This series is an introduction to the basic principles of heating , ventilating and air conditioning. Each of these represents a sys tematic attempt to control the various aspects of tne environment within an enclosure whether it be a room, a group of rooms, or a building.
Among those aspects of the immediate environment that man first sought to control were heat and ventilation. Attempts at con trolling heat date from prehistoric times and probably first devel oped in colder climates where it was found necessary to produce temperatures sufficient for both comfort and health. Over the years the technology of heating advanced from simple attempts to keep the body warm to the very sophisticated systems of maintaining stabilized environments in order to reduce heat loss from the body or the structural surfaces of the room.
Ventilation (covered in Volume 3) also dates back to very early periods in history. Certainly the use of slaves to wave large fans or fan-like devices over the heads of rulers was a crude early attempt to solve a ventilating problem. Situating a room or a building so that it took advantage of prevailing breezes and winds was a more sophisticated attempt. However, it was not until the nineteenth century that any really significant advances were made in ventilat ing. During that period, particularly in the early stages of the Industrial Revolution, ventilating acquired increasing importance. Work efficiency and the health of the workers necessitated the creation of ventilation systems to remove contaminants from the air. Eventually, the inter relationship of heating and ventilating became such that it is now regarded as a single subject.
Air conditioning (Volume 3) is a very recent development and encompasses all aspects of environmental control. In addition to the control of temperature, both humidity (i.e. the moisture con tent of the air) and air cleanliness are also regulated by air con ditioning. The earliest attempts at air conditioning involved the placing of wet cloths over air passages (window openings, en trances, etc.) to cool the air. Developments in air conditioning technology did not progress much further than this until the nine teenth century. From about 1840 on, several systems were devised for both cooling and humidifying rooms. These were first developed by textile manufacturers in order to reduce the static electricity in the air. Later, adaptations were made by other industries.
Developments in air conditioning technology increased rapidly in the first four decades of the nineteenth century, but widespread use of air conditioning in buildings is a phenomenom of the post World War II period (i.e. 1945 to the present). Today, air condi tioning is found not only in commercial and industrial buildings, but in residential dwellings as well. Unlike the early forms of air conditioning which were designed to cool the air or add moisture to it , modern air conditioning systems can control temperature , air moisture content , air cleanliness, and air movement. The modern systems condition the air, rather than simply cool it.
HEATING AND VENTILATING SYSTEMS
Many different methods have been devised for heating buildings. Each has its own characteristics and most of them have at least one objectionable aspect (e.g. high cost of fuel, expensive equipment, or inefficient heating characteristics). Most of these heating methods can be classified according to one of the following four criteria:
1. The heat conveying medium,
2. The fuel used,
3. The nature of the heat,
4. The efficiency and desirability of the method.
The term “heat conveying medium” means the substance or combination of substances that carries the heat from its point of origin to the area being heated. There are basically four mediums for conveying heat. These four mediums are:
1. Air,
2. Water,
3. Steam,
4. Electricity.
Different types of wood, coal, oil, and gas have been used as fuels for producing heat. Electricity may be considered both as a fuel and a heat conveying medium. Each type of heating fuel has its own characteristics and the advantages of one over another depends upon such variables as availability , the efficiency of the heating equipment (which in turn is dependent upon design, main tenance, and other factors), and cost. A detailed analysis of the use and effectiveness of the various heating fuels is found in Chapter 5 (HEATING FUELS)
Heating methods can also be classified with respect to the nature of the heat applied. For example, the heat may be of the exhaust steam variety or it may consist of exhaust gases from internal com bustion engines. The nature of the heat applied is inherent to the heating system itself and can be determined by reading the various chapters that deal with each type of heating system (Chapters
6 thru 9) or with heat producing equipment (e.g. Chapter 11:GAS-FIRED FURNACES).
The various heating methods will differ considerably in efficiency and desirability. This is due to a number of different but often interrelated factors such as fuel cost, conveying medium employed and the type of heating unit. The integration of these interrelated components into a single operating unit is referred to as a heating system.
There are a great variety of heating systems due to the different conditions met with in practice, but most fall into one of the fol lowing broad classifications:
1. Warm-air heating system (Chapter 6),
2. Hot-water heating systems (Chapter 7),
3. Steam heating systems (Chapter 8),
4. Electric heating systems (Chapter 9).
You will note that these classifications of heating systems are based on the heat conveying method used. This is a convenient method of classification because it includes the vast majority of heating systems used today.
As was previously mentioned, ventilating is so closely inter related with heating in its various applications that the two are very frequently approached on the basis of being a single subject. However, specific aspects of ventilating are considered in Chapter 6 (VENTILATION PRINCIPLES); and Chapter 7 (FAN SE LECTION AND OPERATION) in Volume 3.
The type and design of ventilating system employed will depend upon a number of different factors, including:
1. Building use or ventilating purpose ,
2. Size of building ,
3. Geographical location,
4. Heating system used.
A building used as a residence will have a different ventilating system from one used for commercial or industrial purposes. More over, the requirements of a ventilating system used to provide fresh air as opposed to one that must remove noxious gases or other dangerous contaminants from the enclosure results in fundamental design differences.
The size of a building is a factor that must also be considered.
A large building with internal areas far from the points where out side air would initially gain access will produce certain ventilating problems. These can usually be solved by giving special attention to the overall design of the ventilating system.
Buildings located in the tropics or semi-tropics present different ventilating problems from those found in the temperate zones. The differences are so great that they often result in different architectural forms. At least this was the case before the advent of widespread use of air conditioning. The typical southern house of the nineteenth century was constructed with high ceilings (heat tends to rise), large porches which sheltered sections of the house from the hot, direct rays of the sun, and large window areas to admit the maximum amount of air. They were also usually situated so that halls, major doors and sleeping areas faced the direction of the prevailing winds. Today, with air conditioning so widely
used, these considerations are not as important -at least not until the power fails or the equipment breaks down.
AIR CONDITIONING
Although the major emphasis in this series has been placed on the various aspects of heating and ventilating, some attention has also been given to air conditioning. The reason for this, of course, is the increasing use of year-round air conditioning systems that provide heating, ventilating, and cooling. These systems condition the air by controlling its temperature (warming or cooling it),
cleanliness, moisture content, and movement. This is the true meaning of the term “air conditioning.” Unfortunately , it has be come almost synonymous with the idea of cooling, and this is becoming increasingly misrepresentative of the true function of an air conditioning system. Air conditioning, particularly the year round air conditioning systems are examined in detail in Chapters 8, _9 and 10 of Volume 3.
SELECTING A SUITABLE HEATING, VENTILATING, OR AIR CONDITIONING SYSTEM
There are a number of different types of heating, ventilating, and air conditioning equipment and systems available for the installa tion in the home. The problem is choosing the most efficient one in terms of the installation and operating costs. These factors are, in turn, directly related to one’s particular heating and cooling requirements. The system must be the correct size for the home. Any reputable building contractor or heating and air conditioning firm should be able to advise you in this matter.
If you are having a heating and ventilating or air conditioning system installed in an older house, be sure to check the construc tion. Weather stripping is the easiest place to start. All doors and windows should be weatherstripped to prevent heat loss. Adequate weatherstripping can cut heating costs by as much as 15 to 20%. If the windows provide suitable protection (they should be double or triple-glazed) from the winter cold, check the calking around the edge of the glass. If it is cracking or crumbling, replace it with fresh calking. You may even want to go to the expense of insulating
the ceilings and outside walls. This is where a great deal of heat loss and air leakage occur.
You have several advantages when you are building your own house. For example, you may be able to determine the location of your house on the lot. This should enable you to establish the direction in which the main rooms and largest windows face. If you position your house so that these rooms and windows face south, you will gain maximum sunlight and heat from the sun during the cold winter months. This will reduce the heat requirement and heating costs. The quality of construction depends on how much
Table 1. The relationship between career category and the type or degree of education
and/ or t raining required for it.
| Career Category | Type Of Work | Education/Training |
| Engineer | Design and Development | 4 Yrs. or More of College |
| Technician | Practical Application | Technical Training School and/or College |
| Skilled Worker | Installation, Maintenance, Repair | Apprentice Program or On-The-Job (OJT) Training |
| Apprentice or OJT Worker | Training for Skilled Worker Position | High School Degree or Equivalency Usually Required |
you wish to spend and the reliability of the contractor. My advice would be to purchase the best insulation you can afford. Your reduced heating costs will eventually pay for the added cost of the insulation. If you suspect that your building contractor cannot be trusted, you can reduce opportunities for cheating and careless work by making frequent and unexpected visits to the construction site.
CAREER OPPORTUNITIES
Ther are many career opportunities available to the individual in heating, ventilating, air conditioning and related fields, and they extend over several levels of education and training. Accordingly, the career opportunities open to an individual seeking employment
in these fields can roughly be divided into four categories , each dependent upon a different type or degree of education and/ or training. This relationship is shown in Table 1.
Engineers are usually employed by laboratories, universities and colleges, or frequently by the manufacturers of materials and equip ment used in heating, ventilating, air conditioning and related industries. They receive the highest pay , but also undergo the long est periods of education and training. Their primary responsibility is designing, developing and testing the equipment and materials used in these fields. In some cases. particularly where large build ings or district heating to several buildings is employed , they also supervise the installation of the entire system. Furthermore, industry codes and standards are usually the results of research conducted by engineers.
Technicians obtain their skills through technical training schools. some college, or both. Many assist engineers in the practical appli cation of what the latter have designed. They are particularly necessary during the developmental stages. Other technicians are found in the field working for contractors in the larger companies. Their pay often approximates that of engineers , depending on the size of the company for which they work.
Skilled workers are involved in the installation, maintenance and repair of heating, ventilating, and air conditioning equipment. Apprentices and OJT workers are in training for these skilled posi tions, and are generally expected to complete at least a 2 to 5 year training program. Most skilled workers and trainees are employed by local firms that install or repair equipment in resi dential, commercial, and industrial buildings. Some also work on the assembly lines of factories that manufacture such equipment. Their pay varies depending on the area, seniority, and the nature of the work. Most employers require that both the skilled workers and trainees have at least a high school diploma or its equivalent
(e.g. the G .E.D.). The requirement for a high school diploma may be waived if the individual has already acquired the necessary skills on a previous job. The pay is lower than that earned by engineers and technicians, but compares favorably to salaries received by skilled workers or equivalent training in other occupations.
Pipefitters, plumbers, steamfitters. and sheetmetal workers all may occasionally do some work with heating, ventilating and air conditioning equipment. Both pipefitters and plumbers (especially the former) are frequently called upon to assemble and install pipes and pipe systems that carry the heating or cooling conveying medium from the source. Both are also involved in repair work, and some pipefitters can install heating and air conditioning units.
Steamfitters can assemble and install hot-water or steam heating systems. The installation of boilers, stokers, oil and gas burners, radiators, radiant heating systems, and air conditioning systems can also be done by many steamfitters.
Sheetmetal workers can also assemble and install heating, ventilating, and air conditioning systems. Their skills are particularly necessary when assembling sheet metal ducts and duct systems.
Some specialty occupations such as those performed by air con ditioning and refrigeration mechanics or stationary engineers are limited to certain functions in the heating, ventilating and air condi tioning fields. The former is primarily involved with assembling, installing and maintaining both air conditioning and refrigeration equipment. Stationary engineers, on the other hand, maintain and operate heating , ventilating , and air conditioning equipment in large buildings and factories. Workers in both these occupations require greater skills and longer training periods than most skilled workers.
It should be readily apparent by now that the heating, ventilat ing and air conditioning fields offer a variety of different career op portunities. The pay is generally good and the nature of the work provides considerable job security. Both the type of work and the level at which it is done depends solely on the amount and type of education and training acquired by the individual.
PROFESSIONAL ORGANIZATIONS
A number of professional organizations have been established for those who work in the heating, ventilating and air conditioning industries, or who handle their products. These organizations (frequently referred to as associations, societies, or institutes) pro vide a number of different services to both members and non members alike, including:
1. The compilation of safety codes and other standards,
2. Educational programs rmd training schools,
INTRODUCTION
3. Market research and various technical services
4. The compilation of industry-wide statistics,
5. The dissemination of information in the form of journals: books, pamphlets, movies, slides, and tapes.
Some of these professional organizations have established permanent libraries as resource centers for those seeking to improve their skills or who wish to keep abreast of current developments in their fields. In many instances, research programs are conducted in cooperation with laboratories: colleges, and universities.
Anyone, member or not, can write to these professional organiza tions for information or assistance. Most of them seem very willing to comply with any reasonable request. The only difficulty that may be encountered is determining the current name of the particular organization and obtaining its address. Unfortunately, these pro fessional organizations have shown a strong proclivity towards mergers over the years with resulting changes of names and addresses.
The best and most current guide to the names and addresses of professional organizations is The Encyclopaedia of Associations which can be found in the reference department of most public libraries. It is published in three volumes, but everything you will need can be found in the first one. At the very back of this volume is a section called the “Alphabetical & Key Word Index.” By look ing up the key word (e.g. “heating” or “ventilating”) of the subject that interests you-you will find the page number and full name of the professional organization (or organizations) concerned with this particular area.
There are over twenty different professional organizations in the United States concerned with heating, ventilating, air conditioning or related fields (e.g. fuels, piping, etc.). Many of them address themselves to the problems and interests of specific groups. For example, there are professional organizations for manufacturers, wholesalers, jobbers, distributors, and journeymen. Some organiza tions represent an entire industry, while others restrict their scope to only a segment of it. Every aspect of heating, ventilating, and air conditioning is covered by one or more of these professional organizations.
Among the more than twenty professional organizations currently active are the following:
1. Air-Conditioning and Refrigeration Institute (ARI).
2. Air-Conditioning and Refrigeration Wholesalers (ARW).
3. Air Moving and Conditioning Association (AMCA).
4. Air Diffusion Council (ADC).
5. American Gas Association (AGA).
6. American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE).
7. American Society of Mechanical Engineers (ASME).
8. Association of Industry Manufacturers (Plumbing- Heating -Cooling -Piping).
9. Electric Energy Association (EEA).
10. Hydronics Institute.
11. International Solar Energy Society.
12. Mechanical Contractors Association of America (MCAA).
13. National Association of Oil Heating Service Managers (NAOHSM).
14. National Association of Plumbing-Heating-Cooling Contractors.
15. National Environmental Systems Contractors Association (NESCA).
16. National LP-Gas Association (NLPGA).
17. National Oil Fuel Institute (NOFI).
18. National Warm Air Heating and Air Conditioning Associ- ation (NWAH & ACA).
19. Plumbing-Heating-Cooling Information Bureau (PHCIB).
20. Refrigeration Service Engineers Society (RSES).
21. Sheet Metal and Air Conditioning Contractors’ National Association (SMACNA).
Some professional organizations of long standing have been merged with others or have been disbanded. For example, the Steel Boiler Institute (formerly the Steel Heating Boiler Institute) which maintained standards in the heating industry with its SBI Rating Code is now defunct. The Institute of Boiler and Radiator Manufacturers (source of the old IBR Code) merged with the Bet ter Heating-Cooling Council to form the Hydronics Institute. Arecent attempt to contact the Steam Heating Equipment Manu facturers Association has resulted in the return of a letter marked ..no forwarding address.” It seems very likely that it, too has joined the list of defunct professional organizations.
Appendix A (PROFESSIONAL AND TRADE ASSOCIATIONS) at the end of this book gives a listing of these professional organizations. It also contains their present address, the names of some of their publications, and a brief synopsis of their background and whom they represent.