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REPORT OF SUB-COMMITTEE ON TEMPORARY SERVICE FOR MUNICIPAL SUB-SERVICE

AND OTHER CONSTRUCTION

CK NICHOLS, CHAIRMAN

DISCUSSION

MR. N. F. OBRIGHT, Chicago: When I was asked a few hours ago to abstract Mr. Nichols' paper in his absence, I realized for the first time that temporary construction work such as for buildings, municipal sub-surface work and the like, is quite a considerable source of income for central stations in the larger cities.

In this report an attempt is made to describe the manner in which electric motors are applied for some of these undertakings. Figures are given showing the amount of current used in various kinds of work; also the maximum requirements, operating characteristics of motors, etc. As the report is more or less one of reference for member companies who may have such construction work, it is well worth the time to read.

An effort was made to include some important figures on a large job which is being done in Chicago, namely, the digging of the Wilson Avenue water tunnel, approximately eight miles in length. This is an immense piece of work and affords data of considerable value to any one contemplating such work.

A very complete report of the progress of this job will appear in the Electrical Review & Western Electrician of June 3, and I would advise any one interested to study it carefully.

MR. FRANK E. RICHARDS, Newark, N. J.: We have the Passaic Valley sewage disposal plant construction through Newark. This construction extends for 25 miles and Mr. Nichols' report has shown a great many features that we discovered in this work.

The contractors who were constructing this plant, bid on

(SEE REPORT, PAGE 411)

the construction both by steam and electricity. The steam bids were the lowest and unfortunately the contractors using steam m several cases failed. The electrical contractors who were work ing on adjoining sections of this tunnel took the contracts off their hands at an advance price and used electricity in the construction So it seems that those who are bidding on and using electricity quite often succeed where those using steam tail

We received a revenue of approximately $80,000 for the year 1915, which covered the construction of about two thirds of the tunnel under electrical contracts. Our rate was about 14 cents per kw hr.

The large pumping plant at the edge of the Bay, requiring a load of approximately 200,000 kilowatt hours, was decided in favor of steam The Passate Valley Sewage Commissi n was averse to electric drive and the engineers guaranteed a price of & nal's per kw hr on the pun pang Our rate at that time did not permit of our securing the business If this work had been in Chicago we would undoubtedly have got it as the rate hicre on this class of work would have tavored us

Mr. Nichols has given us a lot of valuable data, and Eas shown us that the mixing and handling of concrete in the con struction of tunnel work and large bukh gs give us a destra' le load with a fairly hih kilowatt hour consumption Betrie drive also facilitates building in a congested territory where steam can not be used We have succeeded in securing all the building construction in Newark The sewage tunnel is our only extent ence in tunnel construction work

THE RESISTANCE HEATER AS A LOAD

BUILDER

BY E F COLLINS

DISCUSSION

MR. A. H. TRACY, Chicago: Yesterday afternoon we had a meeting here that started with Mr. Carlsen's paper on the manufacture of ice and ended at about 2000 degrees, with Mr. Hirshfeld's report of the Industrial Heating Bureau Committee.

We are used to sudden changes of temperature here, and I should say that the meeting could properly be described as a sort of "chills and fever" meeting. I think this paper falls within that range and it seemed to me as if that was a good way to classify the whole subject, because the paper reached me when my mind had been stirred into a feverish state of activity by the enormous amount of energy that it was possible to get if we could obtain this heating load, and left me somewhat chilled by the knowledge that I had gained absolutely nothing which would enable me to obtain that load. It seems to me that what we want to do when we go after power of this kind is to have some definite knowledge on which to start, and the state of the industry seems to require that we ask a good many questions in order to get the cloth from which we can cut the suit to fit the customer we are after. Under these conditions, I am going to confine my discussion to asking a few questions which, if answered, will I hope help me do a little more to land some more of this business. It looks big and apparently it is correspondingly hard to get.

The first thing I would like to ask is, "What is the best method of calculating the energy consumption and the installed capacity?" In my work I have approached that problem with the idea of calculating the various losses, that is, the radiation losses and the convection and absorption losses. If we add these heating losses together we will get a theoretical kilowatt-hour requirement and to match theory to practice it is generally neces

(SEE PAPER, PAGE 444)

sary to take those three quantities which we might call R, Canl A and add them together and then multiply the sum by K, which is our well known constant that stands for the knowledge we don't possess ourselves. Now, what is the value of a constant of that kind when it is applied to a problem of this character? I have applied the theoretical figures several times and I find that the constant is not a very constant quantity. That is merely because I don't know enough about the subject. I want some more information on the value of this constant, if I can get it from somebody.

Now, the next question is, "What is the insurance situation with regard to a lower rate for electricity than for gas" Two or three of the problems that I have had under discussion seem to show that the increase in insurance rates on enameling and heat ing ovens heated by gas very often runs from 15 cents down. Now, 15 cents on $100 of value will raise the insurance rate on some of these expensive buildings by a very material tactor, and I think it can be said that in some cases the amount of increase in insurance on a building that contains a gas heated oven will probably pay the cost of electricity to operate that oven at any reasonable price per unit. Up to the present time I have been unable to obtain any definite information from the insurance people as to what their probable attitude would be on the rele tion in rate due to a reduction in fire hazard One of the clams made for the electrical process is that it will materyally re face the fire hazard, and if it is properly installed it will entirely eliminate the explosion hazard The explosion hazard is of cour e, a pretty hard thing to figure on I once talked to an in who said that they never had explosions, and now I find that they all tell von the same story The second time I went to see my ran it must so happened that one of his ovens ca” e ont of the win w to meet re as I went down the street I believe the cost of ter oven was about $180 Of course, it stirred up a ta for 500 or 600 people who stot ped work and wat hed the Freer o me along. The explosion, while it did no sen uns dar did not kill anyone cost. I sunose what three p

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see his oven if I would come around at two o'clock. I had previously been talking to him about the fire hazard, which is one of the points you can dwell upon. He had never had a fire. I went around at two o'clock and he said, "Well! you will have to wait a little while until we get cleared out up there; we've just burned out." That was the second, and it so happened that I had another experience of exactly the same kind the very next day—that was three in a week. Now it seems to me from this point of view and the small amount of experience I have had, that the fire situation is as large a factor as the rate situation. Some one may have some knowledge of conditions in other cities that will help us on it.

Now, in figuring the cost of electricity versus gas or coke or anything else, there is no use of starting out with the idea that you are going to get anywhere if you figure on a B.t.u. basis, because you never will. In almost every case the cost of the heat necessary to do the enameling is an extremely small part of the total cost of the finished product. Take the automobile industry, for example: the cost of enameling the product, or rather that portion of it which is enameled, probably does not represent more than one percent of the cost of the manufacturer's output, and the fuel cost of the enameling process is only a small part of his total cost of enameling. It will at once be seen that we are dealing with an extremely small part of the customer's total cost, and it is undoubtedly true that even if the cost of electricity is as much as two or three times the cost of gas, the change will show a large saving if he can increase his total output in a given time by even a small percentage, because the profit he obtains from this small increase will more than pay the entire cost of his electricity. In other industries, of course, this is not the case, and the question then has to be worked out for each individual manufacturer's problem, as you find it. I don't believe that the automobile industry is by any means the only one that can be successfully attacked. The man you talk to is probably interested in the total profit that he makes out of his business, so you are talking of about one percent of what he is interested in and you must have your story pretty straight to interest him at all.

The largest talking point we will find, I believe, to be the question of safety. Now, I have been told that the electric oven. is perfectly safe and I have also been told that several of them

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