Safety of Mu­ni­tions on the High Sea

De­spite all the pre­cau­tions dur­ing de­sign and op­er­a­tion of mag­a­zines, ac­ci­dents do take place with am­mu­ni­tion, which lead to ter­ri­ble out­comes on war­ships and loss of pre­cious lives. a need was there­fore felt to make ex­plo­sives in­her­ently less sen­si­tive s

SP's NavalForces - - ARMAMENTS - REAR AD­MI­RAL (RETD) DR S. KUL­SHRESTHA En­vi­ron­men­tal con­trol of mag­a­zines: Sprin­klers and alarms: In­spec­tions: Move­ment of am­mu­ni­tion:

SaFeTy OF aM­MU­NI­TION aND ex­plo­sives on­board is of para­mount im­por­tance for the sur­vival of the war­ship. There are two as­pects which merit at­ten­tion in this re­gard; one per­tains to the safety and preven­tion of fire dur­ing stor­age of th­ese po­ten­tially haz­ardous items and the other to mak­ing the ex­plo­sive de­vices safe for stor­age by im­prov­ing their com­po­si­tions.

Stowage of Am­mu­ni­tion and Ex­plo­sives on Board

a war­ship takes on­board only that am­mu­ni­tion which has been cer­ti­fied fit for use by the ar­ma­ment in­spec­tion agency. Stowage of am­mu­ni­tion and ex­plo­sives on­board is a com­plex de­sign ex­er­cise due to space con­straints, po­si­tion­ing of ad­ja­cent equip­ment com­part­ments de­pend­ing upon hazards posed, ease of weapon han­dling, po­si­tion­ing of am­mu­ni­tion de­liv­ery mech­a­nisms, min­imis­ing dam­age, ease of fire­fight­ing and so on. The prob­lem is fur­ther com­pli­cated as the stowage has to be se­cure against roll, pitch and yaw mo­tions of the ship, ex­tremely high hu­mid­ity lev­els and var­i­ous in­ten­si­ties of storms. There are ex­plicit de­sign guide­lines, which are re­fined pe­ri­od­i­cally for safety en­hance­ment. as for the am­mu­ni­tion, its re­main­ing op­er­a­tional life is cal­cu­lated de­pend­ing upon the lev­els of en­vi­ron­men­tal stresses ex­pe­ri­enced by it dur­ing its stor­age on­board as well as the preva­lent shock and vi­bra­tion lev­els of a par­tic­u­lar type of ship.

There are dif­fer­ent types of stowage spa­ces for dif­fer­ent types of am­mu­ni­tion and ex­plo­sives and they are stored in sep­a­rate lock­ers or mag­a­zines. The lock­ers and mag­a­zines are clearly marked in­di­cat­ing the type of ex­plo­sives, its fire safety hazard and the per­mis­si­ble quan­tity in that space. The warn­ings on stowage spa­ces are prom­i­nent and visu­ally in­dica­tive leav­ing no doubts in the minds of per­son­nel en­ter­ing the area.

There are var­i­ous types of mag­a­zines namely pri­mary, mis­sile, ready to use mag­a­zines and lock­ers. Pri­mary mag­a­zines are gen­er­ally lo­cated be­low the wa­ter­line and are equipped with tem­per­a­ture con­trol, heat in­su­la­tors and ad­e­quate means of ven­ti­la­tion. Mis­siles mag­a­zines are a spe­cial cat­e­gory since mis­siles are largely in­te­grated in na­ture i.e. the safety and arm­ing mech­a­nism is pre-as­sem­bled to the war­head, which in turn is con­nected to the elec­tron­ics and the rocket pro­pel­lant, thus rais­ing its hazard level. Fur­ther, they are housed in spe­cial cas­ings, boxes or can­is­ters and stored sep­a­rately. The han­dling equip­ment to bring them to the launcher could be op­er­ated by a com­bi­na­tion of elec­tric-pneu­matic and/or hy­draulic sys­tems. ex­treme care is re­quired dur­ing han­dling as the rocket pro­pel­lant may ig­nite in case the mis­sile falls and thereby launches the mis­sile in a con­fined space caus­ing havoc. ready to use mag­a­zines are lo­cated near the weapon for which they are in­tended. Those are also well ven­ti­lated, in­su­lated from heat and fit­ted with sprin­klers. am­mu­ni­tion lock­ers are used to store spe­cial types of ex­plo­sives and am­mu­ni­tion such as det­o­na­tors and py­rotech­nics. The lock­ers are se­cured to the deck of the ship and it is en­sured that am­mu­ni­tion in­side does not move or rat­tle about dur­ing rou­tine mo­tion of the ship at sea.

Sin­gle pur­pose mag­a­zines are those which store a sin­gle type of ex­plo­sive store for e.g. rocket mo­tor mag­a­zine, small arms mag­a­zine, fixed am­mu­ni­tion mag­a­zine, mis­sile mag­a­zine, fuse mag­a­zine, det­o­na­tor locker, py­rotech­nic locker and so on. Mixed ex­plo­sive stor­ages are also per­mis­si­ble in cer­tain com­bi­na­tions of ex­plo­sive stores de­pend­ing upon the sever­ity of ex­plo­sive sen­si­tiv­ity. It is en­sured how­ever that the am­mu­ni­tion stored on­board is as per reg­u­la­tions and within per­mis­si­ble lim­its. Mag­a­zines are fit­ted with safety and en­vi­ron­ment con­trol fea­tures, so that the am­mu­ni­tion and ex­plo­sives re­main pro­tected from ex­ces­sive hu­mid­ity and tem­per­a­ture. Ven­ti­la­tion and ex­haust sys­tems are in­stalled in the mag­a­zines and they are reg­u­larly vented to evac­u­ate ac­cu­mu­lated toxic gases if any. Mis­sile mag­a­zines are vented to the at­mos­phere for the sim­ple rea­son that in case a mis­sile rocket mo­tor func­tions, its ex­haust is im­me­di­ately vented to the at­mos­phere be­fore it can spread to other ar­eas.

Largely, all types of mag­a­zines have sprin­kler sys­tems fit­ted in such a way that wa­ter is sprayed on to the am­mu­ni­tion and ex­plo­sives and the en­tire mag­a­zine is flooded in case of smoke/fire de­tec­tion or rapid rise in tem­per­a­ture. Th­ese can be op­er­ated au­to­mat­i­cally by re­mote con­trol or man­u­ally. am­mu­ni­tion, which func­tions by ingress of wa­ter, is not stored in such mag­a­zines. The alarm sys­tem com­prises of alarms that op­er­ate on de­tec­tion of high tem­per­a­ture, ac­ti­va­tion of sprin­klers and func­tion­ing of flood­ing sys­tems.

Mag­a­zine in­spec­tions are car­ried out by qual­i­fied sailors and recorded in in­spec­tion logs. Daily in­spec­tion in­volves en­sur­ing that am­mu­ni­tion is prop­erly se­cured, the mag­a­zine is clean, there is no pres­ence of fumes or odour and that there is noth­ing out of the or­di­nary in and around the mag­a­zine. Spe­cial at­ten­tion is paid to the fact that there should be no hin­drances in en­try and exit to the mag­a­zine, ab­nor­mal­ity in rise of tem­per­a­ture and hu­mid­ity charts, un­nat­u­ral ac­cu­mu­la­tion of ma­te­rial in and around the area, etc. In ad­di­tion, the mag­a­zine and sur­round­ing area is in­spected for leak­ages or break­ages in sprin­kler sys­tems, func­tion­ing of alarm sys­tems and ab­nor­mal heat­ing in ad­ja­cent com­part­ments. each mag­a­zine is mon­i­tored for tem­per­a­ture and hu­mid­ity and records of max­i­mum and min­i­mum val­ues are en­tered in the mag­a­zineÕs log card in­side the mag­a­zine. The mag­a­zines are in­spected prior to lock­ing and re­main locked when no ac­tiv­ity is be­ing car­ried out and only au­tho­rised per­son­nel can ac­cess them.

Shift­ing of am­mu­ni­tion for rou­tine fir­ing ex­er­cises, re­arrange­ment or dur­ing am­mu­ni­tion­ing/ deam­mu­ni­tion­ing are in­her­ently dan­ger­ous ac­tiv­i­ties where the slight­est mis­take can lead to cat­a­strophic sit­u­a­tions. There­fore, ut­most care is ex­er­cised dur­ing such work. ex­plicit or­ders are avail­able for each ac­tiv­ity and it is en­sured that the or­ders are com­plied with at all times. am­mu­ni­tion­ing and deam­mu­ni­tion­ing is car­ried out at des­ig­nated jet­ties or ex­plo­sive an­chor­ages so that in case of any ac­ci­dent, the dam­age is lim­ited to that ship only. Trans­fer of am­mu­ni­tion at sea is car­ried out only in ex­cep­tional cir­cum­stances as it is a very dan­ger­ous ac­tiv­ity. De­tailed or­ders are pre­pared by both ships and prepa­ra­tions checked and rechecked prior to car­ry­ing out this op­er­a­tion. The ships re­main in high­est de­gree of nu­clear, chem­i­cal and bi­o­log­i­cal dam­age con­trol readi­ness dur­ing the process.

In­sen­si­tive Mu­ni­tions

De­spite all the pre­cau­tions dur­ing de­sign and op­er­a­tion of mag­a­zines, ac­ci­dents do take place with am­mu­ni­tion, which lead to ter­ri­ble out­comes on war­ships and loss of pre­cious lives. The men on­board a war­ship work and sleep vir­tu­ally next to the mag­a­zines, ac­ci­den­tal fires in other ar­eas may also lead to ex­plo­sions or large fires in mag­a­zines due to cook off or other causes. a need was there­fore felt to make ex­plo­sives in­her­ently less sen­si­tive so that they re­main pas­sive to ex­ter­nal stim­uli like heat, shock, bul­let or frag­ment im­pact and sym­pa­thetic det­o­na­tion in case nearby mu­ni­tions func­tion. The ge­n­e­sis of the thrust in in­sen­si­tive am­mu­ni­tion de­vel­op­ment lay in two ma­jor ac­ci­dents in the US, namely the 1966 Palo­mares b-52 Crash and the 1968 Thule air base b-52 Crash in which the high ex­plo­sive de­vices used in the nu­clear bombs had det­o­nated on im­pact. The US Navy too has wit­nessed many ac­ci­dents in the 1960s. In 1966, there was a fire on­board USS Oriskany due to mis­han­dling of an air­craft flare, which led to det­o­na­tion of 2.75 rocket war­heads and re­sulted in the death of 44 sailors. In 1967, a five-inch Zuni rocket loaded on the pod of an F-4 air­craft on­board USS For­re­stal was ac­ci­den­tally fired, which in turn led to fires and func­tion­ing of sev­eral bombs, rock­ets and mis­siles. The dis­as­ter re­sulted in deaths of 134 per­son­nel. In 1969, on­board USS en­ter­prise, the ex­haust from an air­craft en­gine starter unit caused det­o­na­tion of five-inch Zuni rock­ets, whose war­heads were filled with com­po­si­tion b ex­plo­sives. This re­sulted in 18 war­head ex­plo­sions and 28 deaths. In De­cem­ber, the same year, am­mu­ni­tion ship SS badger en­coun­tered rough seas dur­ing a storm due to which the bombs broke loose from the pal­lets and led to ex­plo­sions as they were tossed around the deck. The ship had to be aban­doned and 26 lives were lost. In ad­di­tion, the US Navy ex­pe­ri­enced 16 pre­ma­ture ex­plo­sions of shells of high cal­i­bre guns dur­ing the pe­riod De­cem­ber 1968 and Jan­uary 1973. The shells were ei­ther filled with Com­po­si­tion A-3, Com­po­si­tion b or ex­plo­sive D. The in­ci­dent on­board USS New­port on Oc­to­ber 1, 1972, de­serves men­tion, in which the pro­jec­tile of eight-inch Ôbag gunÕdet­o­nated in ram po­si­tion in the gun cham­ber. In the ex­plo­sion and en­su­ing fire, 20 sailors died. Com­po­si­tions of the type men­tioned above are prone to ig­ni­tion when sub­jected to adi­a­batic heat­ing dur­ing op­er­a­tion/ac­cel­er­a­tion of pro­jec­tile in the gun bar­rel. The above in­ci­dents and sim­i­lar ones in the army de­pots pro­vided im­pe­tus to re­search on in­sen­si­tive mu­ni­tions.

Con­cep­tu­ally in­sen­si­tive mu­ni­tions should not ex­plode but only burn when sub­jected to slow and fast heat­ing, hits by bul­lets, shrap­nel or shaped charges. re­search is be­ing pro­gressed adopt­ing ap­proaches, like ex­ter­nally pro­tect­ing the ex­plo­sive de­vice dur­ing trans­porta­tion by in­cor­po­rat­ing ther­mal in­su­la­tion and vent­ing, and by im­prov­ing ex­plo­sive com­po­si­tions to pro­vide high sta­bil­ity. In­sen­si­tive mu­ni­tions con­tain shock and fire re­sis­tant ‘in­sen­si­tive high ex­plo­siveÕ­like plas­tic/poly­mer bonded ex­plo­sives or tri­aminotrini­troben­zene (TaTb). TaTbÕs shock and ther­mal sta­bil­i­ties are higher than that of any other com­pa­ra­ble ma­te­rial. Fur­ther it is rea­son­ably pow­er­ful

PHO­TO­GRAPH: US Navy

Rows of ord­nance dur­ing am­mu­ni­tion on load at Naval Weapons Sta­tion, Earle, New Jersey

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