Safety Design Criteria for the BALL POWDER Process - American

8 Safety Design Criteria for the BALL P O W D E R Process

Downloaded by COLUMBIA UNIV on June 11, 2013 | http://pubs.acs.org Publication Date: April 6, 1979 | doi: 10.1021/bk-1979-0096.ch008

BILL CARROLL and JOHN J. NICHOLS Olin Corp., P.O. Box 222, St. Marks, FL 32355

The explosives industry offers a great challenge to the safety conscious designer. The general safety rules and regulations utilized by the explosives industry for basic design criteria are also used as the guidelines for design in the BALL POWDER process. However, many of the traditional process procedures of the explosives industry have not been retained or have been modified for the BALL POWDER process. The manufacture of BALL POWDER involves hazards, with added hazard due to the explosive nature of the material processed. Pumps, pipes, tanks, equipment, etc. are veritable bombs if handled improperly. As a result, there are certain safety design requirements unique to the process. The intention of this paper is to describe some of the more unusual safety design requirements. In order to better understand these requirements, a brief history of the type of process utilized in the manufacture of BALL POWDER is presented. Next those safety advantages internal to the process are summarized. Specific requirements in the areas of grain formation, nitroglycerine manufacture and transfer, and continuous drying are discussed. Finally, the basic fire protection system utilized is described. One of the most significant developments in the manufacture of any gunpowder in the last 60 years has been the development of the BALL POWDER process. BALL POWDER was originally produced in a batch method, but an alternate method was developed to overcome the problem of difference in particle size distribution required versus product distribution produced. The new process involved mechanical graining and batch hardening. While this overcame the size distribution problems, the capital cost was much greater than a regular batch plant. Development work was then directed to reducing the investment. The process developed consisted of continuous mechanical graining and continuous hardening. The continuous process exhibited superiority over conventional methods in both performance and process advantages. Increased safety was combined with rapid means of stabilization, 0-8412-0481-0/79/47-096-171$05.00/0 © 1979 American Chemical Society In Toxic Chemical and Explosives Facilities; Scott, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1979.


172

TOXIC C H E M I C A L A N D EXPLOSIVES FACILITIES

g r a i n formation, and solvent removal. The b a s i c raw m a t e r i a l i n the production of BALL POWDER i s n i t r o c e l l u l o s e . Two d i f f e r e n t forms of n i t r o c e l l u l o s e can be used, v i r g i n n i t r o c e l l u l o s e or FNH ( f l a s h l e s s , non-hygroscopic, single-base, extruded powder). The d i b u t y l p h t h a l a t e and d i n i t r o toluenes i n the FNH g r a i n must be extracted before being used i n the BALL POWDER process. The f i r s t stage i n the manufacture of BALL POWDER i s g r a i n formation. This operation includes four s e q u e n t i a l operations, c o n s i s t i n g of (1) lacquer preparation, (2) mechanical g r a i n i n g , (3) g r a i n shaping, and (4) g r a i n hardening. Lacquer p r e p a r a t i o n i s the operation which converts the base n i t r o c e l l u l o s e stock to a v i s c o u s dough-like lacquer. This i s accomplished by the a d d i t i o n of e t h y l acetate and v a r i o u s a d d i t i v e s to the n i t r o c e l l u l o s e i n a mixing v e s s e l where intimate mixing produces the lacquer. In the g r a i n i n g operation, the lacquer i s converted from a "doughy" mass to i n d i v i d u a l lacquer p a r t i c l e s by e x t r u s i o n through a mechanical p e l l e t i z e r . Shaping i s performed by t r a n s f e r r i n g a s l u r r y of lacquer p a r t i c l e s through a s e r i e s of jacketed tubes. The combination of l i q u o r ( t r a n s f e r f l u i d ) flow, l i q u o r composition, temperature, and s l u r r y v e l o c i t y i n the shapers causes the lacquer to round up i n t o b a l l s and give up i t s i n t e r n a l water. The lacquer grains a r e hardened without deformation of shape by removal of solvent i n a s e r i e s of evaporators. The l i q u o r i s removed from the powder, and the powder i s washed. The powder i s separated i n v a r i o u s s i z e s by a screening operation. Coating s t i l l s are used to impregnate the hardened powder with n i t r o g l y c e r i n e (increases energy p o t e n t i a l ) and coat i t with deterrent (modifies burning rate). The main f u n c t i o n of the dryers i s to dry the powder to a uniform moisture and v o l a t i l e content. Here the powder i s a l s o "glazed" with graphite (improves flow c h a r a c t e r i s t i c s ) and s a l t coated (to adjust b a l l i s t i c s performance). The powder i s then blended to improve b a l l i s t i c s u n i f o r m i t y and to meet b a l l i s t i c requirements of the s p e c i f i c products r e q u i r e d . Inherent

Process

Safety Advantages

One of the main advantages of the continuous process i s increased s a f e t y . There are c e r t a i n design requirements i n the continuous process which have r e s u l t e d i n an i n h e r e n t l y safe operation. (1) To reduce the hazard created by handling dry n i t r o c e l l u l o s e o r powder, a l l operations up to the f i n a l dry processing (75% of the handling) are c a r r i e d out under water. (2) To f u r t h e r reduce handling hazards, a l l t r a n s f e r s of powder throughout the wet stages are c a r r i e d out by pumping a water s l u r r y of the m a t e r i a l . (3) One of the p r i n c i p a l problems i n the development of n i t r o c e l l u l o s e smokeless powder i s that of s t a b i l i z i n g n i t r a t e d cotton so as to prevent spontaneous i g n i t i o n during storage. A s u p e r i o r chemical s t a b i l i t y i s a t t a i n e d by the a d d i t i o n of a s t a b i l i z e r to solvated n i t r o c e l l u l o s e . Since the

In Toxic Chemical and Explosives Facilities; Scott, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1979.


8.

CARROLL AND NICHOLS

Ball Powder

Process

173

molecular d i s p e r s i o n of n i t r o c e l l u l o s e i n a solvent i s an essent i a l step i n the g r a i n formation process, i t can be seen that (by using solvent c o n t a i n i n g the s t a b i l i z e r ) s t a b i l i z a t i o n i s a n a t u r a l consequence and that i t i s not necessary to supply completely p u r i f i e d ( s t a b l e ) n i t r o c e l l u l o s e f o r the BALL POWDER process. The p u r i f i c a t i o n and s t a b i l i z a t i o n of n i t r o c e l l u l o s e i n the BALL POWDER g r a i n i n g operation make i t p o s s i b l e to rework and r e s t a b i l i z e d e t e r i o r a t e d smokeless powder stocks. (4) The p o t e n t i a l energy of BALL POWDER i s adjusted i n the coating operation by the a d d i t i o n of n i t r o g l y c e r i n e . The n i t r o g l y c e r i n e i s added to the p r o p e l l a n t i n ranges of 10 to 40 percent. An emulsion of n i t r o g l y c e r i n e , solvent and water i s added and the powder absorbs the n i t r o g l y c e r i n e and s o l v e n t . N i t r o g l y c e r i n e i s a v i o l e n t e x p l o s i v e and i s s e n s i t i v e to heat and shock. In order to reduce the s e n s i t i v i t y and decrease the hazards of handling n i t r o g l y c e r i n e , i t i s used i n s o l u t i o n s with an equal quantity of s o l v e n t . A 50% n i t r o g l y c e r i n e and 50% e t h y l acetate s o l u t i o n when i g n i t e d u s u a l l y burns r a t h e r than detonates and cannot be detonated with a b l a s t i n g cap. The c h i e f danger i n the handling of t h i s s o l u t i o n i s that e t h y l acetate i s v o l a t i l e and upon evaporation w i l l leave a r e s i d u e of n i t r o g l y c e r i n e having i t s o r i g i n a l s e n s i t i v i t y . (5) Drying, which i s accomplished q u i c k l y i n a continuous dryer, e n t a i l s a minimum amount of powder i n process a t any time and a minimum exposure of o p e r a t i o n personnel a t t h i s stage of the process. S l u r r y Pump Design

Criteria

In the pumping of powder s l u r r i e s as i s performed throughout the wet stages of the process, c e r t a i n design requirements must be met. I t i s necessary when pumping s l u r r i e s of e x p l o s i v e s or l i q u i d s with a p o s s i b l e e x p l o s i v e containment to avoid c i r c u l a t i n g e x p l o s i v e s behind the i m p e l l e r o r running the pump with inadequate water flow. For t h i s reason open i m p e l l e r s without balance holes are r e q u i r e d . A l s o , a s p e c i a l t e f l o n l a n t e r n r i n g i s used. Seal water i s introduced a t a minimum r a t e of 1 gpm through a thermal flow switch, along the i m p e l l e r s h a f t , and i n t o the c a s i n g . The flow switch i s i n t e r l o c k e d with the motor s t a r t e r f o r the pump so that i n the event of low s e a l water flow, the pump w i l l be a u t o m a t i c a l l y shut o f f . The flow switch i s c a l i b r a t e d with an i n - l i n e rotameter which can a l s o be used to troubleshoot o p e r a t i o n a l problems. The r e a r s e a l r i n g on the pump i s removeable so that the e n t i r e area behind the i m p e l l e r may be f l u s h e d . Heavy duty thrust bearings are r e q u i r e d f o r a l l pumps. Pump design i s back-pull-out to avoid d i s c o n n e c t i n g p i p i n g when removing the pump i m p e l l e r . Equipment F a i l u r e P r o t e c t i o n Although the BALL POWDER process i s a simple one, a c e r t a i n



174

TOXIC C H E M I C A L

A N D EXPLOSIVES FACILITIES

amount of mechanical equipment i s necessary. Mechanical f a i l u r e i n equipment i n many cases can c r e a t e a s a f e t y hazard by generating heat which i n turn can cause i g n i t i o n or detonation. By sensing temperature and i n t e r l o c k i n g the sensor to sound an alarm and shut down the equipment, i t i s p o s s i b l e to e l i m i n a t e some hazards a s s o c i a t e d with mechanical failure. Examples of such i n t e r l o c k s i n the g r a i n formation stage of the process are: (1) high temperature shutdowns on lacquer pumps, (2) low flow alarms on mixer j o u r n a l s , and (3) c e n t r i f u g e bearing alarms. A continuous mixer i s used to d i s s o l v e n i t r o c e l l u l o s e i n e t h y l acetate to form lacquer. Lacquer pumps t r a n s f e r lacquer from the continuous mixer to the g r a i n e r s . The temperature of the lacquer i s already above ambient and any unwanted f r i c t i o n a l heat can cause a temperature excursion and p o s s i b l e i g n i t i o n . The p o s s i b i l i t y of i g n i t i o n w i l l be e l i m i n a t e d by p l a c i n g a temperature probe a t the packing gland assembly which w i l l shut down the pump when over-temperature i s reached. Similarly, the c e n t r i f u g e , which separates powder and water, has bearings which on f a i l u r e could overheat and i g n i t e the powder. A temperature sensor can shut down the c e n t r i f u g e when the bearing temperature r i s e s . The mixer bearings are handled i n a s l i g h t l y d i f f e r e n t way. The bearings are cooled by flowing water past them from a constant head water supply tank. I f water flow was l o s t i t would be p o s s i b l e f o r the bearings to overheat, thus c r e a t i n g a very hazardous c o n d i t i o n . To e l i m i n a t e t h i s p o s s i b i l i t y , a flow switch i s i n s t a l l e d i n the water l i n e to the mixer bearings. When flow i s i n t e r r u p t e d , an alarm i s sounded so that an operator can take c o r r e c t i v e a c t i o n before bearings overheat. As p r e v i o u s l y s t a t e d , the purpose of the solvent evaporation systems i s to remove the solvent from the lacquer p a r t i c l e without deforming the s p h e r i c a l shape of the p a r t i c l e . The l o s s of the l i q u i d l e v e l i n the evaporators w i l l r e s u l t i n a very s e n s i t i v e lacquer and could r e s u l t i n thermal i g n i t i o n of any r e s i d u e on the evaporator w a l l s . L e v e l c o n t r o l s are i n t e r l o c k e d with the steam supply to the evaporators to prevent thermal i g n i t i o n from o c c u r r i n g . In v a r i o u s a p p l i c a t i o n s i n BALL POWDER f a c i l i t i e s , non-explosion-proof v i b r a t i n g feeders are used to convey powder. At the present time, i t i s impossible to o b t a i n an explosion-proof feeder. The feeder's e l e c t r i c c o i l can burn out causing sparking w i t h i n the enclosure and p o s s i b l y i g n i t i n g powder or solvent vapors that have accumulated. To avoid t h i s p o s s i b i l i t y , a i r purge systems are i n s t a l l e d to prevent the buildup of e x p l o s i v e or flammable m a t e r i a l . The a i r purge systems a r e also i n t e r l o c k e d with the equipment so that i n the event of l o s t a i r flow, the v i b r a t o r w i l l be shut down and an alarm sounded.


8.

CARROLL AND NICHOLS

Ball Powder

Process

175


Manufacture and T r a n s f e r of N i t r o g l y c e r i n e As defined i n the c o a t i n g o p e r a t i o n , n i t r o g l y c e r i n e i s added to the hardened BALL POWDER to increase i t s energy p o t e n t i a l . N i t r a t i o n i n the n i t r o g l y c e r i n e f a c i l i t y i s accomplished by drawing g l y c e r i n e to an i n j e c t o r , the motive f l u i d f o r which i s n i t r a t i n g a c i d . The a c i d i s precooled to approximately 0°C upstream of the i n j e c t o r and serves as both a reactant and a heat s i n k f o r the exothermic r e a c t i o n . Even with the c o o l i n g provided by the a c i d , the n i t r a t i o n temperature i s r e l a t i v e l y high, 47°C. At t h i s temperature, the r e a c t i o n i s e s s e n t i a l l y completed i n the i n j e c t o r . The r e a c t i o n temperature i s maintained at about 47°C v i a a pneumatic c o n t r o l v a l v e , which modulates the flow of g l y c e r i n e to the i n j e c t o r . I n s u f f i c i e n t a c i d flow to the i n j e c t o r w i l l r e s u l t i n a temperature excursion ( l o s s of heat sink) and a l o s s of vacuum i n the n i t r a t o r . The temperature excursion may r e s u l t i n pressure rupture o f e i t h e r an a c i d rotameter, an i n j e c t o r l i n e , or the n i t r o g l y c e r i n e c o o l e r due to the r a p i d e v o l u t i o n of decomposition gases. A vacuum breaker valve i s provided to vent the i n j e c t o r vacuum and thus stop the flow of g l y c e r i n e i n the event the vacuum drops too low. The i n j e c t o r i s a l s o equipped with a high and low temperature c o n t r o l loop which w i l l stop the n i t r a t i o n i n the event of a temperature excursion. However, the p o t e n t i a l f o r detonation may also e x i s t i n the area of the c o o l e r downstream of the i n j e c t o r due to a gradual l o s s i n a c i d flow r e s u l t i n g i n the l o s s of turbulence i n the i n j e c t o r t h r o a t . This l o s s of turbulence w i l l i n turn r e s u l t i n an inadequate mixing of r e a c t a n t s and i n l o c a l i z e d "hot spots." The p o t e n t i a l e x i s t s i n t h i s s i t u a t i o n f o r thermal i n i t i a t i o n of c o a l e s c i n g n i t r o g l y c e r i n e d r o p l e t s as e i t h e r a fume-off or detonation. The temperature sensors l o c a t e d here w i l l a l e r t the operator that the a c i d flow has decreased before i t can be sensed a t the i n j e c t o r . A f t e r the n i t r o g l y c e r i n e i s manufactured, i t i s combined q u i c k l y with e t h y l acetate to reduce the s e n s i t i v i t y and decrease the hazards of handling n i t r o g l y c e r i n e . Therefore, only a small amount of detonable n i t r o g l y c e r i n e i s i n the system a t any one time. The t r a n s f e r of n i t r o g l y c e r i n e presents s e v e r a l p o t e n t i a l l y hazardous c o n d i t i o n s f o r which design c r i t e r i a has been e s t a b l i s h e d . For example, no screwed connections f o r f i t t i n g s are allowed i n n i t r o g l y c e r i n e s e r v i c e and a l l welds are inspected f o r cracks. This reduces the p r o b a b i l i t y of detonation by e l i m i n a t i n g pinch p o i n t s . The handling hazards of n i t r o g l y c e r i n e a r e f u r t h e r reduced by educting, r a t h e r than pumping, the s o l u t i o n i n t o the c o a t i n g s t i l l with water. Further, the eduction l i n e i s equipped with a flow switch so that i n the event that water flow i s i n t e r r u p t e d and s u c t i o n i s l o s t , the l i n e w i l l be a u t o m a t i c a l l y f l u s h e d .


TOXIC C H E M I C A L

176

A N D EXPLOSIVES FACILITIES


Continuous P r o p e l l a n t Drying The dry processing of the powder i s more hazardous than those described p r e v i o u s l y f o r the wet stages of the process. In the continuous d r y i n g of BALL POWDER, dewatered powder i s fed i n t o a s e r i e s of v i b r a t i n g pan conveyors. Fresh a i r i s preheated and blown i n t o an a i r d i s t r i b u t i o n manifold where tubes d i r e c t the a i r flow i n t o the powder. An aerated bed i s obtained by c o n t r o l l i n g the powder flow r a t e , the pan conveyor v i b r a t i o n speed, and the heated a i r supply. The a i r s u p p l i e s the heat f o r evaporating the water. The water vapor i s removed with the exhaust a i r by vacuum t r a n s f e r . The a i r and water temperatures are c o n t r o l l e d a t 77°C to prevent high temperature which could cause i g n i t i o n of the powder. The instantaneous f l a s h point of the powder i s about 165°C. Only the steam i n the heating c o i l s exceeds 160°C. Therefore, i t i s a standard p r a c t i c e to l o c a t e the heating c o i l s and a i r blowers a t a safe d i s t a n c e from the dryer i n l e t to prevent the p o s s i b i l i t y of high temperature steam from coming i n t o contact with the powder. As an a d d i t i o n a l safeguard, f u s i b l e l i n k devices i n s t a l l e d i n the exhaust ducts w i l l automati c a l l y a c t i v a t e the c l o s i n g of the c o n t r o l v a l v e i n the steam l i n e feeding the a i r supply u n i t before the a i r temperature becomes excessive. A l s o , the temperature c o n t r o l s f o r the supply u n i t s are i n t e r l o c k e d to prevent the supply blower motors from s t a r t i n g i f there i s steam i n the heating c o i l s . This prevents an i n i t i a l high r a t e of r i s e of temperature. A normal problem encountered i n the manufacture of BALL POWDER i s the generation of a c e r t a i n quantity of " f i n e s " ( l e s s than 0.009" diameter). In order to supply enough heat to maintain the e s t a b l i s h e d drying temperature of 77°C, a c e r t a i n quantity of " f i n e s " and low d e n s i t y powder may become entrained i n the exhaust a i r . A s e r i o u s hazard w i l l e x i s t i f the entrained powder f a l l s out of the exhaust a i r stream and accumulates i n the ducts or the exhaust fan shroud. To prevent t h i s problem, the exhaust manifold of each dryer u n i t has a l a r g e cross sect i o n a l area a t the e x i t port. This reduces the e x i t v e l o c i t y of the exhaust a i r , minimizing entrainment of s o l i d s . As the exhaust a i r leaves the e x i t p o r t , the cross s e c t i o n a l area of the duct decreases, which increases the a i r v e l o c i t y above the minimum t r a n s p o r t v e l o c i t y . This prevents s o l i d s from f a l l i n g out of the a i r stream and s e t t l i n g i n the duct. The a i r i s then p u l l e d i n t o high e f f i c i e n c y cyclones which separate any entrained powder from the a i r . In order to insure high s e p a r a t i o n e f f i c i e n c y , f r e s h bleed a i r i s added to the exhaust a i r to maint a i n a constant a i r flow (the pressure drop across the cyclone v a r i e s as the square of volume handled). The a i r exhausted from the cyclones feeds i n t o a s i n g l e wet scrubber which scrubs the exhaust a i r with water to remove any g r a p h i t e or t r a c e s of powder not removed by the cyclone. T h i s type of system allows



8.

CARROLL AND NICHOLS

Ball Powder

Process

177

high volumes of drying a i r to be s a f e l y and e f f i c i e n t l y used f o r both high d e n s i t y and low d e n s i t y powder. (Low d e n s i t y powders are more e a s i l y entrained i n the exhaust a i r . ) The f r e s h bleed a i r introduced i n t o the dryer exhaust ducts i s heated to prevent the condensation of any n i t r o g l y c e r i n e vapors i n the exhaust a i r (a small amount of n i t r o g l y c e r i n e evaporation from the powder i n the l a t t e r dryer zones i s not unusual). The heated a i r assures that any n i t r o g l y c e r i n e i n the exhaust a i r remains i n the vapor s t a t e u n t i l i t can be removed by the wet scrubber. In areas where dry powder i s handled, the buildup of s t a t i c e l e c t r i c i t y presents a s a f e t y hazard. A s t a t i c charge could p o s s i b l y i g n i t e or detonate p r o p e l l a n t i n the dry s t a t e . For t h i s reason, m a t e r i a l s used i n these areas are conductive and p r o p e r l y grounded. F l o o r i n g and footwear must a l s o be conductive as o u t l i n e d i n the Department of Defense Safety Manual. Conduct i v i t y t e s t s are made p e r i o d i c a l l y to insure that there i s proper p r o t e c t i o n against s t a t i c charge b u i l d u p . N i t r o c e l l u l o s e smokeless powder i s an extremely e l e c t r o negative m a t e r i a l , and t h e r e f o r e , produces s t a t i c e l e c t r i c i t y when brought i n t o contact and separated from almost any other m a t e r i a l . During the course of d r y i n g , and handling the powder a f t e r d r y i n g , BALL POWDER could a c q u i r e a c o n s i d e r a b l e charge. To prevent t h i s from o c c u r r i n g , BALL POWDER i s "glazed" with g r a p h i t e and handled i n grounded c o n t a i n e r s so that i t cannot accumulate an a p p r e c i a b l e s t a t i c charge. Fire Protection The f i r e water d i s t r i b u t i o n system i s kept p r e s s u r i z e d by means o f a jockey pump. In the event of a s p r i n k l e r t r i p , three l a r g e d i e s e l d r i v e n pumps come on l i n e as needed to supply the tremendous q u a n t i t y of water which may be r e q u i r e d . In order to prevent the water pressure from dropping, which would r e s u l t i n low water flow to the s p r i n k l e r n o z z l e s immediately a f t e r they are opened, an e l e c t r i c switch panel allows the d i e s e l s to be s t a r t e d d i r e c t l y from an e l e c t r i c n o t i f i e r system. This permits the d i e s e l s to get the s t a r t s i g n a l about the same time water begins to flow which reduces the unwanted i n i t i a l pressure drop. In areas where the p o s s i b i l i t y of f i r e i s the g r e a t e s t , a high speed u l t r a v i o l e t d e t e c t i o n system i s employed. The u l t r a v i o l e t "eyes" detect the presence of a flame and are interconnected with a high speed water deluge system. In some areas the f i r e d e t e c t i o n devices have process shutdown c a p a b i l i ties. The d e t e c t o r s are s i t u a t e d such that the e n t i r e hazardous area can be monitored a t a l l times. They are equipped with a i r s h i e l d s that not only c o o l the d e t e c t o r but a l s o blow clean a i r across the face o f the l e n s , keeping any dust from accumulating on the l e n s , which assures d e t e c t i o n c a p a b i l i t y . Further, the d e t e c t o r s have a b u i l t - i n t e s t lamp which serves as a check of



178

TOXIC CHEMICAL AND EXPLOSIVES

FACILITIES

the detector tube module and a l s o makes i t p o s s i b l e to check f o r lens obscuration. The system i s one that i s h i g h l y r e l i a b l e and which w i l l sound an alarm i n case of a broken wire or m a l f u n c t i o n of any c r i t i c a l component of the system. The f i r e p r o t e c t i o n system c o n s i s t s not only of a deluge system a c t i v a t e d by the u l t r a v i o l e t sensors, but a l s o of f u s i b l e l i n k type f i r e systems. The deluge system has a t r i p mechanism from mercury checks a c t i v a t e d by h e a t - a c t i v a t e d - d e v i c e s , a manual r e l e a s e on the deluge v a l v e , a pneumatic remote t r i p s t a t i o n , and an e l e c t r i c a l push button along with the e l e c t r i c a l t r i p mechanism from the U/V d e t e c t o r s . The remote t r i p s t a t i o n s are l o c a t e d by escape routes so i t i s p o s s i b l e f o r the operator to t r i p the systems as he e x i t s the b u i l d i n g without exposing himself to f u r t h e r danger. Also used to help c o n t a i n p o t e n t i a l f i r e i s f i r e p r o o f i n g of s t e e l tanks. Any s t e e l tank c o n t a i n i n g flammable l i q u i d s has the s t e e l supporting members covered with f i r e p r o o f i n g m a t e r i a l having an underwriter's l a b o r a t o r y r a t i n g of at l e a s t two hours. T h i s w i l l prevent a tank from c o l l a p s i n g and f u e l i n g a fire. Any areas which have flammable l i q u i d s are equipped with a foam f i r e f i g h t i n g system. The foam system i s a c t i v a t e d by f u s i b l e l i n k s or manually. The f i r e truck has a foam eductor system which can be used to e x t i n g u i s h flammable l i q u i d , or Class I I f i r e s . The foam i s educted out of f i v e g a l l o n buckets and mixed with the water stream i n the eductor. Summary Prevention of l o s s of personnel or property i s more than j u s t a s o c i a l or moral o b l i g a t i o n . Safety i s as c r i t i c a l to the e f f i c i e n t operation of a chemical plant as any other f u n c t i o n . The manufacture of e x p l o s i v e s i n v o l v e s s p e c i a l hazards which must be minimized through i n t e l l i g e n t s a f e t y engineering. RECEIVED November 22,

1978.


Safety Design Criteria for the BALL POWDER Process - American

Recommend Documents