Mr. Fish:-I might say for the information of Mr. Wilson that in the Pillsbury Hospital, built a few years ago at Concord, N. H., the water heating apparatus was planned and installed by an engineer from St. Paul. It was erected upon the 1-pipe or circuit system. A 4-inch main pipe was used, and the construction of the apparatus on this plan was looked upon at that time with doubt by local fitters. After completion it was very closely observed in its operation, and I personally examined the system and with some others reached. the conclusion that the apparatus was a success and that we had learned something. The apparatus has been working about six years and has been very satisfactory. The indirect heating used in this building was on a separate circuit main pipe.

Mr. Dean:—I want to correct myself in what I said a little while ago. In the 1-pipe system of which I spoke the returns were brought into the side of the bottom of the main by eccentric T's. I also wish to ask Mr. Fish if he has in his experience had the same result on a low fire that he did in the instance referred to; the first radiator being fairly warm and some of the further ones being cooler?

Mr. Fish:-With reference to my own house I must answer no; I did not. Of course, when the fire is low the radiator at the extreme end of the system is not as warm as the first radiator on the line. That is equally true with the 2-pipe system. When the apparatus is working and the temperature of the water stands at the boiler about 170 degrees, you cannot notice any particular difference in temperature in the radiators. There must, however, be some difference in order to cause circulation, but the difference in temperature is not any more perceptible than that experienced on a 2-pipe job.

Mr. Dean:-Your main rose from the boiler to the last radiator? Mr. Fish:-No; the main pipe was carried level, with the exception of the last ten feet, when it was pitched toward the heater for the purpose of draining.

Mr. Payne: As the discussion is drifting to examples of the various methods of doing this class of work rather than a discussion of the merits of the various systems mentioned in the question, perhaps I will be allowed to give an illustration of a job I put in some time ago. It was a store where we had to lace the heater and heat the store and room above it. The pipe rose up from the heater and pitched down from the highest point directly over the heater. We took an air pipe from that point. We supplied the radiators up-stairs and returned them to the same main and also dropped two other radiators to the same level as the boiler and took a separate return

from them and carried it back to the boiler. We reduced the circuit main that ran overhead, so that when the end of the main got back from the boiler it, in conjunction with the return main underneath, would have the same capacity as the main leaving the boiler. Of course the radiators on the ground floor would not circulate at first as quickly as the radiators up-stairs, but ultimately, when the circulation was fully established, there was very little perceptible difference in the radiators down stairs and those above. I think the I-pipe circuit system is more particularly applicable to pressure hot water work. I put in a pressure hot water job the other day. I laid the work out for a man some distance from the city where I am located. But it was the first time he ever installed a system of this kind. He reversed every one of the radiators, connecting the flow end into the first fitting and taking it out on the side, bringing the return back and into the top of the main. When I got down there I felt rather bad over it, of course. We did not have time to alter it. I said, "let us try it." We put the pressure right on it and the job is working satisfactorily to-day. (Laughter).

Mr. Quay:-I suppose that hot water under pressure is a little off the subject, but I am glad it has been referred to. A good many people have advocated the hot water pressure system, and the reason they advocate it is because it is cheap. I went to the expense last winter of testing a job in my own house. I gave it a thorough test in order to see whether it is safe to advocate a hot water job under pressure, and I came to the conclusion that it is not safe to recommend it to the ordinary house-holder.

Mr. Fish:-I would like to shake that man's hand. I have always championed the cause of low pressure hot water heating and assured my friends that there is nothing to be gained in doing hot water work under pressure. I have been through it and speak from experience. Nothing is accomplished by putting a safety valve on the expansion tank. It is a dangerous practice and shows lack of knowledge. If I were a law maker, I would make it a criminal offence to put a valve on the expansion tank of a low pressure water heating apparatus. This practice makes the apparatus more dangerous than if steam were employed, for in erecting a steam apparatus the fitter will put on automatic appliances to govern the pressure and draft, rendering the apparatus practically safe, while with the expansion tank of a hot water job closed to the atmosphere for the ostensible purpose of getting high temperatures and assisting the circulation an element of absolute danger is introduced. I had a case last year where a fitter came to me and said, “I propose

to put a safety valve on the expansion tank and by that means increase the circulation." I advised against it and pointed out to him his wrong idea of the principles of water circulation. Some years ago I met a case where indirect radiators were broken because the fitter had erected his apparatus to operate under pressure, placing a safety valve on the expansion tank. The excessive pressure from expansion of the water caused them to break, the valve failing to act. When you realize the excessive pressure which is exerted on a job when run under the closed tank system and the danger of bursting a boiler, or perhaps a radiator in a parlor, and doing bodily injury, I cannot understand why it is practiced, and it behooves every member here to discountenance this practice. The fitter will feel more comfortable if he leaves the safety valve off the tank and erects his work on the low pressure or open tank principle, thereby avoiding chances of becoming liable for an accident.

Mr. Payne:—I did not put the safety valve on the expansion tank. I put it on the boiler. (Laughter). Another thing; I do not approve at all of pressure work. I am altogether opposed to it, but there are some conditions under which it may be necessary, and this was one of them.

XXII.-TOPIC No. 4.

Is it practical or economical to use a fan system in connection with a hot air furnace?

Mr. Jellett: This topic has been pretty thoroughly gone over in Mr. Kramer's paper.

XXII. TOPIC No. 5.

Which is the better practice in a system of hot water warming combining both direct and indirect radiation—to supply all from the same system of mains or separate mains to direct and indirect radiators?

Mr. Fish:-In erecting hot water work it has been my practice usually, where systems of both indirect and direct heating are employed, to run the indirect system on a separate main from the direct system, my reasons being that a better circulation is produced, and the indirect system, being placed on a separate main pipe, can be closed off, repairs made, or operated separately from the direct system, without its being interfered with.

Mr. Jellett:-That has been my own experience; when using indirect radiation and direct you can get better service by separating the mains. It is difficult to so adjust a system of hot water piping that you can feed direct and indirect equally well from the same

main. In a recent plant we ran separate mains to the direct and to the indirect. There are good reasons for that. You get better flow of water, and secondly, on account of the use of the house itself, the piping is so arranged that the indirect system can be drained independently of the other, so that we can use the boiler and the direct radiators to keep the house tempered and drain the balance of the system. There are one or two radiators in the bay windows of the living rooms hidden behind screens. My experience with this system has been that it has been very much more satisfactory than coming from one main.

Mr. Fish:-My practice has been similar; that is, I have always arranged the indirect stacks with two valves, with draw-off cocks for emptying purposes, in case repairs were needed. I would like to ask the members what experience they have had where they have used valves with small holes in the seats on radiators for hot water heating. Many manufacturers are now putting a small hole in the seat of their valves to prevent freezing, and my experience has been that the hole through the seat of the valve permits of sufficient circulation to keep the radiator as hot when closed off as when the valve is fully open. I know one instance where a fitter installed an apparatus and used valves having small holes in the seats, and his customer complained that he could not shut off his radiators, saying the valves were defective, and the fitter was obliged to have the holes in the valves soldered up and made tight before he could collect the balance of the money due him on the contract. Many fitters are using radiator valves with holes in the seat, it being stated by manufacturers that it prevents radiators from freezing, but as it spoils the usefulness of the valves for the closing off of the radiator, I do not think the practice a commendable one, as it causes the fitter much trouble and annoyance. There is not much danger from freezing, if ordinary precaution is exercised.

XXII.-TOPIC No. 6.

What are the advantages, if any (other than original cost of construction) in a 1-pipe installation over a 2-pipe or a 2-pipe relief system?

Prof. Carpenter:-I had occasion this last year to make a good many inquiries respecting the practice in this country and having all sorts of answers and opinions I came to the conclusion that it was largely a matter of practice of workmen: that if the workmen were accustomed to a 2-pipe system it was cheaper to put that in, and if they were not, that the other was cheaper.

Mr. Jellett:-I think it is more the universal practice in the West than it is in the East, and I think in view of that fact Mr. Quay would be much better posted than we are here. I would ask for the best experience from the West.

Mr. Quay: We do nearly altogether I-pipe work, and in office buildings and buildings where we have room in the attic we usually heat with the mains in the attic and we find the results are perfectly satisfactory, while we often hear men who do not use the I-pipe work say that it won't work. We think that if they would take the time to come and examine some of the jobs done on the 1-pipe overhead system they would have to take that back, because they do work perfectly satisfactorily. One thing is necessary, however, which Prof. Carpenter has referred to. It is necessary to be more careful in the construction in order to have the 1-pipe system work than it is in the 2-pipe system. The fact of the steam going through the arm of the radiator in one direction and the water going back through it shows the necessity of being very careful in regard to the sizes of your arms and the pitch, while I do not think they have to be as careful where the steam is following the return. Of course I do not like to say very much about the first cost being less, because I do not think that is what engineers should talk about. I think we make a mistake when we put that matter first. I think the first thing we should advocate is doing the work right, and let the first cost come in as a secondary matter. (I was sat down upon the other day on that point, but I did not make myself quite clear. My main idea in advocating the conduit system was that we should advocate the best system first and then the matter of cost.) We have constructed a great many plants for different classes of buildings, especially the larger office buildings, with the 1-pipe system, and I could give you, if we had time, an illustration of some of this work in twelve to sixteen story buildings, where we carry one main up into the attic with the distributing main in the attic and supply down from that point and connect to the return in the basement—usually suspended.

Mr. Fish:-In doing this 1-pipe work is it the question to pitch the radiators toward the main? Do you have any particular pitch? Are the outlets of the radiators specially tapped-that is large tapping-where you use this system?

Mr. Quay: The outlets are larger than the pipe. The radiator is pitched towards the main.

Mr. Jellett: I would like to ask what is the usual practice in the West with the 1-pipe system as to the amount of back pressure? I