Practical steam and hot water heating and ventilation

Front matter

STEAM AND HOT WATER

HEATING AND VENTILATION

ALFRED G.KING

Preface

From a more or less experimental stage to one of an exact science has been the progress of the art of artificial heating and ventilation during the period covering the past twenty-five or thirty years. In the early days of this industry there were but few competent fitters located outside of the larger cities. However, of later years the above conditions have changed, due in a great measure to the constant advancement and education of the steam fitting trade. To-day it Is not an uncommon thing to find In a small city or town one or more steam fitters entirely competent to Install almost any kind of a steam or hot-water heating apparatus.

This education of the steam fitter has been accomplished largely by the frequent publication in the trade papers of much practical information, accompanied by drawings and data which could be readily understood by him.

The publication of a number of books on the subject of Steam and Hot-Water Heating and Ventilation has also been of great assistance to the steam fitter In his mental advancement. However, much of the matter contained in these books is too technical and of a nature too difficult to be clearly understood by a man of average education.

In presenting this w^ork the author wishes to give a brief history of the science of steam and hot-water heating and ventilation and the early methods of constructing work, and to describe and Illustrate the advancement and improvements over the earlier methods. By the illustrations, rules and explanations given, we shall aim to make plain to the steam fitter or apprentice the best methods of

8 PREFACE

estimating and installing heating work by any one of the modem methods or systems now in use.

To keep pace with the means and methods employed we must be continually studying and actively interesting ourselves in the improvements as they are brought out. The methods of a score of years ago have given place to other and improved methods and further experimenting and study by the wide-awake American mechanics are bound to result in still further progress.

To those authors and authorities from whose works we have quoted and to the manufacturers of heating appliances who have so kindly assisted us, we extend our thanks.

Our effort is not to criticise but rather to comment upon the various heating and ventilating systems in vogue at the present time and to instruct the steam fitter in a practical way regarding their application and installation.

We have also added such tables, rules and general information as will make this valuable as a reference book for the contracting steam fitter.

A. G. King.

October, 1912.

Chapter I Page

Introduction — Modern methods of steam and hot-water heating and ventilation — Evolution of steam and hot-water heating and ventilation — The practice of heati. g and ventilation — Steam ar.d hot-water heating and ventilation — A practical treatise — Steam and hot-water heating and ventilation and practia^ 15

Chapter II

Heat — Nature of heat — How measured — How transmitted — The heat unit

(B, T. U.) — Radiating power of bodies — Absorption of heat ... 18

Chapter III

Evolution of artificial heating apparatus — Open fire-places — Stoves — ^Furnaces — Average life and cost — Healthfulness — Early type of boilers — Steam boilers, Hot-water heaters

Chapter IV

Boiler surfaces and settings — Grate surface — ^Water surface — Boiler setting — The safety valve — ^The steam gauge — The automatic damper regulator — ^The water column and gauge glass — The blow-off cock — The firing tools and brushes — The fusible plug 40

Chapter V

The chimney flue — Sizes of chimneys — Elements of a good flue — Proper construction of chimney flues — Heights of chimneys — Table of heights and areas . 56

10 CONTENTS

Chapter VI

Pipe and fittings — Pipe — ^Table of sizes — Threading of pipe — Bending of pipe — Expansion of pipe — ^Table of pipe expansion — ^Wronght-iron or steel pipe — Nipples — Couplings — Fittings — Branch tees — Flanges — Table of flanges — Measuring pipe and fittings 63

Chapter XI

Steam-heating apparatus — ^The circuit system — ^The divided-circuit system — ^The one-pipe system — Dry returns — ^The overhead system — ^The two-pipe system — ^Advantages of steam heating — ^Tables — Sizes of mains . . . .103

Chapter XII

Exhaust-steam heating — Value of exhaust steam — Necessary fixtures— Heating

capacity of exhaust steam 115

Chapter XIII

Hot-water heating — Two-pipe system — Sizes of mains for two-pipe system — The expansion tank — Water connection — Table of expansion-tank sizes — The overhead system — Expansion-tank connections for overhead system — The circuit system — Sizes of mains for circuit system — Why water circulates . 120

CONTENTS 11

CHAPTEIl XIV

PAGE

Pressure systems of liot-water work — Table of temperatures — Expansion-tiink

connections for pressure work — Evans and Almirall systems .... 141

Chapter XV

Hot-water appliances — ^The altitude gauge — The hot-water thermometer — Floor and ceiling plates — Pressure appliances — The IIoneyAvell system — The Phelps heat retainer 146

Chapter XVI

Greenhouse heating — Early method — Modern greenhouse heating — Estimating radiation for greenhouses — Table of temperatures — ^IMethods of greenhouse piping 155

Chapter XVII

Vacuum vapor and vacuum exhaust heating — Explanation of a vacuum — Improved methods of exhaust heating — The Webster system — The Paul system — The Van x-Vuken system — Mercury seal systems — The K.M.C. system — The Trane system — The Ryan system — Vapor heating — The Broomell system — Vaciunn vapor heating — ^The Gorton system — The vacuum-vapor system — Dunham vacuo-vaj)or system — The future of vacuum heating . 163

Ventilation — ^Importance of ventilation — Air necessary for ventilation — ^Amount

of air required — Methods of ventilation 211

12 CONTENTS

Chapter XXI

Aiechanical ventilation and hot-blast heating — Growth and improvement — Methods employed — Exhaust and plenum — Heat losses and heating capacity required — Quality of the air supplied — An ideal system — Fans for blowing and exhausting. — Types of heaters — Methods of dri\dng fans — Some details of construction — Factory heating — Relative cost of installation and operation — ^^Vpparatus for testing 224

Chapter XXII

Steam appliances — Steam traps — Return traps — Separators — Oil separators — Steam separators — Feed-water heaters — Steam pumps — Boiler feed pumps- Vacuum pumps — Pump governors and regulators — Back-pressure valves — Pressure-reducing valves — Injectors — Inspirators — Automatic water feeders . 262

Chapter XXIII

District heating — Early methods — ^Modern methods — Central station hot-water

heating — Scale of hot-water temperatures 288

Chapter XXIV

Pipe and boiler covering — Importance of covering pipes — Saving effected by

covering — Materials used — Underground covering 293

Chapter XXV

Temperature regulation and heat control — Automatic steam damper regulator, automatic temperature regulators — The Pow-ers thermostat, the Powers system — The National regulator — The D. & R. regulator — The Howard regulator — The IVIinneapolis regulator — The Lawler thermostatic regulator — The Johnson pneumatic system ^ . . 299

Chapter XXVI

Business methods — Estimating — Proposal and bid — Specifications for steam heating — Specifications for hot-water heating — Special features of contracts . 316

CONTENTS 13

CIL\l»TEll XXVII

PAGE

Miscellaneous — Care of heating apparatus — Summer care — Proper attention to boilers — Removal of oil and dirt — Summer tests to determine efficiency — Care of tools — Labor-saving suggestions — Bronzing, jxiinting, and decoration — Guaranty — Boiler explosions — Prevention of boiler explosions — Utilizing waste heat 329

CHAPTER XXVm

Rules, Tables, and Useful Information 347

Introduction

It is well in beginning the study and consideration of the science of heating and ventilation to look back to the start of what has grown to be one of our most important industries.

We may properly term it Domestic Engineering, as on the work of the heating and ventilating engineer depends largely the health, and consequently the happiness, of the great body of civilized people of the world.

There is no doubt that the use of hot water for heating purposes antedates the use of steam. We have a more or less obscure record of the use of hot water in this respect by the Romans. In the beginning of the eighteenth century we have records of greenhouses (at that time called " hothouses ") being successfully heated by hot water and later in the same century, about the year 1775, we find a Frenchman, Bonnemain, using hot water to heat a brooder on a chicken farm. This may be said to be the beginning of the practical application of hot water for heating purposes.

Steam was probably first used for heating purposes in the early part of the nineteenth century, when efforts were made to heat a factory by steam at a high pressure. The development of steam heating from that date to the present time has been both rapid and constant, although the last decade has seen this industry advanced to a state of perfection never dreamed of by the early heating engineers. From a loose and haphazard method of figuring and installing work of this character, it has reached a scientific stage, and as such is more or less understood by a large majority of those engaged in the business.

Heating and Ventilation are kindred trades and sciences, each, in a measure, dependent on the other. The early effort to ventilate the British House of Commons, in 1723, was probably the real beginning of artificial ventilation.

Dr. J. F. Desaguliers, a French boy, whose father removed to England when Desaguliers was but an infant, was, without doubt, the most distinguished student of physics and mechanics of that time. To him was intrusted the problem of ventilating the House of Commons. Previous to this date, however, other plans had been tried to provide a means of ventilation, but we believe the first scientific study and experiments were conducted by Dr. Desaguliers.

Efforts were put forth during the early part of the nineteenth centurj^ to improve on this ventilating apparatus by the providing of large fans or blowers, which were propelled by hand. The ventilation of other public buildings was then undertaken and the science had advanced to such a stage that in the year 1824 an English engineer, Tredgold by name, published a book entitled " Principles of Warming and Ventilating Public Buildings " — a standard work still referred to at this date.

While the history of the sciences of heating and ventilation and the endeavors of many engineers of eminence may be both interesting as well as instructive, we refer only to the beginning in order that our readers may realize, to the fullest extent, the evolution of the methods of heating by steam and hot water and ventilating by natural or mechanical means.

To such men as Tredgold, Dr. Reid, Charles Hood, E. Peclet, Robert Briggs and others of earlier date, and Mills, Billings, Baldwin, Carpenter and other engineers of these latter times, are we indebted for the advancement and perfecting of the various methods of estimating and constructing the warming and ventilating systems of to-day.

The remainder of the credit is justly due to those who manufacture and install the work and who have, by the use of modern machinery and up-to-date ideas, reduced the cost of steam and hot-water warming and ventilating apparatus to such an extent as to place it within the reach of those in moderate circumstances.

Our public schools are better warmed and ventilated than ever

INTRODUCTION 17

before, as are also tlic majority of our other public and semi-public buildings. Our architects now study and consider the subject of heating and ventilation and we firmly believe that the coming decade will witness far greater advancement in these sciences than we have known before.

An estimate made in the year 1906 shows that but a little over one tenth of our homes and public buildings are provided witli steam or hot-water heating apparatus. Such an estimate further reveals the fact that less than two per cent of our homes arc provided with even a partial ventilating apparatus.

As a nation we seem to have been satisfied to roast one side of our body while the other side was chilled, or, when fresh air was absolutely needed in the room, to open the door or window, regardless of the outside temperature or the condition of the weather. These sudden changes, of course, produced colds and bodily ills of like nature, which, no doubt, in many cases, proved fatal. We knew of no uniformity in either the temperature of the house or the purity of the atmosphere in the several rooms.

Becoming aware of our mistakes of the past, we now" demand a uniform temperature within our homes ; we are swiftly coming to the conclusion that we might better pay the coal dealer for the energy to produce heat, ventilation and comfort than to pay our physician for doctoring the ills resulting from our carelessness.

It will be readily noted what a tremendous field there is for study and work along these lines, and to the journeyman steam fitter or contractor who fits himself thoroughly for this work, we see an abundant reward In store.

CHAPTER II Heat

Heat is motion, or a form of energy. Scientists tell us that it is their belief that all matter is made up of small A^brating particles called molecules. The faster these particles move or vibrate, the more heat is produced, and the more the matter or body is expanded. This expansion may be carried to such an extent as to transform the body into another state. For example, note the formation of gas from coal or oil, or the formation of steam from water.

With a hammer we may pound upon a piece of iron until it becomes hot. The Indians started a fire by briskly rubbing together two pieces of wood, the energy of motion producing the necessary heat to ignite the dry moss, or other material used for kindling.

The nature of heat is peculiar and it is w^ell that we become somewhat acquainted with these peculiarities.

Heat cannot be measured as to quantity, but the intensity of heat may be measured by a thermometer, and this measure we call temperature, and for registering this temperature we use the Fahrenheit scale. For example, water freezes at 32° F. and boils at 212° F. (Fahrenheit was a German, who in 1721 made the first mercurial thermometer. )

Heat may be transferred from one body to another by three distinct methods, namely. Conduction, Convection and Radiation. Lay a piece of hot iron upon another piece of iron, or a different object, and a certain proportion of the heat from the heated iron is transferred to the under object. This method is by Conduction.

Water which has been heated and transferred to a storage tank through pipes makes the tank hot. This is heating by Convection.

We may place a chair too near a heated stove and burn or blister the paint or finish upon same. The chair has not been

HEAT 19

against the stove, neither has there been any direct connection between it and the heat producer, yet it has received the heat from the stove to such an intensity as to damage it. This damage was caused by radiation of heat, the heat being carried to the chair upon waves of air usually imperceptible to the eye.

It is this latter method of heat transfer which is employed in the warming of buildings. The energy is developed at a boiler, or heater, placed usually in the basement of the building, the heat being transferred to the radiators, or radiating surfaces placed within or adjacent to the room to be heated and the heat again trans-ferred to the room by radiation.

While we cannot properly measure heat itself, we may measure it by the effect it produces, and this is accomplished by the so-called Heat Unit. The Heat Unit as adopted for engineering and scientific purposes is of three measures : viz., British, French and German. In this country it is the former that has come into general use.

A British Thermal Heat Unit (B. T. U.) is the amount of heat required to raise the temperature of a pound of water one degree Fahrenheit, or one degree on the Fahrenheit scale of measuring. The British system of measuring heating work, or the effect produced by the action of heat, is by what is known as foot pounds. Professor Allen's definition of this term foot pounds is as simple as we have come across. He says : " Ten units of work or ten foot pounds would be the amount of w'ork done in raising ten pounds one foot high, or one pound ten feet high." Professor Allen thus calls our attention to the definite relationship between heat and work, which was probably first determined by Joule in 1838 while conducting a series of experiments.

In measuring w^ork the term horse power (H. P.) is frequently made use of. A horse power is 33,000 foot pounds per minute, or the amount of work required to raise 33,000 pounds one foot high per minute, and this is equivalent to 42.5 heat units per minute.

As in this country the capacity of all engines and machinery, and all tubular and power boilers, is expressed by horse power, it IS well to remember that a horse power represents the energy developed by evaporating 2.655 pounds of water into steam, and which is sufficient to supply 100 square feet of radiation. Furthermore, a horse power represents the condensation from 100 square feet of direct cast-iron radiation, or approximately 90 square feet of pipe radiation or heating coils.

The steam is condensed by loss of heat or cooling, and we must know in what manner certain elements act upon the heating surface to cool it, and again in what manner the heat is given off from the radiator or heated body.

All building material is porous and there is a loss of heat through walls and window glass. Again, a ventilating register may be open in the room. There is a constant loss of heat through this aperture until such time as it is closed. Therefore, to determine upon the amount of heat necessary we must take into consideration all heat losses and this we shall discuss later on in this work.

Heat is radiated in straight lines or in waves from a heated body. If certain objects are placed in the line of these waves they will absorb the heat and transmit it again to some cooler body. On the contrary, such substances as magnesia, asbestos, hair felt, and the like, will prevent the radiation of the heat beyond their influence. For example, note the plastic covering on boilers, or the asbestos and hair-felt coverings placed on steam and hot-water pipes. Air and other gases are almost transparent to heat and, in fact, in many cases assist in conveying it from the source of energy to the body to be warmed.

The radiating power of bodies differs materially. Polished or enameled surfaces radiate less heat than rough or unfinished surfaces. Peclet gives the following table of the radiating power of bodies, the figures equaling heat units given off from a square foot of surface per hour for a difference of one degree Fahrenheit :

TABLE NO. I

Radiating Power of Bodies

Polished Copper 0327

Sheet Iron 0920

Glass 5940

Cast Iron (rusted) 6480

Stone, Wood or Brick 7358

Woolen Material 7522

HEAT n

A cast-iron radiator will radiate much less heat when enameled than when painted with bronze or a mineral paint.

Specific heat is the amount of heat necessary to raise the temperature of a solid or liquid bod3' a certain iiunil)er of degrees, taking water as a unit or standard of c()ni})aris()n.

Some bodies absorb heat more rapidly than others. According to Walter Jones, M.E., the heat necessary to raise one pound of water one degree will raise

32 lbs. of Lead

31 lbs. of Mercury

9 lbs. of Iron \ one degree.

4I/2 lbs. of Air

or 2 lbs. of Ice

For the practical purposes of the steam fitter it is necessary only that he consider:

1. The energy necessary to produce a certain amount of heat, or number of heat units ; how produced, and how measured.

2. How these heat units may be transferred, radiated or conducted from one body to another.

3. The effect of this heat upon the cooler body to which it is transferred, or the so-called cooling surfaces of a room or building.

4. The percentage of loss of energy by radiation, or otherwise, between the production of the heat and its delivery to the body to be warmed.

In the discussion of radiation, ventilation, etc., w^e shall give other peculiarities and facts regarding the loss of heat, the causes leading to the same and rules for providing against the amount of heat loss under varying conditions.

CHAPTER III Evolution of Artificial Heating Apparatus

The arrangement of some form or method of securing warmth within our homes or buildings is a matter to which our attention has grown in keeping with our advancement as a nation.

History relates that among the ancient Romans it was customary for the poorer class to build fires upon a stone or brick floor located at one side or end of a room, the smoke and soot passing out of the room through holes in the roof. The wealthier class used braziers in their living rooms, in which was burned carefully dried wood.

The heating apparatus of our forefathers was the open fireplace, and it is related of the old New England type of fireplace that it was six or eight feet in length and so deep that the children had blocks on which they sat far within, where they could see the stars up the chimney. Large logs of wood were used for fuel. Later, after coal could be purchased, the fireplace was built very much smaller.

In either case a very large proportion of the heat thus obtained escaped up the chimney, probably from seventy-five to ninety per cent being lost in this manner.

As the country grew in population, cities and towns sprang up and fuel became scarcer. Larger buildings were erected and the number of rooms increased until, as a matter of economy, it became necessary to provide some other form of heating apparatus.

To this end the old Franklin stove was designed, followed by later styles more improved, all in order to provide better combustion and save the lost heat.

Again was " necessity the mother of invention," as, to save labor of carrying fuel and ashes for many fires, the idea of centralizing the heating apparatus and of warming several rooms from one fire, led to the adoption of the inclosed stove. Tin or sheet-iron pipes were used to convey the heated air to each separate room and from this arrangement deveh)pcd tlie modern furnace.

Kx])eriments were next conchicted witli lieated water and steam as means of conveying heat from a central point to various parts 01 a huilding, a form of heating wliich has been carried to sucli a state of perfection as to warrant the use of either system under ahnost any known conchtion, and tlie estabhsliing of founch'les and shops for the manufacture of heating apparatus. The devek)pment has been such that at the present time there are man^^ milHons of dollars invested in the business of manufacturing and installing apparatus for heating by steam and hot water.

The relative efficiency of the several methods of heating may be given as follows :

1. Open Fireplaces.

2. Stoves.

3. Hot-Air Furnaces.

4. Steam.

5. Hot Water.

In classifying them in this order, we consider not only efficiency, but health fulness, durability, and cost of maintenance, i. e., cost for fuel.

Were healthfulness alone considered, we should prefer the open fireplace to either stoves or furnaces. The waste of fuel in fireplaces and stoves, largely also in hot-air furnaces, is too well known to need many comments.

Fireplaces radiate the heat from one side of the room only, and stoves warm but in spots.

Furnaces fail to produce the right results when placed in buildings not well protected from the wind; and there is no uniformity in temperature where any one of the three above-mentioned systems are used.

Furnaces as ordinarily installed are not much more satisfactory than stoves, and nine tenths of them are too small. They are used in preference to a steam or hot-water apparatus because of the apparent saving in cost. We say apparent saving in cost, as after all things are weighed, there is no saving in using a furnace in preference to steam cr h.ot water, and it is well that the steam fitter or lieating contractor hiis this fact clearly in mind. Therefore, we shall discuss this feature of furnace heating very freely and shall consider the matter, endeavoring to show a comparison between the furnace and steam or hot-water heat.

First: As to cost and average life of the apparatus.

Second: As to comfort and healthfulness.

Average Life and Cost

Where a furnace too small is installed, it is necessary, in extreme cold weather, to raise the heating surfaces to an exceedingly high temperature, often a red heat, in order to secure comfort. As a result, the expansion and contraction loosens the joints of the furnace and allows the sulphurous and carbonic-oxide gases and other poisonous products of combustion to escape through the hot-air pipes into the rooms above. This is true of both wrought-iron and cast-iron furnaces.

Again, heating the furnace to this extremely high temperature shortens the life of the apparatus, with the result that ten per cent of the first cost is needed for repairs during the first five years, while, as a rule, the next five years find the furnace entirely worn out.

A steam-heating apparatus has an average life of probably twenty-five years, the first ten years of this period without any repairs except of a trivial nature, such as the repacking of valves, etc.

A hot-water-heating apparatus will last an even greater length of time, without the expense of repairs, the system being practically indestructible. Thus it will be readily seen that while the cost of a furnace, as usually installed, is but one half that of a steam-heating apparatus, or probably two fifths that of a hot-water-heating apparatus, it is, as an investment, not counting healthfulness or the excess amount of fuel consumed, by far the more costly of the three systems.

In pondering the question of cost, we have not taken into consideration the long list of fires and damaged buildings resulting from the " defective flue," nor the damage to house furnishings, due to dust and dirt from the furnace. The housewife, more than anyone else, knows of the constant dusting and cleaning and the frequency with which it is necessary to renew carpets and draperies.

Healthfulness of Furnace Heating ^s. Steam or Hot Water

We have mentioned some of the disadvantages of heating with a furnace. Let us now consider the healthfulness of the various systems, the quality of the heat produced and its effect on the human system.

A furnace must of necessity have an air supply. The source of this air supply is often very bad. Perhaps the air is admitted to the furnace direct from the basement or cellar in which it is located. This air may be contaminated with the odors from decaying vegetable matter, or gases from a sewer. The air is admitted to the furnace at its base, or from underneath the base, and when a fresh air supply is taken from outside the building, it is frequently conveyed to the furnace through an underground duct which is not air tight, with the result that it gathers impurities from the earth. The duct may run across the basement floor and if not air tight, will, owing to the draught produced by the furnace, suck in the impure air from the basement through the numerous cracks or crevices. With an impure air supply, it is impossible to serve the occupants of the building with pure air. Again, the air is devitalized by passing over metal, heated often to 1,200 or 1,500 degrees Fahr., which robs it of all its health-giving properties.

The advocate of the furnace will endeavor to tell of the pure air which is constantly admitted to the building, and its advantages — an exploded theory, as every heating and ventilating engineer knows.

What then with devitalized air, often charged with dust or poisoned by gases, can we say in favor of the healthfulness of heating with a hot-air furnace.^ Nothing, except possibly the apparent saving in first cost and the freedom of the house owner from participating In the " semiannual stovepipe performance," viz. — that of taking down or putting up a miscellaneous assortment of stovepipe loaded with soot, as would be the case where stoves were used.

Heating by either steam or hot water has none of the disadvantages mentioned and for this reason, since the large reduction in cost during the last decade, have in their several forms and variations, been generally adopted as the best methods of heating known.

There are many buildings more or less protected from the variable winds of winter, where a furnace properly installed will heat all parts of the building to a uniformly comfortable temperature. We emphasize " properly installed " and " all parts " for the reason that the average furnace has neither of these conditions to recommend it. As a rule, the contractor setting the furnace places it near to the center of the basement in order to shorten the hot-air supply pipes and thereby simplify or cheapen the work. It is impossible to force the heated air to the side of the building against which the wind is blowing, and for this reason the furnace should be set near to the side which most frequently receives the action of the wind. We think it safe to say that a furnace installed in this manner and built heavy enough to last a considerable term of years, with the tin work of first quality, will cost one third more than the average furnace job as regularly installed, or to within a very small amount of the price of a low-pressure steam-heating apparatus.