS. 8A-8G illustrates with drawings the embodiment of FIG. 6 for establishing a fixed riser proximate a tank wall, useful for attaching a center pointing nozzle.

(11) FIG. 9 is a table correlating preferred flow rates for the left right pointing nozzle and the center pointing nozzle, referred to as “upper,” to tank diameters.

(12) FIG. 10 illustrates planning for an arrangement of nozzles of the Ambush system, including the three fixed nozzle type, given a tank size.

(13) FIG. 11 illustrates a proposed placement of three nozzle fixed wands to cover a fire in a 300 foot diameter tank.

(14) FIG. 12 illustrates staging three nozzle wands around a 405 foot diameter tank, including gpms.

(15) FIG. 13 illustrates staging three nozzle fixed wands around a 277 foot diameter tank, including flow per device, effective ranges and footprint size.

(16) FIG. 14 illustrates a fixed nozzle wand for fitting into an existing opening of a tank with a fixed roof.

(17) FIG. 15 is a partial cutaway of the nozzle of FIG. 14.

(18) FIG. 16 is a side view of the nozzle of FIG. 14, showing the fixed nozzle wand installed through a tank wall.

(19) FIG. 17 shows the embodiment of FIG. 14 together with a riser to form a full wand.

(20) FIG. 18 shows the embodiment of FIG. 14 together with the riser to form a full wand attached to a tank wall.

(21) FIGS. 19A-19C show the embodiment of FIG. 14 together with the riser, attached to a tank wall and with an indication of further sourcing of water and foam concentrate.

(22) FIG. 20 illustrates the number of fixed nozzle systems with dual side ports required for full surface protection of a fixed roof tank, by tank diameter.

(23) The drawings are primarily illustrative. It would be understood that structure may have been simplified and details omitted in order to convey certain aspects of the invention. Scale may be sacrificed to clarity.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(24) FIG. 1 illustrates a preferred embodiment of a wand head WH for a fixed fire fighting system for a large industrial tank. The wand head WH is indicated as installed proximate to the tank wall portion TW, in fact utilizing support panel SP for extra support. The nozzles AFPN and CPN of the wand head are located with respect of the tank to discharge just over the tank wall. The embodiment of FIG. 1 includes center pointing nozzle CPN and a pair of aerating foam projecting nozzles AFPN. The aerating foam projecting nozzles discharge substantially horizontally and in roughly opposing directions along an upper interior edge of the tank wall TW. The aerated foam projecting nozzles are shown with a tip portion TP and a stream shaper SS located in the tip having fins FN that terminate substantially flush with the discharge opening DO of the tip. Riser RS passes through the wind girder WG and furnishes water and foam concentrate to the embodiment of three nozzles. Each nozzle is shown with its own ambient air aeration chamber AAAC locating proximate to the nozzle and just upstream of the nozzle.

(25) FIG. 2 is a partial cutaway of the embodiment of FIG. 1. The ambient air aeration chambers can be shown to be of a tubular jets type having a tubular jets TJ within ports for drawing in air in a fashion known in the art. The embodiment of FIG. 1 is further illustrated in FIG. 3 showing a full riser RS coming from proximate the ground and rising to proximate the top of the tank wall TW. The riser passes through the wind girder WG.

(26) FIGS. 3B-1 and 3B-2 illustrates an alternate embodiment of the instant fixed system invention illustrated in FIG. 3A. In FIG. 3B the center pointing nozzle CPN, although nominally attached to the conduit of the pair of aerated foam projecting nozzles AFPN, has not only its separate ambient air aeration chamber AAAC2 (from AAAC1) but its separate riser RS2 (from RS1.) Given the configuration of FIG. 3B, it is clear that the center pointing nozzle can actually be physically separated from the wand of the pair of aerated foam projecting nozzles. Each can have their own aeration chamber and each can have their own riser.

(27) It becomes further apparent that riser RS2 not only need not be located next to riser one RS1, but the nozzle attached to the second riser could actually be any effective fire fighting nozzle for discharging foam to cover center portions of the tank. It may, but need not have, a proximate ambient air aeration chamber AAAC2. It could be a nozzle of the sort that relies upon aeration by virtue of substantial flight of the air.

(28) FIGS. 4A-4D offer a drawing sheet showing particulars of the wand head of the embodiment of FIG. 1. FIG. 4C illustrates by dashed lines the roughly horizontal direction and roughly opposing directions of the pair of aerated foam projecting nozzles.

(29) FIGS. 5A-5F show further details of the wand head of the embodiment of FIG. 1 including drawing cutaways showing the tubular jet TJ in the aeration chamber AAAC, the stream shaper SS and the fins FN therein.

(30) FIG. 6 illustrates three sections of a potentially free standing riser that might be used to separately locate a center pointing nozzle of any appropriate size and style. These riser portions, including a riser top portion RTP, a riser extension pipe REP and riser inlet pipe RIP, are intended to be joined together and provide a free standing riser for attaching (most likely) a center pointing nozzle. The center pointing nozzle could be fixedly attached, and as discussed previously, need not necessarily include an ambient air aeration chamber. FIG. 7 illustrates a riser foot rest RFR and a bracket BR both useful for securing a riser RS proximate a tank wall. FIGS. 8A-8G illustrates in further detail a riser RS and method and apparatus for securing a riser proximate and adjacent a tank wall, including brackets BR and riser footrest RFR.

(31) FIG. 9 illustrates figuring a three nozzle fixed wand configuration into a system for tank sizes from 150 foot diameter to a 500 foot diameter. A proposed optimum flow both for the left and right pointing aerating projecting nozzles and for upper and center pointing nozzles is indicated.

(32) FIG. 10 illustrates calculations that affect the type and number of fixed three nozzle wands required for a tank surface. FIG. 10 indicates that in the annular area, supplied with foam by the aerated foam protecting nozzles, an application rate of 0.10 gpm per square foot is recommended. For the open surface area of the middle of the tank, an application rate of at least 0.16 gpm per square foot is recommended.

(33) FIG. 11 represents calculations for a fixed system of the instant invention for a 300 foot diameter tank. The tank is shown configured with seven fixed systems discharging left, right, and toward the center. Application rate densities are indicated. Total gpm for all devices is indicated as well as the gpm per three nozzle wand. A gpm against the wall indicated in FIG. 11 comes from a port in the conduit that discharges up to 150 gpm down under any wand as a safeguard.

(34) FIG. 12 illustrates calculations for a 405 foot diameter tank where ten three nozzle wands are proposed each wand providing 1,300 gpm total against the inner wall and 600 gpm toward the center. FIG. 12 indicates a design of a fixed three nozzle aerated foam wand system for extinguishing a full surface liquid tank fire in a 405 foot diameter tank. Ten dispersing units are prescribed. Each unit is assumed to have three nozzles, one dispersing to the left, one to the right and one toward the center. All three nozzles disperse 600 gpm. In addition 100 gpm is dispersed downward against the wall. (This fourth direction may not be needed, or may be optional). The landing footprints for the ten nozzles discharging toward the center of the tank are predicted to project a footprint to land approximately 150 feet away from the tank wall. The foam should easily run an additional 55 feet or so toward the center, as well as return back toward the wall 30 feet or more to meet foam from the nozzles discharging left and right expanding toward the center of the tank from the walls. The drawing FIG. 12 in addition indicates a fallout region from the discharge path of the nozzles discharging toward the center of the tank. The fallout region supplies foam into mid-radial annular areas of the tank. The drawing indicates a capacity to blanket a 400 foot diameter tank with foam using ten fixed units.

(35) An attached spreadsheet shows how the three nozzle fixed system can plan and provide a fixed system full surface fire protection for tank sizes from 100 foot diameter to 500 foot diameter.

(36) TABLE-US-00003 Total Flow Flow Distance Required to Required Actual Flow Desired Actual Surface Between Achieve Desired From Each Actual From each Tank Number Application Application Area of Tank Devices Application Device Total Device Size of Devices Density Density Tank Circumference (<180″) Density (<Actual) Flow (GPM) 100 2 0.12 0.17 7850 314 157 942 471 1300 650 110 2 0.12 0.14 9499 345 173 1140 570 1300 650 120 3 0.12 0.17 11304 377 126 1356 452 1950 650 130 3 0.12 0.15 13267 408 136 1592 531 1950 650 140 3 0.12 0.13 15386 440 147 1846 615 1950 650 150 4 0.12 0.15 17663 471 118 2120 530 2600 650 160 4 0.12 0.13 20096 502 126 2412 603 2600 650 170 3 0.12 0.15 22687 534 178 2722 907 3300 1100 180 4 0.12 0.17 25434 565 141 3052 763 4400 1100 190 4 0.12 0.16 28339 597 149 3401 850 4400 1100 200 4 0.12 0.14 31400 628 157 3768 942 4400 1100 210 4 0.12 0.13 34619 659 165 4154 1039 4400 1100 220 5 0.12 0.14 37994 691 138 4559 912 5500 1100 230 5 0.12 0.13 41527 772 144 4983 997 5500 1100 240 5 0.13 0.17 45216 754 151 5878 1176 7500 1500 250 5 0.13 0.15 49063 785 157 6378 1276 7500 1500 260 5 0.13 0.14 53066 816 163 6899 1380 7500 1500 270 5 0.13 0.13 57227 848 170 7439 1488 7500 1500 280 6 0.13 0.15 61544 879 147 8001 1333 9000 1500 290 6 0.13 0.14 66019 911 152 8582 1430 9000 1500 300 7 0.13 0.15 70650 942 135 9185 1312 10500 1500 310 8 0.13 0.16 75439 973 122 9807 1226 12000 1500 920 6 0.14 0.14 88384 1005 167 11254 1876 11400 1900 330 7 0.14 0.16 85487 1036 148 11968 1710 13300 1900 340 7 0.14 0.15 90746 1068 153 12704 1815 13300 1900 350 8 0.14 0.16 96163 1099 137 13483 1683 15200 1900 360 9 0.15 0.17 101736 1130 126 15260 1696 17100 1900 370 8 0.15 0.16 107467 1162 145 16120 2015 16800 2100 380 9 0.15 0.17 113354 1193 133 17003 1889 18900 2100 390 9 0.15 0.16 119399 1225 136 17910 1990 18900 2100 400 10 0.15 0.17 125600 1256 126 18840 1884 21000 2100 410 10 0.15 0.16 131959 1287 129 19794 1979 21000 2100 420 9 0.16 0.18 138474 1319 147 22156 2462 24300 2700 430 10 0.16 0.19 145147 1350 135 23223 2322 27000 2700 440 10 0.16 0.18 151976 1382 138 24316 2432 27000 2700 450 11 0.16 0.19 158963 1413 128 25434 2312 29700 2700 460 12 0.16 0.20 166106 1444 120 26577 2215 32400 2700 470 13 0.16 0.20 173407 1476 114 27745 2134 35100 2700 480 13 0.16 0.19 180864 1507 116 28988 2226 35100 2700 490 14 0.16 0.20 188479 1539 110 30157 2154 37800 2700 500 15 0.16 0.21 196250 1570 105 31400 2093 40500 2700

(37) TABLE-US-00004 AMBUSH SYSTEM Flow Breakdown (GPM) Open Surface Annular Area 3″-5″ Left Right Upper Wall Surface Surface Application Total Upper Surface Total Application Foam 300 300 0 50 0 0 0.00 0 7850 1300 0.17 3.7 300 300 0 50 0 0 0.00 0 9499 1300 0.14 4.5 300 300 0 50 0 0 0.00 0 11304 1950 0.17 3.6 300 300 0 50 0 0 0.00 0 13267 1950 0.15 4.2 300 300 0 50 0 0 0.00 0 15386 1950 0.13 4.9 300 300 0 50 0 0 0.00 0 17663 2600 0.15 4.2 300 300 0 50 0 0 0.00 0 20096 2600 0.13 4.8 400 400 200 100 10 79 7.64 600 22608 2700 0.12 4.3 400 400 200 100 20 314 2.55 800 25120 3600 0.14 3.6 400 400 200 100 30 707 1.13 800 27632 3600 0.13 4.0 400 400 200 100 40 1256 0.64 800 30144 3600 0.12 4.4 400 400 200 100 50 1963 0.41 800 32656 3600 0.11 4.9 400 400 200 100 60 2826 0.35 1000 35168 4500 0.13 4.3 400 400 200 100 70 3847 0.26 1000 37680 4500 0.12 4.7 500 500 400 100 80 5024 0.40 2000 40192 5500 0.14 3.7 500 500 400 100 90 6359 0.31 2000 42704 5500 0.13 4.1 500 500 400 100 100 7850 0.25 2000 45216 5500 0.12 4.4 500 500 400 100 110 9499 0.21 2000 47728 5500 0.12 4.7 500 500 400 100 120 11304 0.21 2400 50240 6600 0.13 4.2 500 500 400 100 130 13267 0.18 2400 52752 6600 0.13 4.5 500 500 400 100 140 15386 0.18 2800 55264 7700 0.14 4.2 500 500 400 100 150 17663 0.18 3200 57776 8800 0.15 3.9 600 600 600 100 160 20096 0.18 3600 60288 7800 0.13 4.4 600 600 600 100 170 22687 0.19 4200 62800 9100 0.14 4.0 600 600 600 100 180 25434 0.17 4200 65312 9100 0.14 4.2 600 600 600 100 190 28339 0.17 4800 67824 10400 0.15 3.9 600 600 600 100 200 31400 0.17 5400 70338 11700 0.17 3.7 600 600 800 100 210 34619 0.18 6400 72848 10400 0.14 4.0 600 600 800 100 220 37994 0.19 7200 75360 11700 0.16 3.7 600 600 800 100 230 41527 0.17 7200 77872 11700 0.15 3.9 600 600 800 100 240 45216 0.18 8000 80384 13000 0.16 3.7 600 600 800 100 250 49063 0.16 8000 82896 13000 0.16 3.9 800 800 1000 100 260 53066 0.17 9000 85408 15300 0.18 3.5 800 800 1000 100 270 57227 0.17 10000 87920 17000 0.19 3.3 800 800 1000 100 280 61544 0.16 10000 90432 17000 0.19 3.5 800 800 1000 100 290 66019 0.17 11000 92944 18700 0.20 3.3 800 800 1000 100 300 70650 0.17 12000 95456 20400 0.21 3.2 800 800 1000 100 310 75439 0.17 13000 97968 22100 0.23 3.1 800 800 1000 100 320 80384 0.16 13000 100460 22100 0.22 3.2 800 800 1000 100 330 85487 0.16 14000 102992 23800 0.23 3.1 800 800 1000 100 340 90746 0.17 15000 105504 25500 0.24 3.0

(38) TABLE-US-00005 Open Surface Equiv- Seal 1% 3% Area to Acceptable? alent Seal Area foam foam Meet 0.16 Actual Open Area Time flow flow Requirement Requirement Surface 615 1.3 715 2145 0 YES 0 678 1.4 715 2145 0 YES 0 741 1.0 1073 3218 0 YES 0 804 1.1 1073 3218 0 YES 0 867 1.2 1073 3218 0 YES 0 929 1.0 1430 4290 0 YES 0 992 1.0 1430 4290 0 YES 0 1055 0.9 2145 6435 3750 YES 69 1118 0.7 2860 8580 5000 YES 80 1181 0.7 2860 8580 5000 YES 80 1243 0.8 2860 8580 5000 YES 80 1306 0.8 2860 8580 5000 YES 80 1369 0.7 3575 10725 6250 YES 89 1432 0.7 3575 10725 6250 YES 89 1495 0.5 4875 14625 12500 YES 126 1557 0.6 4875 14625 12500 YES 126 1620 0.6 4875 14625 12500 YES 126 1683 0.6 4875 14625 12500 YES 126 1746 0.5 5850 17550 15000 YES 138 1809 0.5 5850 17550 15000 YES 138 1871 0.5 6825 20475 17500 YES 149 1934 0.4 7800 23400 20000 YES 160 1997 0.5 7410 22230 22500 YES 169 2060 0.4 8645 25935 26250 YES 183 2123 0.4 8645 25935 26250 YES 183 2185 0.4 9880 29640 30000 YES 195 2248 0.3 11115 33345 33750 YES 207 2311 0.4 10920 32760 40000 YES 226 2374 0.3 12285 36855 45000 YES 239 2437 0.3 12285 36855 45000 YES 239 2499 0.3 13650 40950 50000 YES 252 2562 0.3 13650 40950 50000 YES 252 2625 0.3 15795 47385 56250 YES 268 2688 0.3 17550 52650 62500 YES 282 2751 0.3 17550 52650 62500 YES 282 2813 0.2 19305 57915 68750 YES 296 2876 0.2 21060 63180 75000 YES 309 2939 0.2 22815 68445 81250 YES 322 3002 0.2 22815 68445 81250 YES 322 3065 0.2 24570 73710 87500 YES 334 3127 0.2 26325 78975 93750 YES 346

(39) FIG. 13 illustrates configuring 6 three nozzle fixed system wands to cover a 277 foot diameter tank. Each device would flow 1500 gpm giving a total system flow of 9000 gpm.

(40) FIG. 14 illustrates a riser RS and nozzle system appropriate for retro-fitting a tank with a fixed roof The nozzle is designed such that it can be inserted into an opening near the top of the side of the tank wall. A center pointing nozzle CPN is provided with a tip TP. A pair of ports P are provided on each side of the nozzle, each port having a deflector DF which deflects foam from the conduit out the ports. An ambient air aeration chamber AAAC is provided on top of a riser RS.

(41) FIG. 15 is a partial cross section of the embodiment of FIG. 14. It can be seen that a vapor seal VS is present between two flanges just above the jet nozzle TJ of the ambient air aeration chamber AAAC. The vapor seal is ruptured by a water stream when activating of the system. A better view of the deflectors DF proximate the ports P is given with the cutaway view, together with the location of the stream shaper SS and its fins FN in the tip TP of the center pointing nozzle CPN.

(42) FIG. 16 affords a side view of the embodiment of FIG. 15, showing the nozzle affixed through a flanged opening FO of the tank wall TW.

(43) FIG. 17 affords a full wand view of the embodiment of FIG. 14 with the riser RS attached to the wand head and the wand carrying the center pointing nozzle CPN.

(44) FIG. 18 illustrates again the nozzle embodiment of FIG. 14 installed through an opening FO of a tank wall TW of tank T. FIG. 18 also illustrates the riser RS bringing water foam concentrate from proximate the ground up to the nozzle located proximally a top portion of the tank wall.

(45) FIGS. 19A-19C illustrates a further installation of the nozzle embodiment of FIG. 14 in a tank wall TW under a fixed roof FR and including riser RS.

(46) FIG. 20 illustrates a computation of the required number of embodiments of a nozzle for a fixed roof in accordance with the embodiment of FIG. 14, as per tank diameter. Each nozzle as per the embodiment of FIG. 14 is designed to discharge a 1000 gpm total.

(47) The foregoing description of preferred embodiments of the invention is presented for purposes of illustration and description, and is not intended to be exhaustive or to limit the invention to the precise form or embodiment disclosed. The description was selected to best explain the principles of the invention and their practical application to enable others skilled in the art to best utilize the invention in various embodiments. Various modifications as are best suited to the particular use are contemplated. It is intended that the scope of the invention is not to be limited by the specification, but to be defined by the claims set forth below. Since the foregoing disclosure and description of the invention are illustrative and explanatory thereof, various changes in the size, shape, and materials, as well as in the details of the illustrated device may be made without departing from the spirit of the invention. The invention is claimed using terminology that depends upon a historic presumption that recitation of a single element covers one or more, and recitation of two elements covers two or more, and the like. Also, the drawings and illustration herein have not necessarily been produced to scale.