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This thesis was contributed by
Mr. E. Ce Pokorny
under the date indicated by the depart-

ment stamp, to replace the original which
was destroyed in the fire of Mar. 5, 1916.

A design for a Heating and Ventilating system
for the new Engineering Bullding at the Michigan

ae

Agricultural College.

E. C. Pokorny.

GUase 1o'l.
 

THESIS

 
A design for a Heating and Ventilating system for the
new Engineering Building at the Michigan Agricultural College.

In designing a heating system, there are several things
which must be taken into consideration, such as the size of the
bullding, its location and its distance from the power plant.
= BUILDING =

The building in which the sustem is to be installed is
rectangular im shape, 184 feet long and 84 feet wide. It is five
stories high, the first story of stone and the other stories of
brick... (These measurements do not include the laboratory in the
rear of the building.) The building is partly protected on the
east side by the old Mechanical Building and on the west side by
Wells hall. The building has a north and south exposure.

= KIND of SYSTEM =

As there are several different systems of heating build-
ings or the campus, it was possible to determine the efficiency
of each system and make a comparison of same. From these results
as a basis to: work from, it was decided to use the direct, indirect
system of heating. In the direct system, the radiators are placed
ir the rooms and heated directly. In the indirect systen, the
air is taken from an outside source and drawn in betwwen stean
coils, by means of a blower. From the blower, the air is forced
through a tunnel to the different ovenings in the wails and then
into the rooms.

The direct system is to: furnish forty per cent of the

required heat and the indirect system sixty per cent.

AGAQYR
By using these two systems together, a good system of ventilation
to the different rooms is provided for.

The system is to be arranged so as to heat the rooms at
a temperature of seventy degrees Fahrenheit, when it is zero
degrees outdoors.

As most of the buildings on the campus are heated by steam
from the boiler house, it was decided to get the steam in the
same manner.

= DIRECT RADIATING SURFACE =

The amount of heat required for each room, depends upon
its size, the amount of air supplied and the glass and exposed
wall. surfaces, f§ince there are some losses caused by leakage
around the sash and window frames, it was necessary to allow
about ten per cent in figuring the amount of radiating surface re-
quired. The amount of radiating surface put in depended also on
the exposure of the rooms, Where the exposure Was from the
north, ten to fifteen per cent was allowed. On a west exposure
ten per cent was allowed. This rule was not strictly adhered to
because it depended largely on the size of the rooms and the size
of the radiators which did not always contain the number of
square feet requirede.

To find the amount of radiating surface required, the
following formula from Carpenter's Heating and Ventilating was
usede.

R = €0-cscegw) (f=¢_)-
55 T-t+ a

N =Number of times air is changed in rooms per hour,
C = number of cubic feet in each room.

G = number of square feet of glass surface.

W = area of exposed walls.
= temperature of room taken as seventy degrees.

= temperature outdoors " " zero °

= temperature of radiating surface.

=heat given off per square foot of radiating surface
per hour per degree difference in temperature,

@ i ct ct

This rule is not as simple as the following rules and a
comparison of same shows that Willets rule is equally as good.
= ~“MILL®S RULE FOR DIRECT RADIATION =

(Monroe's Book)

windows.
= number of cubic feet in room.

Ra .5G + .OSW + .O05C.

RK s number of square feet of radiating surface.

Gs " glass"

Wea * " " " " wall surface not including
C

This rule holds good when temperature of room is 70
degrees and outside temperature from 10 to 15 degrees below zero.
« WILLET'S RULE FOR DIRECT RADIATION =
(Monroe's Book)
= .9(t-t)(.6G + .1W + .0025C)FU = t
Factor depending on method of heating.
8 for low pressure systems.

,

z@

= factor depending on exposure of building,

=z 1 for south and east exposure and 1.4 for north and. west

ayy oD

When t is taken at 8 degrees below zero, t at 70 degrees,
F at .8 and J at 1, the formula redues to the following.

R = ,486 + .O8W + .002C

= MONROE'S RULE FOR DIRECT RADIATION =

= (1.3G + .25W + .008C} J (t-t) © (Teta
= depends om exposure and taker as l...
= temperature o¢ steam im radiator.
= " room.
= " " outside air,
2

R
J
T
t
t
a coefficient of heat transmission from a radiator

which varies from 1.7 for low pressure steam to 1.9 for 40# steam

pressure.
This reduces the formula to the following.
R= ,42G + ,O8W + .O0026C.
= STEAM MAINS =
(Mills System)

To get the best results and on account of the location
of the rooms, it was thought best to have the mains run from the
tunnel west to the main entrance. From each corner of the entr=
ance the mains extend pp to the attic floor and then in an east=
erly and westerly direction. These mains cphtinue around the
building to the south side where they decrease in size,

The return mains are to be placed in the basement and run
im the same direction as the steam mains. Between the steam mains
and the returns are the risers and from the risers, extend the
branches to the different radiators. fhe return main is to be
some what larger 80 as to equalize the pressure, in case there
should be an excess of steam in the returns. The highestpoint of
the return is to: be near the main entrance, The lowest point of
the returns will lead into two steam taps which are to. be fitted
with by-pass valves. From here the two pipes lead into one and
continue on to the tunnel.

The total amount of radiating surface is 11677 square feet,
but as 40% of this is to be direct, we have 40% of 11677 or 4671
sqe ft. of radiating surface for direct heating. To figure. the
size of main required Carpenter's table om page 223 was usede.

Assuming a velocity of 50 feet per second for steam and
a pressure of about 3 lbs, we use the tables as follows:

Column lL gives the velocity.

3 " " factor for diameter of pipe.
" 5 " " steam pressure in lbs,
Then the square root of the number of sq. feet. of
radiation x .092 gives the diameter of the steam main.,.
4671 x .0O92 = 6.25 inches diameter,

The area of a pipe 6.25 in. in diameter « 380.6 square ine
" " two pipes 4 " = 25.0 "*"

It was decided to. use the two: four inch mains and put on
a little more steam pressure if necessary. The returns were
figured wome what larger to:allow for any excess of steam that
may. pass through the risers and into the returns. This would give
the surplus steam a chance to flow up some o¢her riser and thus
equalize the pressure.

= SIZE OF RETURN MAINS #

Prof. Carpenter says that the size of a return pipe should
be about one size less than one half the size of the steam main,
Since the diameter of the steam main is 6.25 inches, the diameter
of the return main would be about 3 inches.

«= SIZE OF BRANCHES LEADING TO RADIATORS, ®
» wthe pipes running between the risers and radiators are
called branches. As there is no fixed rule for determining the

sizes of them, we have figured the sizes on the following basis.

For 20 fty.or less of radiating surface Ltt. each radiator use 1" pipe
" 20 to 60 ft. " " "12" *
v 60° Lo 8D : 7 | ve 7 7 ve 1 " ve
J 80: to OOM a] Ls] t? Ls] A] " t Qn i]

The above sizes wiil evidently give good results, since
they are generally used in the ordinary practice of steam heating.
Carpenter's, Mills and Monroe's Books om: Heating and

Ventilating were used as reference hooks for this thesis.
= SIZE OF RISERS =
To determine the size of a riser, it is necessary to: know
the amount of radiating surface to:be heated by the riser... This
amount should not exceed 400 sq. feet. In our case, we intend to
use a 2" riser throughout the building, although in some places
the 2 in. riser is a little larger than necessary and in other
places, it is a little smaller. By using the 2 in. risers, it
simplifies the piping and equalizes the steam pressure in the
risers.
= RADIATORS =
Yaving determined the amount of radiating surface reguired
in each room, the number of radiators required was figured as
follows: Each room is to have a certain number of radiators,
depending on the number of sq. feet of radiating surface. Divide
this amount into certain parts, each part corresponding to the
size of the radiator wanted.. The size of radiator depends on
its location, for if the radiator is to be near the north or
west wall, it should be larger than if placed near an inner wall.
Where the radiator has a west or north exposure, we have allowed
from 10 to 15% more, to allow for losses due to such exposures,
(See .data sheet for number of radiators and amount of radiating
surface). Also see specifications.
=.THE INDIRECT SYSTEM =

| The indirect system is to be installed with the direct
System for the purpose of furnishing 60% of the heat when it is
required and also to give good ventilation. Tou get the best ree
Bults, it was thought best to place a thermostatic valve on each
radiator, so that in case it got to warm, the thermo-stat would

close the valve.
It is intended to operate this system without opening any
of the windows,

Of course there is a limit to the amount of hot air entering
the room. fhat is, on cold days, it will probably be necessary
to. use all the four section of steam coils, which are to heat the
air, but on warmer days, it will not. There are to be four
sections, conmected so - that any one section or alli of the sections
can be shut off. The hot and cold air registers will also furnish
a method of shutting off excess of heat, although this method is
to be avoided if possible.

=z AMOUNT OF INDIRECT YEATING SURFACE REQUIRED =
First Method.
See Carpenter's book on Heating and Ventilating, page 292.

No. of square feet of radiation = -ne(t-t) = R

56a(T-t.)
T = temperature of heated surface 220°
t= " " air in the room 70°
t's " " outside air 0°
t"= tomperature of air leaving heated surface 120°

t.2 mean"temperature of air surrond heating surface 60°
tag (tt!

n * number of times air is changed in room per hour

C = number of cubic feet in rooms.

a= coefficient giving number of heat units per degree
aifference of tempprature per square foot per hour from
heating surface,

ne # 3 x 800000 = 2400000 cubic feet,
Oo
T= 220 t= 70° t.= 60° t.##(120°-0)=60 t' #0
3 x 800000(70°) |
Ro maS eee os. - = 2850 square feet radiatin.
58 (10) 180 a ° né

surface,
The number of hea .t units given off per degree difference
of temperature per square foot of surface per hour is equal to
twice the square root of the velocity of the air in feet per
second. Assuming a velocity of 25 feet per secon, we have
2V25 #:10. A= 10.

« SECOND METHOD =
Carpenter's, Page 293.

Amount of air delivered per hour # 40000 x 60 =

2400000 cu. ft.

Temperature of air to be delivered into room = 130°

Steam pressure in coils = 3

Temperature of condensed water = 213°

At 3# pressure Qbove atmosphere = 17.7 = 1181 BTU.

1181 BTU in 1# steam

213 \" =" 1# water

968 " given off by heating surface.

See Garpenter's table 8, page 382.At 70° one heat
unit willi warm 56 cu. ft. ofair one degree and to heat one cubic
foot 130° will require 2.32 heat units. Each pound of steam
gives off 968 heat units and will. heat 450 cu. fset of air from

O

zero to 130°. To heat 2400000 cu. feet of air to 130° will

require 5334# of stean.

The indirect heater with blower attachment will: condense
about 2# of water per square foot ofsurface per hour, 4aence the
total amount of square feet of surface is equal to.5334 lbs.
divided by, 2 = 2660 square feet of radiating surface,.

= AIR SUPPLIED PER OUR =

The amount of air supplied per how to each room was

figured as follows,
Allowing 40000 cubic feet per minute as the canacity of the
blower, the total number of square feet in the warm air
registers was found. Then dividing the number of cubic feet by
the area gives the number of cubic feet per ome square foot of
register area, Multiplying this by the area of each register
gives the amount of air flowing through register per one minute.

2 0000 eee eee x size ofregister in sq. feet x 60

Area of registers in sq. feet
=z amt of air per hours.
= SIZE OF HOT AIR REGISTER =

See Carpenter's, page 53.

Velocity of air taken at 3 ft. per secondand air is to
be changed 3 times per hour. mrhen from the tables we have 40
square inches in area per 1000 cu. ft. of air. Divide the total
volume of each room by 1000 and multiply by 40, and the result
will: be the area of the register. The net area of the register
should be from .5 to..7 of the nominal area,

To get the best results with the circulation of air in
the rooms, it is necessary to have the hot air register about 7
feet above the floor and the cold air register on the same side
of room and near the floor. (See data sheet for size of
registers)

= THE MAIN DUCT AND BRANCHES =

To get the best results and to save as much space as
possible, it was decided to have the hot air duct run under the
Ground floor in an easterly and westerly, direction. At the east
end the duct branches north and south, being some what smaller in

size than the main duct.
The blower is to be located in the fan room, which is the
first room east of the main entrance. The duct is to come to a
piace directly under the blower, and from here, the duct runs dus
west and then makes a large turn to the south and into the main
duct.

= SIZE OF TUNNEL =

Toodeterminethe size of duct required.(See Carpenter's
page 53). The nundver of cubic feet of air per hour is 2400000.
Assuming the velocity to be 15 feet per second, we find in the
tables the factor 26.6, which ia to be multiplied by(2400000 os
10000) which is equal to 6384, This amount 6384 — 144 gives
45 square feet, which would be equal tothe cross sectional area
of the tunnel. This would enable us to use a tunnel about 64 x
7 feet in size,

| « SIZE OF BLOWER =»

There is one thing that must not be overlooked, figuring
out the sige of the blower and that is that it should run without
making too. nuch noise. To be able to do this and get the best
results, the blower should run from 180 to 200 revolutions per
minute.

To figure out the size of the blower,, we know that it must
be able to deliver about 40000 cubic feet of air per one ninute.
Since the blower is to stand im am open room and have a free out-
let, it will) be able to discharge air at a velocity nearly 10%
greater than the peripheral velocity of the fan blades. When the
blower is arranged so it will draw its supply ofair through banks
of heated colls and discharge tHrough the tumrel, the resistance
due to friction is so great that it reduces the velocity about
50%.
a ey
To allow for this loss and to:retain a factor of safety,
it 18 necessary tovhave the peripheral velocity of the fan blades
equal to the linear velocity of the air and the efficiency of
delivery is to: be 50% of the latter amount. Assuming the
diameter of the fan as 8 feet, we will seeif it willl fufull our
conditions, :

8 ft. x 3.1416 x 180 = 4536 ft. using 180 RPM

But since we must ailow 50% for friction, we have 4536+
2 = 2268 ft. per minute.

The size of opening for an eight foot fan is about 19
square feet. Multinlying 2268 feet per minute by 19 sq. ft. gives
43092 cubic feet. This willibe the amount of air delivered per
minute, which is somewhat larger than we used.

= POWER REQUIRED =

According to Carpenter's tables of capacity and power of
blowers, a 7 3. YP. engine would run the blower. But the blower
igs to be run by: an electric motor instead of an engine. To be on
the safe side in case a greater speed is desired, al2to 16 i,?r.
motor was thought sufficiently large enough to run the blower.

Specification for a Yeating and Ventilating system to: be
installed in the New Engineering Building at the Michigan
Agricultural College.

= CONSTRUCTION =

The heating system proposed i8 to be a direct, indirect
System and to include the furnishing, delivery and complete
erection, in said building and at the above place, all material
and labor which shall. enter into othe construction of the above

system.
All work lis to be first class and done in a workmanlike marner

and according to the following specifications,

The words "Owner" and "Contractor" refer respectively. to
owning the building and the party doing the work.

The system is to be erected in twc parts,(See drawings of
elevations) the east and west half. It is to be a low pressure,
gravity system and sovarranged that the radiators car be shut off
without interfering with the ctrculation system.

All main risers leading from the basement to the top floor
are to be properly supported and fastened by wrought iron straps.
All mains running in the direction, as the flow of the steam are
to have a fall of one inch in every twelve feet.

= PIPES AND FITTINGS =

All necessary pipes and fittings are to be of such sizes
and connected as shown on drawings, so as to give a free and
noiseless circulation. The system is to be free from all water
pocketse

Wrought irom shall be of standard quality and as follows:

All pipes 14" in diameter and above are to be lap welded
and tested to 300 per square inch.

All piping and fittings are to be exposed. All: mains
and returns passing through walls are to have wrought iron thimbles
with cast iron flanges on each side of the wall.

A two pipe coil is to be placed along the east wall of the
dark and wash rooms located on the top floor. This coil is to
be about 30 ft. long and made up of 14" pipe. It is to have

a Fairbanks Radiator valve and Allen's automatic air valve,
All mains to be 3" = 33" and 4" as shown on elevation dravings.
" returns " * 3" n ' of tt tt
Ui risers | fe Off oN" ” La] ? ve wv
= HEATING COILS =

The heating coils which are to be used far the indirect
system are to: be erected in the basement and placed in their proper
Place... The pipes are to:be 1" in diameter and 2%" from center to
center. These coils are to be made into 20 sections, each section
being made up of a cast iron header with holes tapped for pipes
and.an.opening for the feed pipe om the front end and an air pipe
on the rear end.(See drawings for same.) All air pipes to.extend
above the sheet iron covering and connected with automatic vacum
valves.

Each section is tobe tested long enough to see if coils
are free from leaks. Each section is to be connected to the feed
pipe which is conrected to the main header above. This header
connects tovthe main leading touthe tunnel.

« HBUSING THE COILS =

The contractor is to:;house in the coils with No. 18 gauge
sheet steel, all properly riveted and supported. The east end of
housing to be left open for the supply of cold air. The front
portion of the housing is to be so arranged that the sheets can
be taken off and any desired sectiom removed without disturbing

the other. part of the housing. The housing to be made tight aroumil
the blower. The housimg:.is to-be painted with one coat of

asphaltum varnish on the inside and two coats on the outside. For
the sizes of angle and tee irons to:-be used in the construction

of the housing. (See drawings and details of same.)
= RADIATORS =

The radiators are to be of Berfectiom pattern and of
such size as specified..
All radiators carrying 20 ft. or less of radiation tohave 1"
radiator valves.
All radiators carrying 20 to 60 ft of radi&tion to have 13"
radiator valves.
All radiators carrying 60 to 80 ft. of radiation to have 1#"
radiator valves.
All radiators carrying 80 to 100 ft. of radiation to have 2"
radiator valvese
All radiators to be fitted with Allen automatic air valve.
= FLOOR AND CEILING PLATES =
All pipes passing through walls, partitions and floors
must be provided with galvanized iron sleeves and all necessary
floor and ceiling plates. The Crane cast iron floor and ceiling
plates to be used.
=z VALVES =

The Fairbanks Radiator Valve with thermostatic conrections
is to be used throughout the building on all direct radiation.
All radiator valves to have ground joints and union eouplings.

= PIPE COVERING =

All mains to be covered with pipe covering composed of
85 % magnesia and 15% asbestos and to be 1" :hhick.e After the
mains are covered, they are to be painted with one coat of fire
proof mineral paint.

* CARPENTER AND MASON WORK =

All necessary mason and carpenter work to be done by
_the masorr and carpenter contractors on the building.. The steam
fitter must give the contractor sufficient time to docany. cutting
or changing that he orders,. providing that the changes ordered
are approved by the superintendent of the tuilding.

= DECORATING =
All painting and decorating(not includingthe mains) is to

be done by the owner,
= TEMPORARY HEAT =

Temporary heat is to be furnished when the owner thinks
it is necessary and he is to take the responsibility for any
damage to the work that may be caused from same,

=. CHANGES IN THE WORK =

Any changes made im the plans or specifications are to be
submitted to: the owner or his superintendent who is to. have charge
of the work. Upon his consent for any change, a written request
for this change must be handed to the superintendent and he is to
keep a record of same. If any of these changes are extra, or the
change im the work is a saving for the owner,. then they are to be
allowed for at the same rate as the contract price...

«= COMPLETION OF THE CONTRACT.=

When the heating system is completed and ready for testing,
the contractor is to notify the owner, who is to. make the final
inspectiom of the work. If for any reason that the ownexp should
overlook some detail of the work and said work not being acdording
to plans or specifications, the contractor is to:-be held responsibl¢
for same.

The contractor is not ta be held responsible for any
delay in his work it is caused by other contractors or by, changes
im the work which are suggested and ordered done by, the owner.

@ PAYMENTS =

No work is to be paid for unless same is inspected by the
owner or his superintendent. ‘The payments are to be made as the
work proceeds and om a basis of 70% of the value of the work at
the time of payment..

= FINAL =
These specifications cover everything necessary to make a

first class direct, indirect steam heating system. If at any
  

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time that the contractor does not clearly understand the full

meaning of the plans or specifications, he is expected to see the
superintendent and get his interpretation of same. The plans of
the heating system and of the building are to be used to: the best
of advantage. All_final measurements are tobe taken from the
building and not from the drawings.

= BILL OF MATERIAL.=

561 ft. of 4" wrought irom pipe

75 "34" "

565 v? La ia 7 ?
1868 we ” on e a] re

360 v "ian vf " L

305 " "12" " Ss ] te

50 " " 1" a] ef Cs]

21" Fairbanks Thermostatic Radiator Valves.
45 1:

65 13" ve | # o

6 e | , en . § w

118 Allen's automatic air valves.
‘ 92 4" Gate valves.
aT ate Cast irom pipe flanges for brick wall.

7 3" te w | | ve |
6 4" Pie sufports in basement.
54 3" "

= RADIATORS =

No. Radiating Surface(Sq. Ft.) Sections Height Length.
30 78 19 38" 474"
2 92 23 38" 57a"
4 52 13 38" 32a"
3 56 L4 38" 25"
9 48. 12 38" 30*
5 36 9: 38" 224"
2 24 9 26" 225"
3 157 28: 38" 70"
6 72 “ 1& 38" 45"
1 80: 15 ge" 3t4"
L 16 4 26" 10*
1 20 5 26" 123"
1 40 10 38"  25*
8 60 15 38" 37%"
Ll 64 16 38" 40"
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Sections

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Height

38"
38"
38"
38"

Length.

422"
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MICHIGAN STATE UNIV. LIBRARIES

iii

1293017488754