July, 1941
INDUSTRIAL AND ENGINEERING CHEMISTRY
highly complimented, and the citizens of St. Louis should be appreciative of their efforts in fostering a program for the elimination of smoke.
Enf orcernent
't
On April 8, 1940, the Board of Aldermen courageously passed the ordinance under which the Division of Smoke Regulation is now being operated. It is now a matter of enforcement. The mere passage of this ordinance, however, does not ensure success in the elimination of smoke. I n addition there must be a properly organized and manned division to see that the provisions are met. There is no romance in the enforcement of the ordinance; it is the unrelenting, dayby-day attention to detail that brings success. Every complaint must be followed up and checked. Every installation must be inspected and approved. A courteous and understanding attitude must be taken toward all violators. However, this attitude should never reach the point where it becomes favoritism. Besides the supervision of the equipment, a continuous and thorough check must be made upon the type of fuel being used. The results obtained, which have provoked so much comment, have been due not only to the ordinance but to the effectiveness of the enforcement program. The enforcement must be logical and be so designed that the advantages secured must be maintained and additional results obtained. This work requires men with special training and experience. They are not easy to procure. The Division of Smoke Regulation in St. Louis has such a personnel. They are
technically trained men of the highest integrity with years of experience and the ability t o deal with the general public. T o them belongs a great measure of credit for success. They are the first line of defense; they are the ones whom the public rarely hear about but upon whose shoulders rests a large portion of the responsibility for the success or failure of the program. The history of this last campaign for the elimination of smoke in St. Louis shows that many individuals contributed to the success attained up to this point. It was a movement backed by citizens, supported and encouraged by the press and radio, and requested by the business interests. Many names should be mentioned, but the thought I desire to convey is that it was a movement of a community that had been aroused and whose determination was such that results were inevitable. One other element was also necessary for the successful conclusion of any civic movement of this character. The citizens, the press, and the business interests must have the honest and sincere cooperation of the city administration. No program would be successful or can be successful unless those administering the affairs of the community are willing to enforce the provisions of the ordinances in a manner devoid of all criticism; no favoritism can be shown and no special privileges can be granted t o anyone. Once initiated, the program has to be carried to a conclusion, irrespective of what may happen to those responsible for the administration. Therefore, any program that may be contemplated requires all the elements enumerated and in addition it requires political courage.
OSBORN MONNETT,
M
.
OST ordinances prohibit dense smoke except for 6 minutes in any one hour, during which the fire is being cleaned or a new fire is being built. Primarily phrased to take care of hand-fired furnaces, this law has stood the test of time and still serves as a standard to be attained in furnace operation. Fortunately hand-fired furnaces are rapidly becoming obsolete, a t least in installations carrying a load of more than 1200 square feet of steam radiation or its equivalent. With a properly set and operated mechanical stoker the task of operating within the 6-minute clause becomes easier; there has even been some disposition to shorten the time or to prohibit a certain amount of smoke not read as dense smoke. For measuring smoke density, nothing has come into general use to take the place of the Ringelmann chart, despite its crudities. Density is divided into five grades (Nos. 1 to 5) with 20 per cent variation; No. 3 grade is universally considered dense. Aside from the human element which enters into all Ringelmann observations, the thickness of the column of smoke is always a matter of contention; obviously, the larger the diameter of the stack and consequently the more smoke looked through by the observer, the denser the readings will be. If a stack makes just 6 minutes of No. 3 smoke in one hour, the smoke density of the reading will be 6 per cent. If the stack emits continuously a No. 2 smoke, which is not pro-
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56 West Washington Street, Chicago, 111.
hibited by most ordinances, the density will be 40 per cent or almost seven times as much smoke. Such performance is often met with in the case of improperly set or overloaded stoker settings. There is no question but that ordinances of the future will be stricter in requirements and also that technical advances will enable plants still to comply with such requirements. Ordinances should be as simple as possible and confined to prohibition clauses and defining limits of permissible variation. To accompany the ordinance, a code should be established fixing minimum headroom, combustion space, flame travel, breeching sizes, stack heights, etc., not written into the ordinance but administered by the city official in charge when issuing permits. Once written into an ordinance, a measure becomes fixed; but a code requirement can be changed a t will, according to experience or changes in the art of furnace design. It is seldom that a code requirement is questioned if based on good engineering practice for all are interested in obtaining as good results as possible in any given case. No smoke ordinance should be passed or revised until a careful study has been made by a competent authority, embracing all angles of the local problem. Geographical location has an important bearing on what is written into an ordinance. In a city removed from coal deposits so that comparatively high freight rates are in effect on
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INDUSTRIAL AND ENGINEERING CHEMISTRY
all coal, it is possible to set up fuel requirements and enforce them in a code without much opposition. Owing to the uniformly high freight rates the spread between high- and lowvolatile coal is not great and opposition i s reduced. Thus for many years Chicago has enforced a code ruling requiring lowvolatile coal on hand-fired furnaces carrying 1200 square feet of steam radiation or more. On the other hand, with a city located near an abundant supply of cheap high-volatile fuel, any drastic fuel requirement must necessarily be written into the ordinance and become a law in order t o be successfully enforced. Such was the situation of St. Louis, which recently attracted nationwide attention by limiting all fuel on hand-fired furnaces to not more than 23 per cent volatile. This ruling was all the more revolutionary because i t included private residences ia the regulation, a class of smoker which has always been exempt from any restriction. It was inevitable that residences and other small miscellaneous plants should eventually come under a smoke ruling. As industrial plants, have gradually been cleaned up over the years, a larger proportion of the smoke of cities is coming from the heating plants. Sometimes as much as 60 per cent or more of the total smoke comes from this source. Any complete cleanup in a city would be impossible without taking this part of the problem into consideration. Smoke from domestic fires is more objectionable than that from other sources. The volatile is distilled off a t a comparatively low temperature and is not alnmys thoroughly broken up into its constituent elements. As a consequence phenols and other acid compounds are present, especially in the thick yellow smoke frequently seen issuing from domestic chimneys. This type of smoke produces an irritating effect on the mucous membrane of the nose and throat and predisposes t o acute respiratory diseases, sinus infections, etc. In addition, the large flakes of soot occlude sulfur dioxide from the burning sulfur in the coal and act as a carrier, during which time oxidation takes place to sulfurous acid. This causes the corrosive effect noticeable on the metalwork of buildings and the damage to household fabrics. When it is remembered that this type of smoke is discharged a t low levels in closely built up residential sections with ready access to open bedroom windows and the like, the importance of this source of smoke can be realized. The first line of attack on this problem was education. Years ago widely publicized tests showed that remarkable reduction could be made in smoke from household furnaces by using the coking and alternate methods of firing, by starting fires from the top, by cracking the fire door, etc. Campaigns of education were tried in cities all over the country, some of them on a very elaborate scale. Even now certain cities are in the midst of such a campaign calculated t o teach people the proper methods of firing soft coal. Most of these campaigns have shown inappreciable results. The turnover in personnel is so great that the efforts have come t o
Vol. 33, Ne. 7
naught when it relates t o the great mass oE people needing instruction. Oil, gas, and by-product coke are important factors in the domestic situation, especially in the better class of residences, It is in the cheaper class, with a miscellaneous assortment of stoves, ranges, heaters, open fireplaces, etc., that the real problem lies. In most localities coal. is and will continue to be the basic fuel, and this emphasizes the importance of the small stoker wherever it can be applied, I n the miscellaneous class of heaters too small for stokers, smokeless fuel is the ideal solution, The action of St. Louis, which will no doubt be copied by many other cities of the Middle West, has caused a revival of interest in smoke abatement and has brought questions into prominence of a technical nature. A ruling similar to that of St. Louis means the importation of low-volatile coal or the manufacture of a processed smokeless fuel. If the location is such that low-volatile fuel can be imported a t a reasonable price, both methods of solution will find application; if the location is such as t o make low-volatile fuel prohibitive on account of freight rates, processed fuel is the logical answer. It is well t o consider the effect on the fuel situation if all cities in the Middle West should have recourse to low-volatile coal as a solution of their heating smoke problems. Certain facts are apparent: 1. The supply of low-volatile coal i s limited. 2. The freight hauls to most parts of the country are long and expensive. 3. Deliveries are liable to interruption through bad weather conditions, strikes, eto. 4. So-called low-volatile coal is not inherently smokeless and hence can be considered only as a compromise until more perfect solutions are made available. 5. Local fuel interests are upset, with consequent disruption of economic conditions. I n power plant design it is considered good practice to arrange a plant so that the local fuel of the district is used efficiently. In like manner it is good engineering t o supply any demand for smokeless fuel by the utilization of the local coals cheaply available to the locality. This has already stimulated interest In fuel processing and is bringing about the beginning of a new industry. Processing local coals will avoid disruption of local mining interests and remove the major part of the opposition usually met with in making any radical rulings. So we are approaching a new era in smoke abatement, an era in which the domestic furnace will be held accountable for the important contribution it makes to the atmosphere of the citics. The word “abatement” is being discarded for the word “elimination”. Smoke ordinances of the future will be written t o limit the emission of Nos. 1 and 2 smoke on the Ringelmann scale and the amount of solid products of combustion not classed as smoke.
