T/ s S 2149 U5 opy 1 Grain Dust Explosion Prevention UNITED STATES GRAIN CORPORATION In Co-operation with the Bureau of Chemistry UNITED STATES DEPARTMENT OF AGRICULTURE DUST from grain will explode when mixed with air in proper propor- tions and ignited by sufficient heat or flame. The hazards of a dusty and dirty plant are very great. The only safe guaranty against a dust explosion is to practice "good house- keeping " and keep your plant clean at all times. It is your duty to protect not only your property but the health and lives of your employes a-r'^ o u i 'I NEW YORK June 1920 n. ©f iP* Nuv 13 1921 N .\ M ..-^f ^j^^ ORGANIZATION OF DUST EXPLOSION PREVENTION CAMPAIGN In carrying on the dust explosion prevention campaign for the year 1919-20 the United States was sub-divided into four districts: Eastern, Northwestern. Central and Pacific Coast. The personnel of this cam- paign was as follows : UNITED STATES GRAIN CORPORATION Dr. J. W. T. DuvEL, New York, in Charge Mr. H. E. Roethe, Jr Washington, D. C. Mr. J. O. Reed Washington, D. C. Mr. H. R. Brown Washington, D. C. Mr. G. D. Wither Washington, D. C. Mr. E. L. Riley Buffalo, N. Y. Mr. p. L. Mann New Orleans, La. Mr. Vernon Fitzimons Minneapolis, Minn. Mr. Paul E. Brady Minneapolis, Minn. Mr. W. B. Lind Minneapolis, Minn. Mr. G. a. Hibbard Chicago, 111. Mr. G. H. Rice Chicago, 111. Mr. H. J. Helmkamp Kansas City, Mo. Mr. M. E. McCollam San Francisco, Cal. Mr. G. p. Bodnar Portland, Ore. U. S. DEPARTMENT OF AGRICULTURE Mr. D. J. Price, Engineer in Charge of Dust Explosion Investigations. U. S. Bureau of Chemistry, Washington, D. C. Dr. H. H. Brov^n, Organic and Physical Chemist, U. S. Bureau of Chemistry, Washington, D. C. GRAIN DUST EXPLOSION PREVENTION CONTENTS PAGE. Introduction 5 Educational Work 6 Pledge cards 7 Meetings in grain center 9 Cooperation with Canadian Government 9 Inspection of Plants 9 Improvement in condition of plants 13 Literature 15 Results of Campaign 18 Explosions during Campaign 19 Buffalo, N. Y 19 Port Colborne, Ont., Can 20 Kansas City, Mo 21 Spice dust Explosion 22 Aluminum dust Explosion 23 Boissevain, Man., Can 24 Buffalo, N. Y 24 Denver, Colo 25 Experimental Work 25 Theory of dust explosions 25 Density of dust cloud 25 Source of ignition 26 Velocity of propagation of explosion 26 Pressures developed in explosions 26 Conditions for explosions 26 Propagation of the explosions 26 Prevention of explosions 27 Large scale tests 27 Electrical equipment and dust explosions 2S GRAIN DUST EXPLOSION PREVENTION INTRODUCTION The Government first gave consideration to the dangers from grain dust explosions and fires, as a result of a disastrous explosion in a feed grinding plant at Bufifalo, New York, in 1913. As a result of this explo- sion, a series of investigations were conducted by the Bureau of Mines of the United States Department of the Interior, in cooperation with the milling and grain interests, with the view of determining the causes of such explosions and fires, and to devise methods for their prevention. Subsequently this project was turned over to the Bureau of Chemistry of the United States Department of Agriculture, and much valuable information brought together relative to explosions and fires in grain elevators, flour mills, threshing machines (^) in the Pacific Northwest and in cotton gins(^) of the South. The importance of continuing and extending these investigations was fully realized at the beginning of the war, in order that the country's food supply might be fully protected against the hazards of dust explosions and fires. Accordingly the United States Department of Agriculture and the United States Food Administration inaugurated an extensive educa- tional campaign, in the Fall of 1917, to provide the owners and operators of mills, elevators and threshing machines, with the information avail- able, so that the losses resulting from dust explosions might be reduced to a minimum. The necessity for this undertaking was strongly empha- sized by several disastrous dust explosions which occurred between March, 1916, and October, 1917, resulting in the destruction of four of the largest grain and cereal plants in the United States and Canada, to- gether with the loss of twenty-four lives. The dust explosion, together with the fire which followed, in one of these plants (Brooklyn, New York), was of special significance at the time in that it resulted in the destruction of a quantity of grain equivalent to bread rations for an army of 200,000 men for an entire year, and at the same time most seriously crippled facilities badly needed for loading grain for overseas shipment. (a) Department of Agriculture Bulletins 379 and 681, and Circular (b) Department of Agriculture Circular No. 28. The workmen in this plant were not generally familiar with the causes of dust explosions and fires and methods that could be adopted for their prevention. The United States Grain Corporation assumed financial control of the grain dust explosion campaign in July, 1919, to make sure that the Government's stocks of wheat were fully protected at all times ; other- wise the work would have lapsed June 30, 1919, with the termination of the war emergency provision granted by Congress to carry on this work as a part of the food conservation program. Since this time, the United States Grain Corporation, in cooperation with the Bureau of Chemistry of the United States Department of Agriculture, has carried on an exten- sive campaign to assist in removing dangerous conditions in plants carrying Government grain and flour stocks, and also to familiarize the grain and milling interests with the true nature and means of prevention of dust explosions and fires. The aim has been to lessen the inherent hazards in the grain industry. Throughout this campaign active cooperation has been given by many agencies and commissions engaged in explosion and fire prevention activities, and this opportunity is taken to acknowledge our indebtedness to these organizations, as well as to the grain and mill- ing interests, for the excellent assistance rendered. EDUCATIONAL WORK In addition to the regular inspection of plants carrying Government stocks, an efifort was made to impart to the employes of elevators and mills special information on the subject of dust explosions and fires. In the war emergency campaign all mills with capacity of approximately 50 barrels or more, and elevators over 25,000 bushels capacity, were visited. In the campaign carried on by the Grain Corporation attention has been directed primarily to plants where Government stocks were stored. The work has been extended, however, to outside plants as time permitted. The employes in the plants were acquainted with the causes by which explosions can be produced, with special reference to the simple causes within the control of the workmen, such as a lighted match, smoking, use of open flames, careless use of electric lights, etc. This was done in many cases by a direct " heart to heart " talk with the men either indi- vidually or in group meetings, on the working floors or in convenient parts of the plants. In order to familiarize the men with the extent of damage done by previous explosions, a series of specially prepared photo- graphs showing views of damaged plants in which there had been ex- tensive losses of life, grain and property were used. Whenever it was possible to assemble a number of the employes, either at the noon hour, or by special arrangement with the management, illustrated lantern slide lectures, showing results of experimental work, and also efifects of recent explosions, similar to photographs referred to 6 above, were given. In addition to the lecture, various demonstrations of dust explosions were produced to show the men how readily a violent explosion may result from an apparently simple cause. Two demonstra- tions in particular impressed the men effectively and aroused their interest. In one case a dust explosion was produced in a specially pro- vided miniature grain elevator by blowing dust onto an open flame, as shown in Figure 1. In the other, various common dusts were readily Fig. 1. Dust Explosion Demonstration — produced by blowing dust into an open flame in a miniature elevator. ignited by sifting through a piece of cheesecloth onto a burning match. In order to remove any doubt regarding the nature of the dust used m the demonstrations, the workmen were asked to collect dust from various parts of the plant. In many instances samples of the dust which the employe had to work with and handle daily were presented for testing. The effect of the explosion on the workmen in these cases was very marked. From expressions made by the men it could be seen that they would not forget the lesson and would do all they could to prevent dangerous conditions. Pledge Cards At the close of the lecture and demonstrations, or during the inspec- tion trip through the plant, the moral support of the workmen was enlisted by having them sign pledge cards as shown in Figure 2. UNITED STATES DEPARTMENT OF AGRICULTURE AND UNITED STATES FOOD ADMINISTRATION HAVE ALREADY SIGN ) A FELLOW EMPLOYEE) To prevent grain dust explosions and fires in the mills and elevators in which I am employed, 1 agree personally to obser\'e preventive measures and to use every effort and influence to induce others to lake all possible precautions. 1 make this promise in the realization that carelessness rnay result in loss o( life, loss ot (ood needed by the Nation, and destruction ol factories needed to produce food. Name Firm or Company- City — Failure to observe tKeee nay result in dust explosions or fires wh: nay cause loss of life and will cause loss ood needed by the Nation: I 1. Smoking and ligVited matches hi au&ed many of our greatest fires and mutches r th» i dusty mill or elevator. 3. Dust and dirt invite dust explosion The records show that there are six tim( as many 6res in dirty mills and elevators i pulleyi. [ whei 4. Elevator choke-ups are frequent causes of fires and explosions. In many cases choke-ups have led to fires which destroyed over a million dollars' worth of grain and property, all elc the; vol.. rvia • Mgh ouble. .ently Fig. 2. — Pledge card signed by workmen. (a) Front of card. (b) Back of card. A ready response was always secured and large numbers of these cards were signed by the employes. By so doing they promised to observe the precautions designed for the prevention of these explosions. The cards were forwarded to the Washington office, and their receipt imme- diately acknowledged, with the name and address of the workmen in- serted on the card, as shown in Figure 3. It is believed that the work- men adhered to their promises and were responsible in many instances for the removal of dangerous conditions which might have resulted in explosion and fire. UNITED STATES DEPARTMENT OF AGRICULTURE AMD UNITED STATES FOOD ADMINISTRATION Washincton, D. C. llr. iToe Taylor, 540 Tlorth T>unoaii Gt., Chioago, 111. Dear Sir: This is to acknov^ledge receipt of the card, recently signed by you, in which you personally agree to observe preventive measures and to use every effort and influence to induce others to take all precautions to prevent grain-dust explosions and fires in mills and elevators in which you are employed. By signing this card and carefully observing the pledge made thereon, employees of mills ancl elevators are actively cooperating with the United States Department of Agriculture and the United States Food Administration in their effort to SAVE FOOD AND WIN THE WAR. HERBERT HOOVER lyP Food Administrator D. F. HOUSTON Secretary of Agricuitu Fig. 3. — Card acknowledging pledge of workmen. 8 Meetings in Grain Centers In addition to presenting the dust explosion prevention work to the employes in the plants, it was considered desirable to acquaint the owners and operators with the hazards. As it was impossible to stage large-scale demonstrations all over the country, specially arranged motion pictures showing the results of large scale dust explosion tests, as de- scribed on page 27 , were shown to the grain men in various sections of the United States. While the small scale demonstrations of dust explosions served their purpose well, they did not show fully the rate at which an explosion might propagate through the plant. The motion picture reels also contained views of plants damaged by explosions and fire together with measures of prevention. The work was also pre- sented at conventions of fire protection, conservation, and similar asso- ciations. These conventions in many instances included not only grain men but firemen and insurance representatives as well. Numerous re- quests for presentation of the work were received from associations of firemen, in order to obtain information to assist in the prevention of dust explosions during the progress of fire fighting. Cooperation with Canadian Government In connection with the series of meetings held in the larger grain centers of the United States, as a result of a request from the Domhiion Fire Commissioner, a special dust explosion prevention meeting was held at Fort William, Ontario, in November, 1919. This meeting was attended by a large number of Government, provincial and city officials, as well as representatives of the Canadian grain and milling industries and insurance companies. Interest in dust explosion prevention was aroused in Canada by an explosion in August, 1919, in a large grain elevator at Port Colborne, Ontario, operated by the Dominion Government. The explosion was in- vestigated in cooperation with the Canadian Government officials and assistance rendered in the development of precautionary measures in the rebuilding of the plant. INSPECTION OF PLANTS As previously stated, this campaign was undertaken primarily for the protection of the Government grain and flour stocks against the hazards of dust explosions and fires. For this purpose, regular inspec- tions were made of the mills and elevators where Grain Corporation stocks were stored. Other plants were likewise visited frequently in order that the country's food supply might be fully protected. If conditions seemed hazardous in any respect, definite suggestions for remedying them were made to the official in charge of the plant. At the time of the first visit to each establishment, the inspector filled out a complete report on the following form provided for the purpose : GRAIN DUST EXPLOSION CAMPAIGN U. S. DEPART JIENT OF AGRICULTURE BUREAU OF CHEMISTRY AND BUREAU OF MARKETS District Date Inspected by Name of Company Office Address: Street City ' State Plant Address: Street City State Kind of Plant Mgr Supt Capacity No. Employees Construction: Wood Brick or Stone Concrete Steel. Remarks Bins : Open Covered Remarks Elevators : Wood Steel Combination Discharge to Bin: By Spout Belt Steel Conveyor. . . . Remarks Is Grain Cleaned before Storage? Yes No Remarks Dust Collectors : Location Cloth Cyclone Dust Room Remarks Suction System: On Bins Elevator Heads Conveyors Remarks Grinding Mills : Type Discharge to: Elevator Conveyor Bin Misc Any E.xplosion Protection Remarks Power Plant: Steam Electric Gasoline Misc.. . Lighting : Type Method of I nstallation Remarks General Condition of Plant Remarks Are Sweepers Employed ? General Remarks No. of Cards Signed No. of Circulars Desired. No. of Posters Desired Suggested Recommendations for Explosion and Fire Prevention Copies of this report were then sent to the district office and also to Washington, where they were recorded. On all subsequent visits the in- spector used a shorter form on which he noted only the rating for equip- 10 ment and maintenance and, when necessary, his recommendations to the company, as well as any changes in equipment since the preceding inspec- tion. GRAIN DUST EXPLOSION AND FIRE PREVENTION V. S. GRAIN CORPORATION U. S. DEPARTMENT OF AGRICULTURE District Date Inspector Name o£ Company Address: City State Manager Supt Kind of Plant Capacity Equipment Maintenance No. Employed. Recommendations Made to Recent Changes, Recommendations, etc In making these reports the following series of letters was used to classify the equipment and maintenance of the plant: Equipment Maintenance A. Modern, first-class, up-to-date appliances A. Good B. Fair, not new. ^- ^^^^ C. Old and not representative C. Poor A well-constructed plant, with modern mechanical appliances, would be given "A" for equipment. If precautionary measures were being carried out, and the explosion hazard recognized, the plant received "A" for maintenance. The classification for such a plant would then be "A A." If the maintenance was not up to the standard and the dust con- ditions looked after in only a " fair " manner, the classification would be " AB." If the plant was well equipped, but found in a dirty, dusty, or poor condition, it would receive a grade of " AC." In many cases, how- ever, equipment which was not strictly modern but was rendering satis- factory service was put in the " B " class, to distinguish it from that of newer type or design. If the plant was well maintained it would be classed as " BA," while " BB " and " BC " represented the intermediate and poor classes, respectively. Old type plants, in which the equipment had been installed for some time fell in the " C " class. When it was well maintained and particular attention was paid to the removal of the dust conditions, the plant would be placed in the " CA " class. Similarly, " CB " and " CC " represented the other grades of upkeep and mainte- nance. 11 United States Department of Agriculture SAVE LIVES United States Food Administration SAVE FOOD-SAVE PROPERTY Six Recent Dust Explosions and Fires in Mills and Elevators Killed 39 Persons and Injured 60. They Destroyed 2,500,000 Bushels of Grain, and Property Worth $8,000,000 Keep Your Mill and Elevator Free from Dust and Dirt Dust-free Mills and Elevators are Eixplo- sion-proof Viitf niwiiii: Elevator explosions and fires soiiietiwes destroy enough grain to feed a large army far a year <.