In the foregoing sections of this Cyclopedia numerous illustrative examples are worked out in detail in order to show the application of the various methods and principles. Accompanying these are examples for practice which will aid the reader in fixing the principles in mind.

In the following pages are given a large number of test questions and problems which afford a valuable means of testing the reader's knowledge of the subjects treated. They will be found excellent practice for those preparing for College, Civil Service, or Engineer's License. In some cases numerical answers are given as a further aid in this work.

## Review Questions On The Subject Of Heating And Ventilation. Part I

1. What advantage does indirect steam heating have over direct heating? What advantages over furnace heating?

2. What are the causes of heat loss from the building?

3. Why is hot water especially adapted to the warming v,i dwellings?

4. What proportion of carbonic-acid gas is found in out door air under ordinary conditions?

5. A room in the N. E. corner of a building is 18' square and 10' high; there are 5 single windows, each 3' X 10' in size; the walls are of brick 12" in thickness. With an inside temperature of 70 degrees, what will be the heat loss per hour in zero weather? Ans. 21,447 B. T. U.

6. State four important points to be noted in the care of a furnace.

7. A grammar school building has 4 rooms, one in each corner, each being 30' X 30' and 14' high and seating 50 pupils. The walls are of wooden construction, and the windows make up 1/3 of the total exposed surface. The basement and attic are warm. How many pounds of coal will be required per hour for both heating and ventilation in zero weather, if 8,000 B. T. U. are utilized from each pound of coal? Ans. 96.3 lbs.

8. What two distinct types of furnaces are used? What are the distinguishing features?

9. What is meant by the efficiency of a furnace ? What efficiencies are obtained in ordinary practice?

10. What are the principal parts of a furnace? State briefly the use of each.

The walls are 12" in thickness and 1/4 the total exposed wall is taken up by windows, which are double. The basement is warm, but the attic is cold. The house is to be warmed to 70 degrees when it is ten degrees below zero outside. How many square feet of grate surface will be required, assuming usual efficiencies of coal and furnace? Ans. 8.5 square feet.

12. A high school is to be provided with tubular boilers. What H. P. will be required for warming and ventilation in zero weather if there are 600 occupants, and the heat loss through walls and windows is 1,500,000 B. T. U. per hour?

Ans. 114.8

13. What are the three essential parts of any heating system?

14. Is direct steam heating adapted to the warming of schoolhouses and hospitals? Give the reasons for your answer.

15. The heat loss from a dwelling house is 280,000 B. T. U. per hour. It is to be heated with direct steam by a type of boiler in which the ratio of heating surface to grate surface is 28. What will be the most efficient rate of combustion, and how many square feet of grate surface will be required?

Ans. 7 pounds. 5 sq. feet.

16. What is the use of a blow-off tank? Show by a sketch how the connections are made.

17. How are the sizes of single pipe risers computed?

18. What weight of steam will be discharged per min. through a 6" pipe 300' long with an initial pressure of 10 pounds and a drop of 3/4 pound in its entire length?

19. What is an air valve? Upon what principles does it work?

20. What size of steam pipe will be required to discharge 2400 pounds of steam per hour a distance of 900', with an initial pressure of sixty pounds and a drop in pressure of 5 pounds?

Ans. 3 1/2 dia.

21. What objection is there to a single pipe riser system? How is this sometimes overcome in large buildings?

22. What patterns of valves should be used for radiators? What conditions of construction must be observed in making the connections between the radiator and riser?

23. The heat loss from a shop is 36,000 B.T.U. per hour; how many linear feet of 2" pipe will be required to warm it, using low pressure steam? Ans. 192 feet.

24. What are meant by "wet" and "dry" returns? Which is the better, and why ?

25. How many linear feet of 1 1/4" pipe are required to give off the same amount of heat as a cast iron radiator having 125 square feet of surface? Ans. 215 feet.

26. What three systems of piping are commonly used in direct steam heating? Describe each briefly.

27. What is a "branch coil?" What is a "trombone coil?" In what cases would you use a trombone coil instead of a branch coil ?

28. What is meant by the efficiency of a radiator? Give average efficiencies of cast iron and pipe radiators, also circulation coil.

29. The heat loss from a room is 22,500 B.T.U. in zero weather. What size of cast iron radiator would be required to warm the room when it is twenty degrees below zero?

Ans. 128 square feet.

30. Where would you place the direct radiation in a schoolroom?

## Review Questions On The Subject Of Heating And Ventilation. Part II

1. How would you obtain the sizes of the cold and warm air pipes connecting with indirect heaters in dwelling-house work?

2. What is an aspirating coil and what is its use?

3. What efficiencies may be allowed for indirect heaters in schoolhouse work? How would you compute the size of an indirect heater for a room in a dwelling house?

4. How is the size of a direct-indirect radiator computed?

5. A schoolroom on the fourth floor is to be supplied with . 2,400 cubic feet of air per minute. What should be the area of the warm-air supply flue?

Ans. 6 square feet.

6. What is the chief objection to a mixing damper, and how may this be overcome?

7. How many square feet of indirect radiation will be required to warm and ventilate a schoolroom when it is 10 degrees below zero, if the heat loss through walls and windows is 42,000 B. T. U. and the air supply 120,000 cubic feet per hour?

Ans. 349 square feet.

8. What is the difference in construction between a steam radiator and one designed for hot water? Can the steam radiator be used for hot water? State reasons for answer.

9. How may the piping in a hot water system be arranged so that no air valves will be required on the radiators?

10. What efficiency is commonly obtained from a direct hot water radiator? How is this computed?

11. How should the pipes be graded in making the connections with indirect hot water heaters? Where should the air valve be placed?